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Refactor ShardedCache for more sharing, static polymorphism (#10801) 

Summary:
The motivations for this change include
* Free up space in ClockHandle so that we can add data for secondary cache handling while still keeping within single cache line (64 byte) size.
  * This change frees up space by eliminating the need for the `hash` field by making the fixed-size key itself a hash, using a 128-bit bijective (lossless) hash.
* Generally more customizability of ShardedCache (such as hashing) without worrying about virtual call overheads
  * ShardedCache now uses static polymorphism (template) instead of dynamic polymorphism (virtual overrides) for the CacheShard. No obvious performance benefit is seen from the change (as mostly expected; most calls to virtual functions in CacheShard could already be optimized to static calls), but offers more flexibility without incurring the runtime cost of adhering to a common interface (without type parameters or static callbacks).
  * You'll also notice less `reinterpret_cast`ing and other boilerplate in the Cache implementations, as this can go in ShardedCache.

More detail:
* Don't have LRUCacheShard maintain `std::shared_ptr<SecondaryCache>` copies (extra refcount) when LRUCache can be in charge of keeping a `shared_ptr`.
* Renamed `capacity_mutex_` to `config_mutex_` to better represent the scope of what it guards.
* Some preparation for 64-bit hash and indexing in LRUCache, but didn't include the full change because of slight performance regression.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10801

Test Plan:
Unit test updates were non-trivial because of major changes to the ClockCacheShard interface in handling of key vs. hash.

Performance:
Create with `TEST_TMPDIR=/dev/shm ./db_bench -benchmarks=fillrandom -num=30000000 -disable_wal=1 -bloom_bits=16`

Test with
```
TEST_TMPDIR=/dev/shm ./db_bench -benchmarks=readrandom[-X1000] -readonly -num=30000000 -bloom_bits=16 -cache_index_and_filter_blocks=1 -cache_size=610000000 -duration 20 -threads=16
```

Before: `readrandom [AVG 150 runs] : 321147 (± 253) ops/sec`
After: `readrandom [AVG 150 runs] : 321530 (± 326) ops/sec`

So possibly ~0.1% improvement.

And with `-cache_type=hyper_clock_cache`:
Before: `readrandom [AVG 30 runs] : 614126 (± 7978) ops/sec`
After: `readrandom [AVG 30 runs] : 645349 (± 8087) ops/sec`

So roughly 5% improvement!

Reviewed By: anand1976

Differential Revision: D40252236

Pulled By: pdillinger

fbshipit-source-id: ff8fc70ef569585edc95bcbaaa0386f61355ae5b
This commit is contained in:
Peter Dillinger 2022-10-18 22:06:57 -07:00 committed by Facebook GitHub Bot
parent e267909ecf
commit 7555243bcf
14 changed files with 809 additions and 882 deletions
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8
cache/cache_test.cc vendored
View File

@ -1023,21 +1023,21 @@ TEST_P(CacheTest, DefaultShardBits) {
(GetParam() == kHyperClock ? 32U * 1024U : 512U) * 1024U;
std::shared_ptr<Cache> cache = NewCache(32U * min_shard_size);
ShardedCache* sc = dynamic_cast<ShardedCache*>(cache.get());
ShardedCacheBase* sc = dynamic_cast<ShardedCacheBase*>(cache.get());
ASSERT_EQ(5, sc->GetNumShardBits());
cache = NewCache(min_shard_size / 1000U * 999U);
sc = dynamic_cast<ShardedCache*>(cache.get());
sc = dynamic_cast<ShardedCacheBase*>(cache.get());
ASSERT_EQ(0, sc->GetNumShardBits());
cache = NewCache(3U * 1024U * 1024U * 1024U);
sc = dynamic_cast<ShardedCache*>(cache.get());
sc = dynamic_cast<ShardedCacheBase*>(cache.get());
// current maximum of 6
ASSERT_EQ(6, sc->GetNumShardBits());
if constexpr (sizeof(size_t) > 4) {
cache = NewCache(128U * min_shard_size);
sc = dynamic_cast<ShardedCache*>(cache.get());
sc = dynamic_cast<ShardedCacheBase*>(cache.get());
// current maximum of 6
ASSERT_EQ(6, sc->GetNumShardBits());
}

231
cache/clock_cache.cc vendored
View File

@ -12,6 +12,7 @@
#include <cassert>
#include <functional>
#include "cache/cache_key.h"
#include "monitoring/perf_context_imp.h"
#include "monitoring/statistics.h"
#include "port/lang.h"
@ -29,16 +30,22 @@ inline uint64_t GetRefcount(uint64_t meta) {
ClockHandle::kCounterMask;
}
void ClockHandleBasicData::FreeData() const {
if (deleter) {
UniqueId64x2 unhashed;
(*deleter)(ClockCacheShard::ReverseHash(hashed_key, &unhashed), value);
}
}
static_assert(sizeof(ClockHandle) == 64U,
"Expecting size / alignment with common cache line size");
ClockHandleTable::ClockHandleTable(int hash_bits, bool initial_charge_metadata)
: length_bits_(hash_bits),
length_bits_mask_(Lower32of64((uint64_t{1} << length_bits_) - 1)),
occupancy_limit_(static_cast<uint32_t>((uint64_t{1} << length_bits_) *
length_bits_mask_((size_t{1} << length_bits_) - 1),
occupancy_limit_(static_cast<size_t>((uint64_t{1} << length_bits_) *
kStrictLoadFactor)),
array_(new ClockHandle[size_t{1} << length_bits_]) {
assert(hash_bits <= 32); // FIXME: ensure no overlap with sharding bits
if (initial_charge_metadata) {
usage_ += size_t{GetTableSize()} * sizeof(ClockHandle);
}
@ -47,7 +54,7 @@ ClockHandleTable::ClockHandleTable(int hash_bits, bool initial_charge_metadata)
ClockHandleTable::~ClockHandleTable() {
// Assumes there are no references or active operations on any slot/element
// in the table.
for (uint32_t i = 0; i < GetTableSize(); i++) {
for (size_t i = 0; i < GetTableSize(); i++) {
ClockHandle& h = array_[i];
switch (h.meta >> ClockHandle::kStateShift) {
case ClockHandle::kStateEmpty:
@ -58,7 +65,7 @@ ClockHandleTable::~ClockHandleTable() {
assert(GetRefcount(h.meta) == 0);
h.FreeData();
#ifndef NDEBUG
Rollback(h.hash, &h);
Rollback(h.hashed_key, &h);
usage_.fetch_sub(h.total_charge, std::memory_order_relaxed);
occupancy_.fetch_sub(1U, std::memory_order_relaxed);
#endif
@ -71,7 +78,7 @@ ClockHandleTable::~ClockHandleTable() {
}
#ifndef NDEBUG
for (uint32_t i = 0; i < GetTableSize(); i++) {
for (size_t i = 0; i < GetTableSize(); i++) {
assert(array_[i].displacements.load() == 0);
}
#endif
@ -154,12 +161,12 @@ inline void CorrectNearOverflow(uint64_t old_meta,
}
}
Status ClockHandleTable::Insert(const ClockHandleMoreData& proto,
Status ClockHandleTable::Insert(const ClockHandleBasicData& proto,
ClockHandle** handle, Cache::Priority priority,
size_t capacity, bool strict_capacity_limit) {
// Do we have the available occupancy? Optimistically assume we do
// and deal with it if we don't.
uint32_t old_occupancy = occupancy_.fetch_add(1, std::memory_order_acquire);
size_t old_occupancy = occupancy_.fetch_add(1, std::memory_order_acquire);
auto revert_occupancy_fn = [&]() {
occupancy_.fetch_sub(1, std::memory_order_relaxed);
};
@ -198,7 +205,7 @@ Status ClockHandleTable::Insert(const ClockHandleMoreData& proto,
}
if (request_evict_charge > 0) {
size_t evicted_charge = 0;
uint32_t evicted_count = 0;
size_t evicted_count = 0;
Evict(request_evict_charge, &evicted_charge, &evicted_count);
occupancy_.fetch_sub(evicted_count, std::memory_order_release);
if (LIKELY(evicted_charge > need_evict_charge)) {
@ -263,7 +270,7 @@ Status ClockHandleTable::Insert(const ClockHandleMoreData& proto,
need_evict_charge = 1;
}
size_t evicted_charge = 0;
uint32_t evicted_count = 0;
size_t evicted_count = 0;
if (need_evict_charge > 0) {
Evict(need_evict_charge, &evicted_charge, &evicted_count);
// Deal with potential occupancy deficit
@ -323,9 +330,9 @@ Status ClockHandleTable::Insert(const ClockHandleMoreData& proto,
}
assert(initial_countdown > 0);
uint32_t probe = 0;
size_t probe = 0;
ClockHandle* e = FindSlot(
proto.hash,
proto.hashed_key,
[&](ClockHandle* h) {
// Optimistically transition the slot from "empty" to
// "under construction" (no effect on other states)
@ -338,7 +345,7 @@ Status ClockHandleTable::Insert(const ClockHandleMoreData& proto,
if (old_state == ClockHandle::kStateEmpty) {
// We've started inserting into an available slot, and taken
// ownership Save data fields
ClockHandleMoreData* h_alias = h;
ClockHandleBasicData* h_alias = h;
*h_alias = proto;
// Transition from "under construction" state to "visible" state
@ -375,7 +382,7 @@ Status ClockHandleTable::Insert(const ClockHandleMoreData& proto,
if ((old_meta >> ClockHandle::kStateShift) ==
ClockHandle::kStateVisible) {
// Acquired a read reference
if (h->key == proto.key) {
if (h->hashed_key == proto.hashed_key) {
// Match. Release in a way that boosts the clock state
old_meta = h->meta.fetch_add(
ClockHandle::kReleaseIncrement * initial_countdown,
@ -431,7 +438,7 @@ Status ClockHandleTable::Insert(const ClockHandleMoreData& proto,
return Status::OK();
}
// Roll back table insertion
Rollback(proto.hash, e);
Rollback(proto.hashed_key, e);
revert_occupancy_fn();
// Maybe fall back on detached insert
if (handle == nullptr) {
@ -446,7 +453,7 @@ Status ClockHandleTable::Insert(const ClockHandleMoreData& proto,
assert(use_detached_insert);
ClockHandle* h = new ClockHandle();
ClockHandleMoreData* h_alias = h;
ClockHandleBasicData* h_alias = h;
*h_alias = proto;
h->detached = true;
// Single reference (detached entries only created if returning a refed
@ -467,10 +474,10 @@ Status ClockHandleTable::Insert(const ClockHandleMoreData& proto,
return Status::OkOverwritten();
}
ClockHandle* ClockHandleTable::Lookup(const CacheKeyBytes& key, uint32_t hash) {
uint32_t probe = 0;
ClockHandle* ClockHandleTable::Lookup(const UniqueId64x2& hashed_key) {
size_t probe = 0;
ClockHandle* e = FindSlot(
hash,
hashed_key,
[&](ClockHandle* h) {
// Mostly branch-free version (similar performance)
/*
@ -501,7 +508,7 @@ ClockHandle* ClockHandleTable::Lookup(const CacheKeyBytes& key, uint32_t hash) {
if ((old_meta >> ClockHandle::kStateShift) ==
ClockHandle::kStateVisible) {
// Acquired a read reference
if (h->key == key) {
if (h->hashed_key == hashed_key) {
// Match
return true;
} else {
@ -596,7 +603,7 @@ bool ClockHandleTable::Release(ClockHandle* h, bool useful,
delete h;
detached_usage_.fetch_sub(total_charge, std::memory_order_relaxed);
} else {
uint32_t hash = h->hash;
UniqueId64x2 hashed_key = h->hashed_key;
#ifndef NDEBUG
// Mark slot as empty, with assertion
old_meta = h->meta.exchange(0, std::memory_order_release);
@ -607,7 +614,7 @@ bool ClockHandleTable::Release(ClockHandle* h, bool useful,
h->meta.store(0, std::memory_order_release);
#endif
occupancy_.fetch_sub(1U, std::memory_order_release);
Rollback(hash, h);
Rollback(hashed_key, h);
}
usage_.fetch_sub(total_charge, std::memory_order_relaxed);
assert(usage_.load(std::memory_order_relaxed) < SIZE_MAX / 2);
@ -654,10 +661,10 @@ void ClockHandleTable::TEST_ReleaseN(ClockHandle* h, size_t n) {
}
}
void ClockHandleTable::Erase(const CacheKeyBytes& key, uint32_t hash) {
uint32_t probe = 0;
void ClockHandleTable::Erase(const UniqueId64x2& hashed_key) {
size_t probe = 0;
(void)FindSlot(
hash,
hashed_key,
[&](ClockHandle* h) {
// Could be multiple entries in rare cases. Erase them all.
// Optimistically increment acquire counter
@ -667,7 +674,7 @@ void ClockHandleTable::Erase(const CacheKeyBytes& key, uint32_t hash) {
if ((old_meta >> ClockHandle::kStateShift) ==
ClockHandle::kStateVisible) {
// Acquired a read reference
if (h->key == key) {
if (h->hashed_key == hashed_key) {
// Match. Set invisible.
old_meta =
h->meta.fetch_and(~(uint64_t{ClockHandle::kStateVisibleBit}
@ -691,7 +698,7 @@ void ClockHandleTable::Erase(const CacheKeyBytes& key, uint32_t hash) {
<< ClockHandle::kStateShift,
std::memory_order_acq_rel)) {
// Took ownership
assert(hash == h->hash);
assert(hashed_key == h->hashed_key);
// TODO? Delay freeing?
h->FreeData();
usage_.fetch_sub(h->total_charge, std::memory_order_relaxed);
@ -706,7 +713,7 @@ void ClockHandleTable::Erase(const CacheKeyBytes& key, uint32_t hash) {
h->meta.store(0, std::memory_order_release);
#endif
occupancy_.fetch_sub(1U, std::memory_order_release);
Rollback(hash, h);
Rollback(hashed_key, h);
break;
}
}
@ -735,14 +742,14 @@ void ClockHandleTable::Erase(const CacheKeyBytes& key, uint32_t hash) {
}
void ClockHandleTable::ConstApplyToEntriesRange(
std::function<void(const ClockHandle&)> func, uint32_t index_begin,
uint32_t index_end, bool apply_if_will_be_deleted) const {
std::function<void(const ClockHandle&)> func, size_t index_begin,
size_t index_end, bool apply_if_will_be_deleted) const {
uint64_t check_state_mask = ClockHandle::kStateShareableBit;
if (!apply_if_will_be_deleted) {
check_state_mask |= ClockHandle::kStateVisibleBit;
}
for (uint32_t i = index_begin; i < index_end; i++) {
for (size_t i = index_begin; i < index_end; i++) {
ClockHandle& h = array_[i];
// Note: to avoid using compare_exchange, we have to be extra careful.
@ -776,7 +783,7 @@ void ClockHandleTable::ConstApplyToEntriesRange(
}
void ClockHandleTable::EraseUnRefEntries() {
for (uint32_t i = 0; i <= this->length_bits_mask_; i++) {
for (size_t i = 0; i <= this->length_bits_mask_; i++) {
ClockHandle& h = array_[i];
uint64_t old_meta = h.meta.load(std::memory_order_relaxed);
@ -788,7 +795,7 @@ void ClockHandleTable::EraseUnRefEntries() {
<< ClockHandle::kStateShift,
std::memory_order_acquire)) {
// Took ownership
uint32_t hash = h.hash;
UniqueId64x2 hashed_key = h.hashed_key;
h.FreeData();
usage_.fetch_sub(h.total_charge, std::memory_order_relaxed);
#ifndef NDEBUG
@ -801,37 +808,29 @@ void ClockHandleTable::EraseUnRefEntries() {
h.meta.store(0, std::memory_order_release);
#endif
occupancy_.fetch_sub(1U, std::memory_order_release);
Rollback(hash, &h);
Rollback(hashed_key, &h);
}
}
}
namespace {
inline uint32_t Remix1(uint32_t hash) {
return Lower32of64((uint64_t{hash} * 0xbc9f1d35) >> 29);
}
inline uint32_t Remix2(uint32_t hash) {
return Lower32of64((uint64_t{hash} * 0x7a2bb9d5) >> 29);
}
} // namespace
ClockHandle* ClockHandleTable::FindSlot(
uint32_t hash, std::function<bool(ClockHandle*)> match_fn,
const UniqueId64x2& hashed_key, std::function<bool(ClockHandle*)> match_fn,
std::function<bool(ClockHandle*)> abort_fn,
std::function<void(ClockHandle*)> update_fn, uint32_t& probe) {
std::function<void(ClockHandle*)> update_fn, size_t& probe) {
// NOTE: upper 32 bits of hashed_key[0] is used for sharding
//
// We use double-hashing probing. Every probe in the sequence is a
// pseudorandom integer, computed as a linear function of two random hashes,
// which we call base and increment. Specifically, the i-th probe is base + i
// * increment modulo the table size.
uint32_t base = ModTableSize(Remix1(hash));
size_t base = static_cast<size_t>(hashed_key[1]);
// We use an odd increment, which is relatively prime with the power-of-two
// table size. This implies that we cycle back to the first probe only
// after probing every slot exactly once.
// TODO: we could also reconsider linear probing, though locality benefits
// are limited because each slot is a full cache line
uint32_t increment = Remix2(hash) | 1U;
uint32_t current = ModTableSize(base + probe * increment);
size_t increment = static_cast<size_t>(hashed_key[0]) | 1U;
size_t current = ModTableSize(base + probe * increment);
while (probe <= length_bits_mask_) {
ClockHandle* h = &array_[current];
if (match_fn(h)) {
@ -849,22 +848,23 @@ ClockHandle* ClockHandleTable::FindSlot(
return nullptr;
}
void ClockHandleTable::Rollback(uint32_t hash, const ClockHandle* h) {
uint32_t current = ModTableSize(Remix1(hash));
uint32_t increment = Remix2(hash) | 1U;
for (uint32_t i = 0; &array_[current] != h; i++) {
void ClockHandleTable::Rollback(const UniqueId64x2& hashed_key,
const ClockHandle* h) {
size_t current = ModTableSize(hashed_key[1]);
size_t increment = static_cast<size_t>(hashed_key[0]) | 1U;
for (size_t i = 0; &array_[current] != h; i++) {
array_[current].displacements.fetch_sub(1, std::memory_order_relaxed);
current = ModTableSize(current + increment);
}
}
void ClockHandleTable::Evict(size_t requested_charge, size_t* freed_charge,
uint32_t* freed_count) {
size_t* freed_count) {
// precondition
assert(requested_charge > 0);
// TODO: make a tuning parameter?
constexpr uint32_t step_size = 4;
constexpr size_t step_size = 4;
// First (concurrent) increment clock pointer
uint64_t old_clock_pointer =
@ -879,7 +879,7 @@ void ClockHandleTable::Evict(size_t requested_charge, size_t* freed_charge,
old_clock_pointer + (ClockHandle::kMaxCountdown << length_bits_);
for (;;) {
for (uint32_t i = 0; i < step_size; i++) {
for (size_t i = 0; i < step_size; i++) {
ClockHandle& h = array_[ModTableSize(Lower32of64(old_clock_pointer + i))];
uint64_t meta = h.meta.load(std::memory_order_relaxed);
@ -920,7 +920,7 @@ void ClockHandleTable::Evict(size_t requested_charge, size_t* freed_charge,
<< ClockHandle::kStateShift,
std::memory_order_acquire)) {
// Took ownership
uint32_t hash = h.hash;
const UniqueId64x2& hashed_key = h.hashed_key;
// TODO? Delay freeing?
h.FreeData();
*freed_charge += h.total_charge;
@ -934,7 +934,7 @@ void ClockHandleTable::Evict(size_t requested_charge, size_t* freed_charge,
h.meta.store(0, std::memory_order_release);
#endif
*freed_count += 1;
Rollback(hash, &h);
Rollback(hashed_key, &h);
}
}
@ -955,7 +955,7 @@ void ClockHandleTable::Evict(size_t requested_charge, size_t* freed_charge,
ClockCacheShard::ClockCacheShard(
size_t capacity, size_t estimated_value_size, bool strict_capacity_limit,
CacheMetadataChargePolicy metadata_charge_policy)
: CacheShard(metadata_charge_policy),
: CacheShardBase(metadata_charge_policy),
table_(
CalcHashBits(capacity, estimated_value_size, metadata_charge_policy),
/*initial_charge_metadata*/ metadata_charge_policy ==
@ -971,31 +971,33 @@ void ClockCacheShard::EraseUnRefEntries() { table_.EraseUnRefEntries(); }
void ClockCacheShard::ApplyToSomeEntries(
const std::function<void(const Slice& key, void* value, size_t charge,
DeleterFn deleter)>& callback,
uint32_t average_entries_per_lock, uint32_t* state) {
size_t average_entries_per_lock, size_t* state) {
// The state is essentially going to be the starting hash, which works
// nicely even if we resize between calls because we use upper-most
// hash bits for table indexes.
uint32_t length_bits = table_.GetLengthBits();
uint32_t length = table_.GetTableSize();
size_t length_bits = table_.GetLengthBits();
size_t length = table_.GetTableSize();
assert(average_entries_per_lock > 0);
// Assuming we are called with same average_entries_per_lock repeatedly,
// this simplifies some logic (index_end will not overflow).
assert(average_entries_per_lock < length || *state == 0);
uint32_t index_begin = *state >> (32 - length_bits);
uint32_t index_end = index_begin + average_entries_per_lock;
size_t index_begin = *state >> (sizeof(size_t) * 8u - length_bits);
size_t index_end = index_begin + average_entries_per_lock;
if (index_end >= length) {
// Going to end.
index_end = length;
*state = UINT32_MAX;
*state = SIZE_MAX;
} else {
*state = index_end << (32 - length_bits);
*state = index_end << (sizeof(size_t) * 8u - length_bits);
}
table_.ConstApplyToEntriesRange(
[callback](const ClockHandle& h) {
callback(h.KeySlice(), h.value, h.total_charge, h.deleter);
UniqueId64x2 unhashed;
callback(ReverseHash(h.hashed_key, &unhashed), h.value, h.total_charge,
h.deleter);
},
index_begin, index_end, false);
}
@ -1011,7 +1013,7 @@ int ClockCacheShard::CalcHashBits(
uint64_t num_slots =
static_cast<uint64_t>(capacity / average_slot_charge + 0.999999);
int hash_bits = std::min(FloorLog2((num_slots << 1) - 1), 32);
int hash_bits = FloorLog2((num_slots << 1) - 1);
if (metadata_charge_policy == kFullChargeCacheMetadata) {
// For very small estimated value sizes, it's possible to overshoot
while (hash_bits > 0 &&
@ -1033,17 +1035,16 @@ void ClockCacheShard::SetStrictCapacityLimit(bool strict_capacity_limit) {
// next Insert will take care of any necessary evictions
}
Status ClockCacheShard::Insert(const Slice& key, uint32_t hash, void* value,
size_t charge, Cache::DeleterFn deleter,
Cache::Handle** handle,
Status ClockCacheShard::Insert(const Slice& key, const UniqueId64x2& hashed_key,
void* value, size_t charge,
Cache::DeleterFn deleter, ClockHandle** handle,
Cache::Priority priority) {
if (UNLIKELY(key.size() != kCacheKeySize)) {
return Status::NotSupported("ClockCache only supports key size " +
std::to_string(kCacheKeySize) + "B");
}
ClockHandleMoreData proto;
proto.key = *reinterpret_cast<const CacheKeyBytes*>(key.data());
proto.hash = hash;
ClockHandleBasicData proto;
proto.hashed_key = hashed_key;
proto.value = value;
proto.deleter = deleter;
proto.total_charge = charge;
@ -1054,49 +1055,47 @@ Status ClockCacheShard::Insert(const Slice& key, uint32_t hash, void* value,
return s;
}
Cache::Handle* ClockCacheShard::Lookup(const Slice& key, uint32_t hash) {
ClockHandle* ClockCacheShard::Lookup(const Slice& key,
const UniqueId64x2& hashed_key) {
if (UNLIKELY(key.size() != kCacheKeySize)) {
return nullptr;
}
auto key_bytes = reinterpret_cast<const CacheKeyBytes*>(key.data());
return reinterpret_cast<Cache::Handle*>(table_.Lookup(*key_bytes, hash));
return table_.Lookup(hashed_key);
}
bool ClockCacheShard::Ref(Cache::Handle* h) {
bool ClockCacheShard::Ref(ClockHandle* h) {
if (h == nullptr) {
return false;
}
table_.Ref(*reinterpret_cast<ClockHandle*>(h));
table_.Ref(*h);
return true;
}
bool ClockCacheShard::Release(Cache::Handle* handle, bool useful,
bool ClockCacheShard::Release(ClockHandle* handle, bool useful,
bool erase_if_last_ref) {
if (handle == nullptr) {
return false;
}
return table_.Release(reinterpret_cast<ClockHandle*>(handle), useful,
erase_if_last_ref);
return table_.Release(handle, useful, erase_if_last_ref);
}
void ClockCacheShard::TEST_RefN(Cache::Handle* h, size_t n) {
table_.TEST_RefN(*reinterpret_cast<ClockHandle*>(h), n);
void ClockCacheShard::TEST_RefN(ClockHandle* h, size_t n) {
table_.TEST_RefN(*h, n);
}
void ClockCacheShard::TEST_ReleaseN(Cache::Handle* h, size_t n) {
table_.TEST_ReleaseN(reinterpret_cast<ClockHandle*>(h), n);
void ClockCacheShard::TEST_ReleaseN(ClockHandle* h, size_t n) {
table_.TEST_ReleaseN(h, n);
}
bool ClockCacheShard::Release(Cache::Handle* handle, bool erase_if_last_ref) {
bool ClockCacheShard::Release(ClockHandle* handle, bool erase_if_last_ref) {
return Release(handle, /*useful=*/true, erase_if_last_ref);
}
void ClockCacheShard::Erase(const Slice& key, uint32_t hash) {
void ClockCacheShard::Erase(const Slice& key, const UniqueId64x2& hashed_key) {
if (UNLIKELY(key.size() != kCacheKeySize)) {
return;
}
auto key_bytes = reinterpret_cast<const CacheKeyBytes*>(key.data());
table_.Erase(*key_bytes, hash);
table_.Erase(hashed_key);
}
size_t ClockCacheShard::GetUsage() const { return table_.GetUsage(); }
@ -1140,39 +1139,19 @@ size_t ClockCacheShard::GetTableAddressCount() const {
HyperClockCache::HyperClockCache(
size_t capacity, size_t estimated_value_size, int num_shard_bits,
bool strict_capacity_limit,
CacheMetadataChargePolicy metadata_charge_policy)
: ShardedCache(capacity, num_shard_bits, strict_capacity_limit),
num_shards_(1 << num_shard_bits) {
CacheMetadataChargePolicy metadata_charge_policy,
std::shared_ptr<MemoryAllocator> memory_allocator)
: ShardedCache(capacity, num_shard_bits, strict_capacity_limit,
std::move(memory_allocator)) {
assert(estimated_value_size > 0 ||
metadata_charge_policy != kDontChargeCacheMetadata);
// TODO: should not need to go through two levels of pointer indirection to
// get to table entries
shards_ = reinterpret_cast<ClockCacheShard*>(
port::cacheline_aligned_alloc(sizeof(ClockCacheShard) * num_shards_));
size_t per_shard = (capacity + (num_shards_ - 1)) / num_shards_;
for (int i = 0; i < num_shards_; i++) {
new (&shards_[i])
ClockCacheShard(per_shard, estimated_value_size, strict_capacity_limit,
metadata_charge_policy);
}
}
HyperClockCache::~HyperClockCache() {
if (shards_ != nullptr) {
assert(num_shards_ > 0);
for (int i = 0; i < num_shards_; i++) {
shards_[i].~ClockCacheShard();
}
port::cacheline_aligned_free(shards_);
}
}
CacheShard* HyperClockCache::GetShard(uint32_t shard) {
return reinterpret_cast<CacheShard*>(&shards_[shard]);
}
const CacheShard* HyperClockCache::GetShard(uint32_t shard) const {
return reinterpret_cast<CacheShard*>(&shards_[shard]);
size_t per_shard = GetPerShardCapacity();
InitShards([=](ClockCacheShard* cs) {
new (cs) ClockCacheShard(per_shard, estimated_value_size,
strict_capacity_limit, metadata_charge_policy);
});
}
void* HyperClockCache::Value(Handle* handle) {
@ -1188,18 +1167,6 @@ Cache::DeleterFn HyperClockCache::GetDeleter(Handle* handle) const {
return h->deleter;
}
uint32_t HyperClockCache::GetHash(Handle* handle) const {
return reinterpret_cast<const ClockHandle*>(handle)->hash;
}
void HyperClockCache::DisownData() {
// Leak data only if that won't generate an ASAN/valgrind warning.
if (!kMustFreeHeapAllocations) {
shards_ = nullptr;
num_shards_ = 0;
}
}
} // namespace hyper_clock_cache
// DEPRECATED (see public API)
@ -1225,7 +1192,7 @@ std::shared_ptr<Cache> HyperClockCacheOptions::MakeSharedCache() const {
}
return std::make_shared<hyper_clock_cache::HyperClockCache>(
capacity, estimated_entry_charge, my_num_shard_bits,
strict_capacity_limit, metadata_charge_policy);
strict_capacity_limit, metadata_charge_policy, memory_allocator);
}
} // namespace ROCKSDB_NAMESPACE

168
cache/clock_cache.h vendored
View File

@ -303,30 +303,24 @@ constexpr double kLoadFactor = 0.7;
// strict upper bound on the load factor.
constexpr double kStrictLoadFactor = 0.84;
using CacheKeyBytes = std::array<char, kCacheKeySize>;
struct ClockHandleBasicData {
void* value = nullptr;
Cache::DeleterFn deleter = nullptr;
CacheKeyBytes key = {};
// A lossless, reversible hash of the fixed-size (16 byte) cache key. This
// eliminates the need to store a hash separately.
UniqueId64x2 hashed_key = kNullUniqueId64x2;
size_t total_charge = 0;
Slice KeySlice() const { return Slice(key.data(), kCacheKeySize); }
// Calls deleter (if non-null) on cache key and value
void FreeData() const;
void FreeData() const {
if (deleter) {
(*deleter)(KeySlice(), value);
}
}
};
struct ClockHandleMoreData : public ClockHandleBasicData {
uint32_t hash = 0;
// Required by concept HandleImpl
const UniqueId64x2& GetHash() const { return hashed_key; }
};
// Target size to be exactly a common cache line size (see static_assert in
// clock_cache.cc)
struct ALIGN_AS(64U) ClockHandle : public ClockHandleMoreData {
struct ALIGN_AS(64U) ClockHandle : public ClockHandleBasicData {
// Constants for handling the atomic `meta` word, which tracks most of the
// state of the handle. The meta word looks like this:
// low bits high bits
@ -391,31 +385,31 @@ class ClockHandleTable {
explicit ClockHandleTable(int hash_bits, bool initial_charge_metadata);
~ClockHandleTable();
Status Insert(const ClockHandleMoreData& proto, ClockHandle** handle,
Status Insert(const ClockHandleBasicData& proto, ClockHandle** handle,
Cache::Priority priority, size_t capacity,
bool strict_capacity_limit);
ClockHandle* Lookup(const CacheKeyBytes& key, uint32_t hash);
ClockHandle* Lookup(const UniqueId64x2& hashed_key);
bool Release(ClockHandle* handle, bool useful, bool erase_if_last_ref);
void Ref(ClockHandle& handle);
void Erase(const CacheKeyBytes& key, uint32_t hash);
void Erase(const UniqueId64x2& hashed_key);
void ConstApplyToEntriesRange(std::function<void(const ClockHandle&)> func,
uint32_t index_begin, uint32_t index_end,
size_t index_begin, size_t index_end,
bool apply_if_will_be_deleted) const;
void EraseUnRefEntries();
uint32_t GetTableSize() const { return uint32_t{1} << length_bits_; }
size_t GetTableSize() const { return size_t{1} << length_bits_; }
int GetLengthBits() const { return length_bits_; }
uint32_t GetOccupancyLimit() const { return occupancy_limit_; }
size_t GetOccupancyLimit() const { return occupancy_limit_; }
uint32_t GetOccupancy() const {
size_t GetOccupancy() const {
return occupancy_.load(std::memory_order_relaxed);
}
@ -431,13 +425,15 @@ class ClockHandleTable {
private: // functions
// Returns x mod 2^{length_bits_}.
uint32_t ModTableSize(uint32_t x) { return x & length_bits_mask_; }
inline size_t ModTableSize(uint64_t x) {
return static_cast<size_t>(x) & length_bits_mask_;
}
// Runs the clock eviction algorithm trying to reclaim at least
// requested_charge. Returns how much is evicted, which could be less
// if it appears impossible to evict the requested amount without blocking.
void Evict(size_t requested_charge, size_t* freed_charge,
uint32_t* freed_count);
size_t* freed_count);
// Returns the first slot in the probe sequence, starting from the given
// probe number, with a handle e such that match(e) is true. At every
@ -450,15 +446,15 @@ class ClockHandleTable {
// value of probe is one more than the last non-aborting probe during the
// call. This is so that that the variable can be used to keep track of
// progress across consecutive calls to FindSlot.
inline ClockHandle* FindSlot(uint32_t hash,
inline ClockHandle* FindSlot(const UniqueId64x2& hashed_key,
std::function<bool(ClockHandle*)> match,
std::function<bool(ClockHandle*)> stop,
std::function<void(ClockHandle*)> update,
uint32_t& probe);
size_t& probe);
// Re-decrement all displacements in probe path starting from beginning
// until (not including) the given handle
void Rollback(uint32_t hash, const ClockHandle* h);
void Rollback(const UniqueId64x2& hashed_key, const ClockHandle* h);
private: // data
// Number of hash bits used for table index.
@ -466,10 +462,10 @@ class ClockHandleTable {
const int length_bits_;
// For faster computation of ModTableSize.
const uint32_t length_bits_mask_;
const size_t length_bits_mask_;
// Maximum number of elements the user can store in the table.
const uint32_t occupancy_limit_;
const size_t occupancy_limit_;
// Array of slots comprising the hash table.
const std::unique_ptr<ClockHandle[]> array_;
@ -484,7 +480,7 @@ class ClockHandleTable {
ALIGN_AS(CACHE_LINE_SIZE)
// Number of elements in the table.
std::atomic<uint32_t> occupancy_{};
std::atomic<size_t> occupancy_{};
// Memory usage by entries tracked by the cache (including detached)
std::atomic<size_t> usage_{};
@ -494,78 +490,107 @@ class ClockHandleTable {
}; // class ClockHandleTable
// A single shard of sharded cache.
class ALIGN_AS(CACHE_LINE_SIZE) ClockCacheShard final : public CacheShard {
class ALIGN_AS(CACHE_LINE_SIZE) ClockCacheShard final : public CacheShardBase {
public:
ClockCacheShard(size_t capacity, size_t estimated_value_size,
bool strict_capacity_limit,
CacheMetadataChargePolicy metadata_charge_policy);
~ClockCacheShard() override = default;
// TODO: document limitations
void SetCapacity(size_t capacity) override;
// For CacheShard concept
using HandleImpl = ClockHandle;
// Hash is lossless hash of 128-bit key
using HashVal = UniqueId64x2;
using HashCref = const HashVal&;
static inline uint32_t HashPieceForSharding(HashCref hash) {
return Upper32of64(hash[0]);
}
static inline HashVal ComputeHash(const Slice& key) {
assert(key.size() == kCacheKeySize);
HashVal in;
HashVal out;
// NOTE: endian dependence
// TODO: use GetUnaligned?
std::memcpy(&in, key.data(), kCacheKeySize);
BijectiveHash2x64(in[1], in[0], &out[1], &out[0]);
return out;
}
void SetStrictCapacityLimit(bool strict_capacity_limit) override;
// For reconstructing key from hashed_key. Requires the caller to provide
// backing storage for the Slice in `unhashed`
static inline Slice ReverseHash(const UniqueId64x2& hashed,
UniqueId64x2* unhashed) {
BijectiveUnhash2x64(hashed[1], hashed[0], &(*unhashed)[1], &(*unhashed)[0]);
// NOTE: endian dependence
return Slice(reinterpret_cast<const char*>(unhashed), kCacheKeySize);
}
Status Insert(const Slice& key, uint32_t hash, void* value, size_t charge,
Cache::DeleterFn deleter, Cache::Handle** handle,
Cache::Priority priority) override;
// Although capacity is dynamically changeable, the number of table slots is
// not, so growing capacity substantially could lead to hitting occupancy
// limit.
void SetCapacity(size_t capacity);
Cache::Handle* Lookup(const Slice& key, uint32_t hash) override;
void SetStrictCapacityLimit(bool strict_capacity_limit);
bool Release(Cache::Handle* handle, bool useful,
bool erase_if_last_ref) override;
Status Insert(const Slice& key, const UniqueId64x2& hashed_key, void* value,
size_t charge, Cache::DeleterFn deleter, ClockHandle** handle,
Cache::Priority priority);
bool Release(Cache::Handle* handle, bool erase_if_last_ref = false) override;
ClockHandle* Lookup(const Slice& key, const UniqueId64x2& hashed_key);
bool Ref(Cache::Handle* handle) override;
bool Release(ClockHandle* handle, bool useful, bool erase_if_last_ref);
void Erase(const Slice& key, uint32_t hash) override;
bool Release(ClockHandle* handle, bool erase_if_last_ref = false);
size_t GetUsage() const override;
bool Ref(ClockHandle* handle);
size_t GetPinnedUsage() const override;
void Erase(const Slice& key, const UniqueId64x2& hashed_key);
size_t GetOccupancyCount() const override;
size_t GetUsage() const;
size_t GetTableAddressCount() const override;
size_t GetPinnedUsage() const;
size_t GetOccupancyCount() const;
size_t GetTableAddressCount() const;
void ApplyToSomeEntries(
const std::function<void(const Slice& key, void* value, size_t charge,
DeleterFn deleter)>& callback,
uint32_t average_entries_per_lock, uint32_t* state) override;
size_t average_entries_per_lock, size_t* state);
void EraseUnRefEntries() override;
void EraseUnRefEntries();
std::string GetPrintableOptions() const override { return std::string{}; }
std::string GetPrintableOptions() const { return std::string{}; }
// SecondaryCache not yet supported
Status Insert(const Slice& key, uint32_t hash, void* value,
Status Insert(const Slice& key, const UniqueId64x2& hashed_key, void* value,
const Cache::CacheItemHelper* helper, size_t charge,
Cache::Handle** handle, Cache::Priority priority) override {
return Insert(key, hash, value, charge, helper->del_cb, handle, priority);
ClockHandle** handle, Cache::Priority priority) {
return Insert(key, hashed_key, value, charge, helper->del_cb, handle,
priority);
}
Cache::Handle* Lookup(const Slice& key, uint32_t hash,
ClockHandle* Lookup(const Slice& key, const UniqueId64x2& hashed_key,
const Cache::CacheItemHelper* /*helper*/,
const Cache::CreateCallback& /*create_cb*/,
Cache::Priority /*priority*/, bool /*wait*/,
Statistics* /*stats*/) override {
return Lookup(key, hash);
Statistics* /*stats*/) {
return Lookup(key, hashed_key);
}
bool IsReady(Cache::Handle* /*handle*/) override { return true; }
bool IsReady(ClockHandle* /*handle*/) { return true; }
void Wait(Cache::Handle* /*handle*/) override {}
void Wait(ClockHandle* /*handle*/) {}
// Acquire/release N references
void TEST_RefN(Cache::Handle* handle, size_t n);
void TEST_ReleaseN(Cache::Handle* handle, size_t n);
void TEST_RefN(ClockHandle* handle, size_t n);
void TEST_ReleaseN(ClockHandle* handle, size_t n);
private: // functions
friend class ClockCache;
friend class ClockCacheTest;
ClockHandle* DetachedInsert(const ClockHandleMoreData& h);
ClockHandle* DetachedInsert(const ClockHandleBasicData& h);
// Returns the number of bits used to hash an element in the hash
// table.
@ -586,35 +611,20 @@ class HyperClockCache
#ifdef NDEBUG
final
#endif
: public ShardedCache {
: public ShardedCache<ClockCacheShard> {
public:
HyperClockCache(size_t capacity, size_t estimated_value_size,
int num_shard_bits, bool strict_capacity_limit,
CacheMetadataChargePolicy metadata_charge_policy =
kDontChargeCacheMetadata);
~HyperClockCache() override;
CacheMetadataChargePolicy metadata_charge_policy,
std::shared_ptr<MemoryAllocator> memory_allocator);
const char* Name() const override { return "HyperClockCache"; }
CacheShard* GetShard(uint32_t shard) override;
const CacheShard* GetShard(uint32_t shard) const override;
void* Value(Handle* handle) override;
size_t GetCharge(Handle* handle) const override;
uint32_t GetHash(Handle* handle) const override;
DeleterFn GetDeleter(Handle* handle) const override;
void DisownData() override;
private:
ClockCacheShard* shards_ = nullptr;
int num_shards_;
}; // class HyperClockCache
} // namespace hyper_clock_cache

92
cache/fast_lru_cache.cc vendored
View File

@ -173,7 +173,7 @@ inline int LRUHandleTable::FindSlot(const Slice& key,
LRUCacheShard::LRUCacheShard(size_t capacity, size_t estimated_value_size,
bool strict_capacity_limit,
CacheMetadataChargePolicy metadata_charge_policy)
: CacheShard(metadata_charge_policy),
: CacheShardBase(metadata_charge_policy),
capacity_(capacity),
strict_capacity_limit_(strict_capacity_limit),
table_(
@ -211,27 +211,27 @@ void LRUCacheShard::EraseUnRefEntries() {
void LRUCacheShard::ApplyToSomeEntries(
const std::function<void(const Slice& key, void* value, size_t charge,
DeleterFn deleter)>& callback,
uint32_t average_entries_per_lock, uint32_t* state) {
size_t average_entries_per_lock, size_t* state) {
// The state is essentially going to be the starting hash, which works
// nicely even if we resize between calls because we use upper-most
// hash bits for table indexes.
DMutexLock l(mutex_);
uint32_t length_bits = table_.GetLengthBits();
uint32_t length = table_.GetTableSize();
size_t length_bits = table_.GetLengthBits();
size_t length = table_.GetTableSize();
assert(average_entries_per_lock > 0);
// Assuming we are called with same average_entries_per_lock repeatedly,
// this simplifies some logic (index_end will not overflow).
assert(average_entries_per_lock < length || *state == 0);
uint32_t index_begin = *state >> (32 - length_bits);
uint32_t index_end = index_begin + average_entries_per_lock;
size_t index_begin = *state >> (sizeof(size_t) * 8u - length_bits);
size_t index_end = index_begin + average_entries_per_lock;
if (index_end >= length) {
// Going to end
index_end = length;
*state = UINT32_MAX;
*state = SIZE_MAX;
} else {
*state = index_end << (32 - length_bits);
*state = index_end << (sizeof(size_t) * 8u - length_bits);
}
table_.ApplyToEntriesRange(
@ -322,8 +322,7 @@ void LRUCacheShard::SetStrictCapacityLimit(bool strict_capacity_limit) {
Status LRUCacheShard::Insert(const Slice& key, uint32_t hash, void* value,
size_t charge, Cache::DeleterFn deleter,
Cache::Handle** handle,
Cache::Priority /*priority*/) {
LRUHandle** handle, Cache::Priority /*priority*/) {
if (key.size() != kCacheKeySize) {
return Status::NotSupported("FastLRUCache only supports key size " +
std::to_string(kCacheKeySize) + "B");
@ -409,7 +408,7 @@ Status LRUCacheShard::Insert(const Slice& key, uint32_t hash, void* value,
if (!h->HasRefs()) {
h->Ref();
}
*handle = reinterpret_cast<Cache::Handle*>(h);
*handle = h;
}
}
}
@ -422,7 +421,7 @@ Status LRUCacheShard::Insert(const Slice& key, uint32_t hash, void* value,
return s;
}
Cache::Handle* LRUCacheShard::Lookup(const Slice& key, uint32_t hash) {
LRUHandle* LRUCacheShard::Lookup(const Slice& key, uint32_t hash) {
LRUHandle* h = nullptr;
{
DMutexLock l(mutex_);
@ -437,23 +436,21 @@ Cache::Handle* LRUCacheShard::Lookup(const Slice& key, uint32_t hash) {
h->Ref();
}
}
return reinterpret_cast<Cache::Handle*>(h);
return h;
}
bool LRUCacheShard::Ref(Cache::Handle* h) {
LRUHandle* e = reinterpret_cast<LRUHandle*>(h);
bool LRUCacheShard::Ref(LRUHandle* h) {
DMutexLock l(mutex_);
// To create another reference - entry must be already externally referenced.
assert(e->HasRefs());
e->Ref();
assert(h->HasRefs());
h->Ref();
return true;
}
bool LRUCacheShard::Release(Cache::Handle* handle, bool erase_if_last_ref) {
if (handle == nullptr) {
bool LRUCacheShard::Release(LRUHandle* h, bool erase_if_last_ref) {
if (h == nullptr) {
return false;
}
LRUHandle* h = reinterpret_cast<LRUHandle*>(handle);
LRUHandle copy;
bool last_reference = false;
{
@ -535,41 +532,18 @@ size_t LRUCacheShard::GetTableAddressCount() const {
return table_.GetTableSize();
}
std::string LRUCacheShard::GetPrintableOptions() const { return std::string{}; }
LRUCache::LRUCache(size_t capacity, size_t estimated_value_size,
int num_shard_bits, bool strict_capacity_limit,
CacheMetadataChargePolicy metadata_charge_policy)
: ShardedCache(capacity, num_shard_bits, strict_capacity_limit) {
: ShardedCache(capacity, num_shard_bits, strict_capacity_limit,
nullptr /*allocator*/) {
assert(estimated_value_size > 0 ||
metadata_charge_policy != kDontChargeCacheMetadata);
num_shards_ = 1 << num_shard_bits;
shards_ = reinterpret_cast<LRUCacheShard*>(
port::cacheline_aligned_alloc(sizeof(LRUCacheShard) * num_shards_));
size_t per_shard = (capacity + (num_shards_ - 1)) / num_shards_;
for (int i = 0; i < num_shards_; i++) {
new (&shards_[i])
LRUCacheShard(per_shard, estimated_value_size, strict_capacity_limit,
metadata_charge_policy);
}
}
LRUCache::~LRUCache() {
if (shards_ != nullptr) {
assert(num_shards_ > 0);
for (int i = 0; i < num_shards_; i++) {
shards_[i].~LRUCacheShard();
}
port::cacheline_aligned_free(shards_);
}
}
CacheShard* LRUCache::GetShard(uint32_t shard) {
return reinterpret_cast<CacheShard*>(&shards_[shard]);
}
const CacheShard* LRUCache::GetShard(uint32_t shard) const {
return reinterpret_cast<CacheShard*>(&shards_[shard]);
size_t per_shard = GetPerShardCapacity();
InitShards([=](LRUCacheShard* cs) {
new (cs) LRUCacheShard(per_shard, estimated_value_size,
strict_capacity_limit, metadata_charge_policy);
});
}
void* LRUCache::Value(Handle* handle) {
@ -577,12 +551,8 @@ void* LRUCache::Value(Handle* handle) {
}
size_t LRUCache::GetCharge(Handle* handle) const {
CacheMetadataChargePolicy metadata_charge_policy = kDontChargeCacheMetadata;
if (num_shards_ > 0) {
metadata_charge_policy = shards_[0].metadata_charge_policy_;
}
return reinterpret_cast<const LRUHandle*>(handle)->GetCharge(
metadata_charge_policy);
GetShard(0).metadata_charge_policy_);
}
Cache::DeleterFn LRUCache::GetDeleter(Handle* handle) const {
@ -590,18 +560,6 @@ Cache::DeleterFn LRUCache::GetDeleter(Handle* handle) const {
return h->deleter;
}
uint32_t LRUCache::GetHash(Handle* handle) const {
return reinterpret_cast<const LRUHandle*>(handle)->hash;
}
void LRUCache::DisownData() {
// Leak data only if that won't generate an ASAN/valgrind warning.
if (!kMustFreeHeapAllocations) {
shards_ = nullptr;
num_shards_ = 0;
}
}
} // namespace fast_lru_cache
std::shared_ptr<Cache> NewFastLRUCache(

75
cache/fast_lru_cache.h vendored
View File

@ -141,6 +141,9 @@ struct LRUHandle {
Slice key() const { return Slice(key_data.data(), kCacheKeySize); }
// For HandleImpl concept
uint32_t GetHash() const { return hash; }
// Increase the reference count by 1.
void Ref() { refs++; }
@ -260,8 +263,8 @@ class LRUHandleTable {
void Assign(int slot, LRUHandle* h);
template <typename T>
void ApplyToEntriesRange(T func, uint32_t index_begin, uint32_t index_end) {
for (uint32_t i = index_begin; i < index_end; i++) {
void ApplyToEntriesRange(T func, size_t index_begin, size_t index_end) {
for (size_t i = index_begin; i < index_end; i++) {
LRUHandle* h = &array_[i];
if (h->IsVisible()) {
func(h);
@ -316,20 +319,30 @@ class LRUHandleTable {
};
// A single shard of sharded cache.
class ALIGN_AS(CACHE_LINE_SIZE) LRUCacheShard final : public CacheShard {
class ALIGN_AS(CACHE_LINE_SIZE) LRUCacheShard final : public CacheShardBase {
public:
LRUCacheShard(size_t capacity, size_t estimated_value_size,
bool strict_capacity_limit,
CacheMetadataChargePolicy metadata_charge_policy);
~LRUCacheShard() override = default;
// For CacheShard concept
using HandleImpl = LRUHandle;
// Keep 32-bit hashing for now (FIXME: upgrade to 64-bit)
using HashVal = uint32_t;
using HashCref = uint32_t;
static inline HashVal ComputeHash(const Slice& key) {
return Lower32of64(GetSliceNPHash64(key));
}
static inline uint32_t HashPieceForSharding(HashCref hash) { return hash; }
// Separate from constructor so caller can easily make an array of LRUCache
// if current usage is more than new capacity, the function will attempt to
// free the needed space.
void SetCapacity(size_t capacity) override;
void SetCapacity(size_t capacity);
// Set the flag to reject insertion if cache if full.
void SetStrictCapacityLimit(bool strict_capacity_limit) override;
void SetStrictCapacityLimit(bool strict_capacity_limit);
// Like Cache methods, but with an extra "hash" parameter.
// Insert an item into the hash table and, if handle is null, insert into
@ -337,48 +350,45 @@ class ALIGN_AS(CACHE_LINE_SIZE) LRUCacheShard final : public CacheShard {
// and free_handle_on_fail is true, the item is deleted and handle is set to
// nullptr.
Status Insert(const Slice& key, uint32_t hash, void* value, size_t charge,
Cache::DeleterFn deleter, Cache::Handle** handle,
Cache::Priority priority) override;
Cache::DeleterFn deleter, LRUHandle** handle,
Cache::Priority priority);
Status Insert(const Slice& key, uint32_t hash, void* value,
const Cache::CacheItemHelper* helper, size_t charge,
Cache::Handle** handle, Cache::Priority priority) override {
LRUHandle** handle, Cache::Priority priority) {
return Insert(key, hash, value, charge, helper->del_cb, handle, priority);
}
Cache::Handle* Lookup(const Slice& key, uint32_t hash,
LRUHandle* Lookup(const Slice& key, uint32_t hash,
const Cache::CacheItemHelper* /*helper*/,
const Cache::CreateCallback& /*create_cb*/,
Cache::Priority /*priority*/, bool /*wait*/,
Statistics* /*stats*/) override {
Statistics* /*stats*/) {
return Lookup(key, hash);
}
Cache::Handle* Lookup(const Slice& key, uint32_t hash) override;
LRUHandle* Lookup(const Slice& key, uint32_t hash);
bool Release(Cache::Handle* handle, bool /*useful*/,
bool erase_if_last_ref) override {
bool Release(LRUHandle* handle, bool /*useful*/, bool erase_if_last_ref) {
return Release(handle, erase_if_last_ref);
}
bool IsReady(Cache::Handle* /*handle*/) override { return true; }
void Wait(Cache::Handle* /*handle*/) override {}
bool IsReady(LRUHandle* /*handle*/) { return true; }
void Wait(LRUHandle* /*handle*/) {}
bool Ref(Cache::Handle* handle) override;
bool Release(Cache::Handle* handle, bool erase_if_last_ref = false) override;
void Erase(const Slice& key, uint32_t hash) override;
bool Ref(LRUHandle* handle);
bool Release(LRUHandle* handle, bool erase_if_last_ref = false);
void Erase(const Slice& key, uint32_t hash);
size_t GetUsage() const override;
size_t GetPinnedUsage() const override;
size_t GetOccupancyCount() const override;
size_t GetTableAddressCount() const override;
size_t GetUsage() const;
size_t GetPinnedUsage() const;
size_t GetOccupancyCount() const;
size_t GetTableAddressCount() const;
void ApplyToSomeEntries(
const std::function<void(const Slice& key, void* value, size_t charge,
DeleterFn deleter)>& callback,
uint32_t average_entries_per_lock, uint32_t* state) override;
size_t average_entries_per_lock, size_t* state);
void EraseUnRefEntries() override;
std::string GetPrintableOptions() const override;
void EraseUnRefEntries();
private:
friend class LRUCache;
@ -446,25 +456,16 @@ class LRUCache
#ifdef NDEBUG
final
#endif
: public ShardedCache {
: public ShardedCache<LRUCacheShard> {
public:
LRUCache(size_t capacity, size_t estimated_value_size, int num_shard_bits,
bool strict_capacity_limit,
CacheMetadataChargePolicy metadata_charge_policy =
kDontChargeCacheMetadata);
~LRUCache() override;
const char* Name() const override { return "LRUCache"; }
CacheShard* GetShard(uint32_t shard) override;
const CacheShard* GetShard(uint32_t shard) const override;
void* Value(Handle* handle) override;
size_t GetCharge(Handle* handle) const override;
uint32_t GetHash(Handle* handle) const override;
DeleterFn GetDeleter(Handle* handle) const override;
void DisownData() override;
private:
LRUCacheShard* shards_ = nullptr;
int num_shards_ = 0;
};
} // namespace fast_lru_cache

144
cache/lru_cache.cc vendored
View File

@ -38,7 +38,7 @@ LRUHandleTable::~LRUHandleTable() {
h->Free();
}
},
0, uint32_t{1} << length_bits_);
0, size_t{1} << length_bits_);
}
LRUHandle* LRUHandleTable::Lookup(const Slice& key, uint32_t hash) {
@ -113,12 +113,13 @@ void LRUHandleTable::Resize() {
length_bits_ = new_length_bits;
}
LRUCacheShard::LRUCacheShard(
size_t capacity, bool strict_capacity_limit, double high_pri_pool_ratio,
LRUCacheShard::LRUCacheShard(size_t capacity, bool strict_capacity_limit,
double high_pri_pool_ratio,
double low_pri_pool_ratio, bool use_adaptive_mutex,
CacheMetadataChargePolicy metadata_charge_policy, int max_upper_hash_bits,
const std::shared_ptr<SecondaryCache>& secondary_cache)
: CacheShard(metadata_charge_policy),
CacheMetadataChargePolicy metadata_charge_policy,
int max_upper_hash_bits,
SecondaryCache* secondary_cache)
: CacheShardBase(metadata_charge_policy),
capacity_(0),
high_pri_pool_usage_(0),
low_pri_pool_usage_(0),
@ -165,27 +166,27 @@ void LRUCacheShard::EraseUnRefEntries() {
void LRUCacheShard::ApplyToSomeEntries(
const std::function<void(const Slice& key, void* value, size_t charge,
DeleterFn deleter)>& callback,
uint32_t average_entries_per_lock, uint32_t* state) {
size_t average_entries_per_lock, size_t* state) {
// The state is essentially going to be the starting hash, which works
// nicely even if we resize between calls because we use upper-most
// hash bits for table indexes.
DMutexLock l(mutex_);
uint32_t length_bits = table_.GetLengthBits();
uint32_t length = uint32_t{1} << length_bits;
int length_bits = table_.GetLengthBits();
size_t length = size_t{1} << length_bits;
assert(average_entries_per_lock > 0);
// Assuming we are called with same average_entries_per_lock repeatedly,
// this simplifies some logic (index_end will not overflow).
assert(average_entries_per_lock < length || *state == 0);
uint32_t index_begin = *state >> (32 - length_bits);
uint32_t index_end = index_begin + average_entries_per_lock;
size_t index_begin = *state >> (sizeof(size_t) * 8u - length_bits);
size_t index_end = index_begin + average_entries_per_lock;
if (index_end >= length) {
// Going to end
index_end = length;
*state = UINT32_MAX;
*state = SIZE_MAX;
} else {
*state = index_end << (32 - length_bits);
*state = index_end << (sizeof(size_t) * 8u - length_bits);
}
table_.ApplyToEntriesRange(
@ -364,7 +365,7 @@ void LRUCacheShard::SetStrictCapacityLimit(bool strict_capacity_limit) {
strict_capacity_limit_ = strict_capacity_limit;
}
Status LRUCacheShard::InsertItem(LRUHandle* e, Cache::Handle** handle,
Status LRUCacheShard::InsertItem(LRUHandle* e, LRUHandle** handle,
bool free_handle_on_fail) {
Status s = Status::OK();
autovector<LRUHandle*> last_reference_list;
@ -414,7 +415,7 @@ Status LRUCacheShard::InsertItem(LRUHandle* e, Cache::Handle** handle,
if (!e->HasRefs()) {
e->Ref();
}
*handle = reinterpret_cast<Cache::Handle*>(e);
*handle = e;
}
}
}
@ -480,7 +481,7 @@ void LRUCacheShard::Promote(LRUHandle* e) {
priority);
} else {
e->SetInCache(true);
Cache::Handle* handle = reinterpret_cast<Cache::Handle*>(e);
LRUHandle* handle = e;
// This InsertItem() could fail if the cache is over capacity and
// strict_capacity_limit_ is true. In such a case, we don't want
// InsertItem() to free the handle, since the item is already in memory
@ -505,11 +506,11 @@ void LRUCacheShard::Promote(LRUHandle* e) {
}
}
Cache::Handle* LRUCacheShard::Lookup(
const Slice& key, uint32_t hash,
const ShardedCache::CacheItemHelper* helper,
const ShardedCache::CreateCallback& create_cb, Cache::Priority priority,
bool wait, Statistics* stats) {
LRUHandle* LRUCacheShard::Lookup(const Slice& key, uint32_t hash,
const Cache::CacheItemHelper* helper,
const Cache::CreateCallback& create_cb,
Cache::Priority priority, bool wait,
Statistics* stats) {
LRUHandle* e = nullptr;
bool found_dummy_entry{false};
{
@ -607,11 +608,10 @@ Cache::Handle* LRUCacheShard::Lookup(
assert(e == nullptr);
}
}
return reinterpret_cast<Cache::Handle*>(e);
return e;
}
bool LRUCacheShard::Ref(Cache::Handle* h) {
LRUHandle* e = reinterpret_cast<LRUHandle*>(h);
bool LRUCacheShard::Ref(LRUHandle* e) {
DMutexLock l(mutex_);
// To create another reference - entry must be already externally referenced.
assert(e->HasRefs());
@ -635,11 +635,11 @@ void LRUCacheShard::SetLowPriorityPoolRatio(double low_pri_pool_ratio) {
MaintainPoolSize();
}
bool LRUCacheShard::Release(Cache::Handle* handle, bool erase_if_last_ref) {
if (handle == nullptr) {
bool LRUCacheShard::Release(LRUHandle* e, bool /*useful*/,
bool erase_if_last_ref) {
if (e == nullptr) {
return false;
}
LRUHandle* e = reinterpret_cast<LRUHandle*>(handle);
bool last_reference = false;
// Must Wait or WaitAll first on pending handles. Otherwise, would leak
// a secondary cache handle.
@ -679,7 +679,7 @@ Status LRUCacheShard::Insert(const Slice& key, uint32_t hash, void* value,
size_t charge,
void (*deleter)(const Slice& key, void* value),
const Cache::CacheItemHelper* helper,
Cache::Handle** handle, Cache::Priority priority) {
LRUHandle** handle, Cache::Priority priority) {
// Allocate the memory here outside of the mutex.
// If the cache is full, we'll have to release it.
// It shouldn't happen very often though.
@ -738,8 +738,7 @@ void LRUCacheShard::Erase(const Slice& key, uint32_t hash) {
}
}
bool LRUCacheShard::IsReady(Cache::Handle* handle) {
LRUHandle* e = reinterpret_cast<LRUHandle*>(handle);
bool LRUCacheShard::IsReady(LRUHandle* e) {
bool ready = true;
if (e->IsPending()) {
assert(secondary_cache_);
@ -770,7 +769,7 @@ size_t LRUCacheShard::GetTableAddressCount() const {
return size_t{1} << table_.GetLengthBits();
}
std::string LRUCacheShard::GetPrintableOptions() const {
void LRUCacheShard::AppendPrintableOptions(std::string& str) const {
const int kBufferSize = 200;
char buffer[kBufferSize];
{
@ -780,7 +779,7 @@ std::string LRUCacheShard::GetPrintableOptions() const {
snprintf(buffer + strlen(buffer), kBufferSize - strlen(buffer),
" low_pri_pool_ratio: %.3lf\n", low_pri_pool_ratio_);
}
return std::string(buffer);
str.append(buffer);
}
LRUCache::LRUCache(size_t capacity, int num_shard_bits,
@ -789,38 +788,18 @@ LRUCache::LRUCache(size_t capacity, int num_shard_bits,
std::shared_ptr<MemoryAllocator> allocator,
bool use_adaptive_mutex,
CacheMetadataChargePolicy metadata_charge_policy,
const std::shared_ptr<SecondaryCache>& secondary_cache)
std::shared_ptr<SecondaryCache> _secondary_cache)
: ShardedCache(capacity, num_shard_bits, strict_capacity_limit,
std::move(allocator)) {
num_shards_ = 1 << num_shard_bits;
shards_ = reinterpret_cast<LRUCacheShard*>(
port::cacheline_aligned_alloc(sizeof(LRUCacheShard) * num_shards_));
size_t per_shard = (capacity + (num_shards_ - 1)) / num_shards_;
for (int i = 0; i < num_shards_; i++) {
new (&shards_[i]) LRUCacheShard(
std::move(allocator)),
secondary_cache_(std::move(_secondary_cache)) {
size_t per_shard = GetPerShardCapacity();
SecondaryCache* secondary_cache = secondary_cache_.get();
InitShards([=](LRUCacheShard* cs) {
new (cs) LRUCacheShard(
per_shard, strict_capacity_limit, high_pri_pool_ratio,
low_pri_pool_ratio, use_adaptive_mutex, metadata_charge_policy,
/* max_upper_hash_bits */ 32 - num_shard_bits, secondary_cache);
}
secondary_cache_ = secondary_cache;
}
LRUCache::~LRUCache() {
if (shards_ != nullptr) {
assert(num_shards_ > 0);
for (int i = 0; i < num_shards_; i++) {
shards_[i].~LRUCacheShard();
}
port::cacheline_aligned_free(shards_);
}
}
CacheShard* LRUCache::GetShard(uint32_t shard) {
return reinterpret_cast<CacheShard*>(&shards_[shard]);
}
const CacheShard* LRUCache::GetShard(uint32_t shard) const {
return reinterpret_cast<CacheShard*>(&shards_[shard]);
});
}
void* LRUCache::Value(Handle* handle) {
@ -831,12 +810,8 @@ void* LRUCache::Value(Handle* handle) {
}
size_t LRUCache::GetCharge(Handle* handle) const {
CacheMetadataChargePolicy metadata_charge_policy = kDontChargeCacheMetadata;
if (num_shards_ > 0) {
metadata_charge_policy = shards_[0].metadata_charge_policy_;
}
return reinterpret_cast<const LRUHandle*>(handle)->GetCharge(
metadata_charge_policy);
GetShard(0).metadata_charge_policy_);
}
Cache::DeleterFn LRUCache::GetDeleter(Handle* handle) const {
@ -848,32 +823,12 @@ Cache::DeleterFn LRUCache::GetDeleter(Handle* handle) const {
}
}
uint32_t LRUCache::GetHash(Handle* handle) const {
return reinterpret_cast<const LRUHandle*>(handle)->hash;
}
void LRUCache::DisownData() {
// Leak data only if that won't generate an ASAN/valgrind warning.
if (!kMustFreeHeapAllocations) {
shards_ = nullptr;
num_shards_ = 0;
}
}
size_t LRUCache::TEST_GetLRUSize() {
size_t lru_size_of_all_shards = 0;
for (int i = 0; i < num_shards_; i++) {
lru_size_of_all_shards += shards_[i].TEST_GetLRUSize();
}
return lru_size_of_all_shards;
return SumOverShards([](LRUCacheShard& cs) { return cs.TEST_GetLRUSize(); });
}
double LRUCache::GetHighPriPoolRatio() {
double result = 0.0;
if (num_shards_ > 0) {
result = shards_[0].GetHighPriPoolRatio();
}
return result;
return GetShard(0).GetHighPriPoolRatio();
}
void LRUCache::WaitAll(std::vector<Handle*>& handles) {
@ -899,22 +854,17 @@ void LRUCache::WaitAll(std::vector<Handle*>& handles) {
if (!lru_handle->IsPending()) {
continue;
}
uint32_t hash = GetHash(handle);
LRUCacheShard* shard = static_cast<LRUCacheShard*>(GetShard(Shard(hash)));
shard->Promote(lru_handle);
GetShard(lru_handle->hash).Promote(lru_handle);
}
}
}
std::string LRUCache::GetPrintableOptions() const {
std::string ret;
ret.reserve(20000);
ret.append(ShardedCache::GetPrintableOptions());
void LRUCache::AppendPrintableOptions(std::string& str) const {
ShardedCache::AppendPrintableOptions(str); // options from shard
if (secondary_cache_) {
ret.append(" secondary_cache:\n");
ret.append(secondary_cache_->GetPrintableOptions());
str.append(" secondary_cache:\n");
str.append(secondary_cache_->GetPrintableOptions());
}
return ret;
}
} // namespace lru_cache

118
cache/lru_cache.h vendored
View File

@ -53,7 +53,7 @@ struct LRUHandle {
Info() {}
~Info() {}
Cache::DeleterFn deleter;
const ShardedCache::CacheItemHelper* helper;
const Cache::CacheItemHelper* helper;
} info_;
// An entry is not added to the LRUHandleTable until the secondary cache
// lookup is complete, so its safe to have this union.
@ -108,6 +108,9 @@ struct LRUHandle {
Slice key() const { return Slice(key_data, key_length); }
// For HandleImpl concept
uint32_t GetHash() const { return hash; }
// Increase the reference count by 1.
void Ref() { refs++; }
@ -262,9 +265,6 @@ struct LRUHandle {
// 4.4.3's builtin hashtable.
class LRUHandleTable {
public:
// If the table uses more hash bits than `max_upper_hash_bits`,
// it will eat into the bits used for sharding, which are constant
// for a given LRUHandleTable.
explicit LRUHandleTable(int max_upper_hash_bits);
~LRUHandleTable();
@ -273,8 +273,8 @@ class LRUHandleTable {
LRUHandle* Remove(const Slice& key, uint32_t hash);
template <typename T>
void ApplyToEntriesRange(T func, uint32_t index_begin, uint32_t index_end) {
for (uint32_t i = index_begin; i < index_end; i++) {
void ApplyToEntriesRange(T func, size_t index_begin, size_t index_end) {
for (size_t i = index_begin; i < index_end; i++) {
LRUHandle* h = list_[i];
while (h != nullptr) {
auto n = h->next_hash;
@ -313,23 +313,31 @@ class LRUHandleTable {
};
// A single shard of sharded cache.
class ALIGN_AS(CACHE_LINE_SIZE) LRUCacheShard final : public CacheShard {
class ALIGN_AS(CACHE_LINE_SIZE) LRUCacheShard final : public CacheShardBase {
public:
LRUCacheShard(size_t capacity, bool strict_capacity_limit,
double high_pri_pool_ratio, double low_pri_pool_ratio,
bool use_adaptive_mutex,
CacheMetadataChargePolicy metadata_charge_policy,
int max_upper_hash_bits,
const std::shared_ptr<SecondaryCache>& secondary_cache);
virtual ~LRUCacheShard() override = default;
int max_upper_hash_bits, SecondaryCache* secondary_cache);
public: // Type definitions expected as parameter to ShardedCache
using HandleImpl = LRUHandle;
using HashVal = uint32_t;
using HashCref = uint32_t;
public: // Function definitions expected as parameter to ShardedCache
static inline HashVal ComputeHash(const Slice& key) {
return Lower32of64(GetSliceNPHash64(key));
}
// Separate from constructor so caller can easily make an array of LRUCache
// if current usage is more than new capacity, the function will attempt to
// free the needed space.
virtual void SetCapacity(size_t capacity) override;
void SetCapacity(size_t capacity);
// Set the flag to reject insertion if cache if full.
virtual void SetStrictCapacityLimit(bool strict_capacity_limit) override;
void SetStrictCapacityLimit(bool strict_capacity_limit);
// Set percentage of capacity reserved for high-pri cache entries.
void SetHighPriorityPoolRatio(double high_pri_pool_ratio);
@ -338,58 +346,49 @@ class ALIGN_AS(CACHE_LINE_SIZE) LRUCacheShard final : public CacheShard {
void SetLowPriorityPoolRatio(double low_pri_pool_ratio);
// Like Cache methods, but with an extra "hash" parameter.
virtual Status Insert(const Slice& key, uint32_t hash, void* value,
inline Status Insert(const Slice& key, uint32_t hash, void* value,
size_t charge, Cache::DeleterFn deleter,
Cache::Handle** handle,
Cache::Priority priority) override {
LRUHandle** handle, Cache::Priority priority) {
return Insert(key, hash, value, charge, deleter, nullptr, handle, priority);
}
virtual Status Insert(const Slice& key, uint32_t hash, void* value,
inline Status Insert(const Slice& key, uint32_t hash, void* value,
const Cache::CacheItemHelper* helper, size_t charge,
Cache::Handle** handle,
Cache::Priority priority) override {
LRUHandle** handle, Cache::Priority priority) {
assert(helper);
return Insert(key, hash, value, charge, nullptr, helper, handle, priority);
}
// If helper_cb is null, the values of the following arguments don't matter.
virtual Cache::Handle* Lookup(const Slice& key, uint32_t hash,
const ShardedCache::CacheItemHelper* helper,
const ShardedCache::CreateCallback& create_cb,
ShardedCache::Priority priority, bool wait,
Statistics* stats) override;
virtual Cache::Handle* Lookup(const Slice& key, uint32_t hash) override {
LRUHandle* Lookup(const Slice& key, uint32_t hash,
const Cache::CacheItemHelper* helper,
const Cache::CreateCallback& create_cb,
Cache::Priority priority, bool wait, Statistics* stats);
inline LRUHandle* Lookup(const Slice& key, uint32_t hash) {
return Lookup(key, hash, nullptr, nullptr, Cache::Priority::LOW, true,
nullptr);
}
virtual bool Release(Cache::Handle* handle, bool /*useful*/,
bool erase_if_last_ref) override {
return Release(handle, erase_if_last_ref);
}
virtual bool IsReady(Cache::Handle* /*handle*/) override;
virtual void Wait(Cache::Handle* /*handle*/) override {}
virtual bool Ref(Cache::Handle* handle) override;
virtual bool Release(Cache::Handle* handle,
bool erase_if_last_ref = false) override;
virtual void Erase(const Slice& key, uint32_t hash) override;
bool Release(LRUHandle* handle, bool useful, bool erase_if_last_ref);
bool IsReady(LRUHandle* /*handle*/);
void Wait(LRUHandle* /*handle*/) {}
bool Ref(LRUHandle* handle);
void Erase(const Slice& key, uint32_t hash);
// Although in some platforms the update of size_t is atomic, to make sure
// GetUsage() and GetPinnedUsage() work correctly under any platform, we'll
// protect them with mutex_.
virtual size_t GetUsage() const override;
virtual size_t GetPinnedUsage() const override;
virtual size_t GetOccupancyCount() const override;
virtual size_t GetTableAddressCount() const override;
size_t GetUsage() const;
size_t GetPinnedUsage() const;
size_t GetOccupancyCount() const;
size_t GetTableAddressCount() const;
virtual void ApplyToSomeEntries(
void ApplyToSomeEntries(
const std::function<void(const Slice& key, void* value, size_t charge,
DeleterFn deleter)>& callback,
uint32_t average_entries_per_lock, uint32_t* state) override;
size_t average_entries_per_lock, size_t* state);
virtual void EraseUnRefEntries() override;
virtual std::string GetPrintableOptions() const override;
void EraseUnRefEntries();
public: // other function definitions
void TEST_GetLRUList(LRUHandle** lru, LRUHandle** lru_low_pri,
LRUHandle** lru_bottom_pri);
@ -403,17 +402,19 @@ class ALIGN_AS(CACHE_LINE_SIZE) LRUCacheShard final : public CacheShard {
// Retrieves low pri pool ratio
double GetLowPriPoolRatio();
void AppendPrintableOptions(std::string& /*str*/) const;
private:
friend class LRUCache;
// Insert an item into the hash table and, if handle is null, insert into
// the LRU list. Older items are evicted as necessary. If the cache is full
// and free_handle_on_fail is true, the item is deleted and handle is set to
// nullptr.
Status InsertItem(LRUHandle* item, Cache::Handle** handle,
Status InsertItem(LRUHandle* item, LRUHandle** handle,
bool free_handle_on_fail);
Status Insert(const Slice& key, uint32_t hash, void* value, size_t charge,
DeleterFn deleter, const Cache::CacheItemHelper* helper,
Cache::Handle** handle, Cache::Priority priority);
LRUHandle** handle, Cache::Priority priority);
// Promote an item looked up from the secondary cache to the LRU cache.
// The item may be still in the secondary cache.
// It is only inserted into the hash table and not the LRU list, and only
@ -500,14 +501,15 @@ class ALIGN_AS(CACHE_LINE_SIZE) LRUCacheShard final : public CacheShard {
// don't mind mutex_ invoking the non-const actions.
mutable DMutex mutex_;
std::shared_ptr<SecondaryCache> secondary_cache_;
// Owned by LRUCache
SecondaryCache* secondary_cache_;
};
class LRUCache
#ifdef NDEBUG
final
#endif
: public ShardedCache {
: public ShardedCache<LRUCacheShard> {
public:
LRUCache(size_t capacity, int num_shard_bits, bool strict_capacity_limit,
double high_pri_pool_ratio, double low_pri_pool_ratio,
@ -515,27 +517,21 @@ class LRUCache
bool use_adaptive_mutex = kDefaultToAdaptiveMutex,
CacheMetadataChargePolicy metadata_charge_policy =
kDontChargeCacheMetadata,
const std::shared_ptr<SecondaryCache>& secondary_cache = nullptr);
virtual ~LRUCache();
virtual const char* Name() const override { return "LRUCache"; }
virtual CacheShard* GetShard(uint32_t shard) override;
virtual const CacheShard* GetShard(uint32_t shard) const override;
virtual void* Value(Handle* handle) override;
virtual size_t GetCharge(Handle* handle) const override;
virtual uint32_t GetHash(Handle* handle) const override;
virtual DeleterFn GetDeleter(Handle* handle) const override;
virtual void DisownData() override;
virtual void WaitAll(std::vector<Handle*>& handles) override;
std::string GetPrintableOptions() const override;
std::shared_ptr<SecondaryCache> secondary_cache = nullptr);
const char* Name() const override { return "LRUCache"; }
void* Value(Handle* handle) override;
size_t GetCharge(Handle* handle) const override;
DeleterFn GetDeleter(Handle* handle) const override;
void WaitAll(std::vector<Handle*>& handles) override;
// Retrieves number of elements in LRU, for unit test purpose only.
size_t TEST_GetLRUSize();
// Retrieves high pri pool ratio.
double GetHighPriPoolRatio();
void AppendPrintableOptions(std::string& str) const override;
private:
LRUCacheShard* shards_ = nullptr;
int num_shards_ = 0;
std::shared_ptr<SecondaryCache> secondary_cache_;
};

156
cache/lru_cache_test.cc vendored
View File

@ -67,7 +67,7 @@ class LRUCacheTest : public testing::Test {
bool Lookup(const std::string& key) {
auto handle = cache_->Lookup(key, 0 /*hash*/);
if (handle) {
cache_->Release(handle);
cache_->Release(handle, true /*useful*/, false /*erase*/);
return true;
}
return false;
@ -529,22 +529,27 @@ class ClockCacheTest : public testing::Test {
kDontChargeCacheMetadata);
}
Status Insert(const std::string& key,
Status Insert(const UniqueId64x2& hashed_key,
Cache::Priority priority = Cache::Priority::LOW) {
return shard_->Insert(key, 0 /*hash*/, nullptr /*value*/, 1 /*charge*/,
nullptr /*deleter*/, nullptr /*handle*/, priority);
return shard_->Insert(TestKey(hashed_key), hashed_key, nullptr /*value*/,
1 /*charge*/, nullptr /*deleter*/, nullptr /*handle*/,
priority);
}
Status Insert(char key, Cache::Priority priority = Cache::Priority::LOW) {
return Insert(std::string(kCacheKeySize, key), priority);
return Insert(TestHashedKey(key), priority);
}
Status InsertWithLen(char key, size_t len) {
return Insert(std::string(len, key));
std::string skey(len, key);
return shard_->Insert(skey, TestHashedKey(key), nullptr /*value*/,
1 /*charge*/, nullptr /*deleter*/, nullptr /*handle*/,
Cache::Priority::LOW);
}
bool Lookup(const std::string& key, bool useful = true) {
auto handle = shard_->Lookup(key, 0 /*hash*/);
bool Lookup(const Slice& key, const UniqueId64x2& hashed_key,
bool useful = true) {
auto handle = shard_->Lookup(key, hashed_key);
if (handle) {
shard_->Release(handle, useful, /*erase_if_last_ref=*/false);
return true;
@ -552,44 +557,29 @@ class ClockCacheTest : public testing::Test {
return false;
}
bool Lookup(const UniqueId64x2& hashed_key, bool useful = true) {
return Lookup(TestKey(hashed_key), hashed_key, useful);
}
bool Lookup(char key, bool useful = true) {
return Lookup(std::string(kCacheKeySize, key), useful);
return Lookup(TestHashedKey(key), useful);
}
void Erase(const std::string& key) { shard_->Erase(key, 0 /*hash*/); }
#if 0 // FIXME
size_t CalcEstimatedHandleChargeWrapper(
size_t estimated_value_size,
CacheMetadataChargePolicy metadata_charge_policy) {
return ClockCacheShard::CalcEstimatedHandleCharge(estimated_value_size,
metadata_charge_policy);
void Erase(char key) {
UniqueId64x2 hashed_key = TestHashedKey(key);
shard_->Erase(TestKey(hashed_key), hashed_key);
}
int CalcHashBitsWrapper(size_t capacity, size_t estimated_value_size,
CacheMetadataChargePolicy metadata_charge_policy) {
return ClockCacheShard::CalcHashBits(capacity, estimated_value_size,
metadata_charge_policy);
static inline Slice TestKey(const UniqueId64x2& hashed_key) {
return Slice(reinterpret_cast<const char*>(&hashed_key), 16U);
}
// Maximum number of items that a shard can hold.
double CalcMaxOccupancy(size_t capacity, size_t estimated_value_size,
CacheMetadataChargePolicy metadata_charge_policy) {
size_t handle_charge = ClockCacheShard::CalcEstimatedHandleCharge(
estimated_value_size, metadata_charge_policy);
return capacity / (kLoadFactor * handle_charge);
static inline UniqueId64x2 TestHashedKey(char key) {
// For testing hash near-collision behavior, put the variance in
// hashed_key in bits that are unlikely to be used as hash bits.
return {(static_cast<uint64_t>(key) << 56) + 1234U, 5678U};
}
bool TableSizeIsAppropriate(int hash_bits, double max_occupancy) {
if (hash_bits == 0) {
return max_occupancy <= 1;
} else {
return (1 << hash_bits >= max_occupancy) &&
(1 << (hash_bits - 1) <= max_occupancy);
}
}
#endif
ClockCacheShard* shard_ = nullptr;
};
@ -607,10 +597,10 @@ TEST_F(ClockCacheTest, Misc) {
// Some of this is motivated by code coverage
std::string wrong_size_key(15, 'x');
EXPECT_FALSE(Lookup(wrong_size_key));
EXPECT_FALSE(Lookup(wrong_size_key, TestHashedKey('x')));
EXPECT_FALSE(shard_->Ref(nullptr));
EXPECT_FALSE(shard_->Release(nullptr));
shard_->Erase(wrong_size_key, /*hash*/ 42); // no-op
shard_->Erase(wrong_size_key, TestHashedKey('x')); // no-op
}
TEST_F(ClockCacheTest, Limits) {
@ -622,11 +612,11 @@ TEST_F(ClockCacheTest, Limits) {
// Also tests switching between strict limit and not
shard_->SetStrictCapacityLimit(strict_capacity_limit);
std::string key(16, 'x');
UniqueId64x2 hkey = TestHashedKey('x');
// Single entry charge beyond capacity
{
Status s = shard_->Insert(key, 0 /*hash*/, nullptr /*value*/,
Status s = shard_->Insert(TestKey(hkey), hkey, nullptr /*value*/,
5 /*charge*/, nullptr /*deleter*/,
nullptr /*handle*/, Cache::Priority::LOW);
if (strict_capacity_limit) {
@ -638,9 +628,10 @@ TEST_F(ClockCacheTest, Limits) {
// Single entry fills capacity
{
Cache::Handle* h;
ASSERT_OK(shard_->Insert(key, 0 /*hash*/, nullptr /*value*/, 3 /*charge*/,
nullptr /*deleter*/, &h, Cache::Priority::LOW));
ClockHandle* h;
ASSERT_OK(shard_->Insert(TestKey(hkey), hkey, nullptr /*value*/,
3 /*charge*/, nullptr /*deleter*/, &h,
Cache::Priority::LOW));
// Try to insert more
Status s = Insert('a');
if (strict_capacity_limit) {
@ -657,11 +648,11 @@ TEST_F(ClockCacheTest, Limits) {
// entries) to exceed occupancy limit.
{
size_t n = shard_->GetTableAddressCount() + 1;
std::unique_ptr<Cache::Handle* []> ha { new Cache::Handle* [n] {} };
std::unique_ptr<ClockHandle* []> ha { new ClockHandle* [n] {} };
Status s;
for (size_t i = 0; i < n && s.ok(); ++i) {
EncodeFixed64(&key[0], i);
s = shard_->Insert(key, 0 /*hash*/, nullptr /*value*/, 0 /*charge*/,
hkey[1] = i;
s = shard_->Insert(TestKey(hkey), hkey, nullptr /*value*/, 0 /*charge*/,
nullptr /*deleter*/, &ha[i], Cache::Priority::LOW);
if (i == 0) {
EXPECT_OK(s);
@ -807,12 +798,11 @@ void IncrementIntDeleter(const Slice& /*key*/, void* value) {
// Testing calls to CorrectNearOverflow in Release
TEST_F(ClockCacheTest, ClockCounterOverflowTest) {
NewShard(6, /*strict_capacity_limit*/ false);
Cache::Handle* h;
ClockHandle* h;
int deleted = 0;
std::string my_key(kCacheKeySize, 'x');
uint32_t my_hash = 42;
ASSERT_OK(shard_->Insert(my_key, my_hash, &deleted, 1, IncrementIntDeleter,
&h, Cache::Priority::HIGH));
UniqueId64x2 hkey = TestHashedKey('x');
ASSERT_OK(shard_->Insert(TestKey(hkey), hkey, &deleted, 1,
IncrementIntDeleter, &h, Cache::Priority::HIGH));
// Some large number outstanding
shard_->TEST_RefN(h, 123456789);
@ -822,7 +812,7 @@ TEST_F(ClockCacheTest, ClockCounterOverflowTest) {
shard_->TEST_ReleaseN(h, 1234567);
}
// Mark it invisible (to reach a different CorrectNearOverflow() in Release)
shard_->Erase(my_key, my_hash);
shard_->Erase(TestKey(hkey), hkey);
// Simulate many more lookup/ref + release (one-by-one would be too
// expensive for unit test)
for (int i = 0; i < 10000; ++i) {
@ -844,63 +834,65 @@ TEST_F(ClockCacheTest, ClockCounterOverflowTest) {
TEST_F(ClockCacheTest, CollidingInsertEraseTest) {
NewShard(6, /*strict_capacity_limit*/ false);
int deleted = 0;
std::string key1(kCacheKeySize, 'x');
std::string key2(kCacheKeySize, 'y');
std::string key3(kCacheKeySize, 'z');
uint32_t my_hash = 42;
Cache::Handle* h1;
ASSERT_OK(shard_->Insert(key1, my_hash, &deleted, 1, IncrementIntDeleter, &h1,
UniqueId64x2 hkey1 = TestHashedKey('x');
Slice key1 = TestKey(hkey1);
UniqueId64x2 hkey2 = TestHashedKey('y');
Slice key2 = TestKey(hkey2);
UniqueId64x2 hkey3 = TestHashedKey('z');
Slice key3 = TestKey(hkey3);
ClockHandle* h1;
ASSERT_OK(shard_->Insert(key1, hkey1, &deleted, 1, IncrementIntDeleter, &h1,
Cache::Priority::HIGH));
Cache::Handle* h2;
ASSERT_OK(shard_->Insert(key2, my_hash, &deleted, 1, IncrementIntDeleter, &h2,
ClockHandle* h2;
ASSERT_OK(shard_->Insert(key2, hkey2, &deleted, 1, IncrementIntDeleter, &h2,
Cache::Priority::HIGH));
Cache::Handle* h3;
ASSERT_OK(shard_->Insert(key3, my_hash, &deleted, 1, IncrementIntDeleter, &h3,
ClockHandle* h3;
ASSERT_OK(shard_->Insert(key3, hkey3, &deleted, 1, IncrementIntDeleter, &h3,
Cache::Priority::HIGH));
// Can repeatedly lookup+release despite the hash collision
Cache::Handle* tmp_h;
ClockHandle* tmp_h;
for (bool erase_if_last_ref : {true, false}) { // but not last ref
tmp_h = shard_->Lookup(key1, my_hash);
tmp_h = shard_->Lookup(key1, hkey1);
ASSERT_EQ(h1, tmp_h);
ASSERT_FALSE(shard_->Release(tmp_h, erase_if_last_ref));
tmp_h = shard_->Lookup(key2, my_hash);
tmp_h = shard_->Lookup(key2, hkey2);
ASSERT_EQ(h2, tmp_h);
ASSERT_FALSE(shard_->Release(tmp_h, erase_if_last_ref));
tmp_h = shard_->Lookup(key3, my_hash);
tmp_h = shard_->Lookup(key3, hkey3);
ASSERT_EQ(h3, tmp_h);
ASSERT_FALSE(shard_->Release(tmp_h, erase_if_last_ref));
}
// Make h1 invisible
shard_->Erase(key1, my_hash);
shard_->Erase(key1, hkey1);
// Redundant erase
shard_->Erase(key1, my_hash);
shard_->Erase(key1, hkey1);
// All still alive
ASSERT_EQ(deleted, 0);
// Invisible to Lookup
tmp_h = shard_->Lookup(key1, my_hash);
tmp_h = shard_->Lookup(key1, hkey1);
ASSERT_EQ(nullptr, tmp_h);
// Can still find h2, h3
for (bool erase_if_last_ref : {true, false}) { // but not last ref
tmp_h = shard_->Lookup(key2, my_hash);
tmp_h = shard_->Lookup(key2, hkey2);
ASSERT_EQ(h2, tmp_h);
ASSERT_FALSE(shard_->Release(tmp_h, erase_if_last_ref));
tmp_h = shard_->Lookup(key3, my_hash);
tmp_h = shard_->Lookup(key3, hkey3);
ASSERT_EQ(h3, tmp_h);
ASSERT_FALSE(shard_->Release(tmp_h, erase_if_last_ref));
}
// Also Insert with invisible entry there
ASSERT_OK(shard_->Insert(key1, my_hash, &deleted, 1, IncrementIntDeleter,
ASSERT_OK(shard_->Insert(key1, hkey1, &deleted, 1, IncrementIntDeleter,
nullptr, Cache::Priority::HIGH));
tmp_h = shard_->Lookup(key1, my_hash);
tmp_h = shard_->Lookup(key1, hkey1);
// Found but distinct handle
ASSERT_NE(nullptr, tmp_h);
ASSERT_NE(h1, tmp_h);
@ -918,11 +910,11 @@ TEST_F(ClockCacheTest, CollidingInsertEraseTest) {
// Can still find h2, h3
for (bool erase_if_last_ref : {true, false}) { // but not last ref
tmp_h = shard_->Lookup(key2, my_hash);
tmp_h = shard_->Lookup(key2, hkey2);
ASSERT_EQ(h2, tmp_h);
ASSERT_FALSE(shard_->Release(tmp_h, erase_if_last_ref));
tmp_h = shard_->Lookup(key3, my_hash);
tmp_h = shard_->Lookup(key3, hkey3);
ASSERT_EQ(h3, tmp_h);
ASSERT_FALSE(shard_->Release(tmp_h, erase_if_last_ref));
}
@ -934,7 +926,7 @@ TEST_F(ClockCacheTest, CollidingInsertEraseTest) {
ASSERT_EQ(deleted, 0);
// Can still find it
tmp_h = shard_->Lookup(key2, my_hash);
tmp_h = shard_->Lookup(key2, hkey2);
ASSERT_EQ(h2, tmp_h);
// Release last ref on h2, with erase
@ -942,12 +934,12 @@ TEST_F(ClockCacheTest, CollidingInsertEraseTest) {
// h2 deleted
ASSERT_EQ(deleted--, 1);
tmp_h = shard_->Lookup(key2, my_hash);
tmp_h = shard_->Lookup(key2, hkey2);
ASSERT_EQ(nullptr, tmp_h);
// Can still find h3
for (bool erase_if_last_ref : {true, false}) { // but not last ref
tmp_h = shard_->Lookup(key3, my_hash);
tmp_h = shard_->Lookup(key3, hkey3);
ASSERT_EQ(h3, tmp_h);
ASSERT_FALSE(shard_->Release(tmp_h, erase_if_last_ref));
}
@ -959,11 +951,11 @@ TEST_F(ClockCacheTest, CollidingInsertEraseTest) {
ASSERT_EQ(deleted, 0);
// Explicit erase
shard_->Erase(key3, my_hash);
shard_->Erase(key3, hkey3);
// h3 deleted
ASSERT_EQ(deleted--, 1);
tmp_h = shard_->Lookup(key3, my_hash);
tmp_h = shard_->Lookup(key3, hkey3);
ASSERT_EQ(nullptr, tmp_h);
}
@ -1371,9 +1363,11 @@ TEST_F(LRUCacheSecondaryCacheTest, SaveFailTest) {
std::string str2 = rnd.RandomString(1020);
TestItem* item2 = new TestItem(str2.data(), str2.length());
// k1 should be demoted to NVM
ASSERT_EQ(secondary_cache->num_inserts(), 0u);
ASSERT_OK(cache->Insert(k2.AsSlice(), item2,
&LRUCacheSecondaryCacheTest::helper_fail_,
str2.length()));
ASSERT_EQ(secondary_cache->num_inserts(), 1u);
Cache::Handle* handle;
handle =

190
cache/sharded_cache.cc vendored
View File

@ -19,184 +19,49 @@
namespace ROCKSDB_NAMESPACE {
namespace {
inline uint32_t HashSlice(const Slice& s) {
return Lower32of64(GetSliceNPHash64(s));
}
} // namespace
ShardedCache::ShardedCache(size_t capacity, int num_shard_bits,
ShardedCacheBase::ShardedCacheBase(size_t capacity, int num_shard_bits,
bool strict_capacity_limit,
std::shared_ptr<MemoryAllocator> allocator)
: Cache(std::move(allocator)),
last_id_(1),
shard_mask_((uint32_t{1} << num_shard_bits) - 1),
capacity_(capacity),
strict_capacity_limit_(strict_capacity_limit),
last_id_(1) {}
capacity_(capacity) {}
void ShardedCache::SetCapacity(size_t capacity) {
size_t ShardedCacheBase::ComputePerShardCapacity(size_t capacity) const {
uint32_t num_shards = GetNumShards();
const size_t per_shard = (capacity + (num_shards - 1)) / num_shards;
MutexLock l(&capacity_mutex_);
for (uint32_t s = 0; s < num_shards; s++) {
GetShard(s)->SetCapacity(per_shard);
}
capacity_ = capacity;
return (capacity + (num_shards - 1)) / num_shards;
}
void ShardedCache::SetStrictCapacityLimit(bool strict_capacity_limit) {
uint32_t num_shards = GetNumShards();
MutexLock l(&capacity_mutex_);
for (uint32_t s = 0; s < num_shards; s++) {
GetShard(s)->SetStrictCapacityLimit(strict_capacity_limit);
}
strict_capacity_limit_ = strict_capacity_limit;
size_t ShardedCacheBase::GetPerShardCapacity() const {
return ComputePerShardCapacity(GetCapacity());
}
Status ShardedCache::Insert(const Slice& key, void* value, size_t charge,
DeleterFn deleter, Handle** handle,
Priority priority) {
uint32_t hash = HashSlice(key);
return GetShard(Shard(hash))
->Insert(key, hash, value, charge, deleter, handle, priority);
}
Status ShardedCache::Insert(const Slice& key, void* value,
const CacheItemHelper* helper, size_t charge,
Handle** handle, Priority priority) {
uint32_t hash = HashSlice(key);
if (!helper) {
return Status::InvalidArgument();
}
return GetShard(Shard(hash))
->Insert(key, hash, value, helper, charge, handle, priority);
}
Cache::Handle* ShardedCache::Lookup(const Slice& key, Statistics* /*stats*/) {
uint32_t hash = HashSlice(key);
return GetShard(Shard(hash))->Lookup(key, hash);
}
Cache::Handle* ShardedCache::Lookup(const Slice& key,
const CacheItemHelper* helper,
const CreateCallback& create_cb,
Priority priority, bool wait,
Statistics* stats) {
uint32_t hash = HashSlice(key);
return GetShard(Shard(hash))
->Lookup(key, hash, helper, create_cb, priority, wait, stats);
}
bool ShardedCache::IsReady(Handle* handle) {
uint32_t hash = GetHash(handle);
return GetShard(Shard(hash))->IsReady(handle);
}
void ShardedCache::Wait(Handle* handle) {
uint32_t hash = GetHash(handle);
GetShard(Shard(hash))->Wait(handle);
}
bool ShardedCache::Ref(Handle* handle) {
uint32_t hash = GetHash(handle);
return GetShard(Shard(hash))->Ref(handle);
}
bool ShardedCache::Release(Handle* handle, bool erase_if_last_ref) {
uint32_t hash = GetHash(handle);
return GetShard(Shard(hash))->Release(handle, erase_if_last_ref);
}
bool ShardedCache::Release(Handle* handle, bool useful,
bool erase_if_last_ref) {
uint32_t hash = GetHash(handle);
return GetShard(Shard(hash))->Release(handle, useful, erase_if_last_ref);
}
void ShardedCache::Erase(const Slice& key) {
uint32_t hash = HashSlice(key);
GetShard(Shard(hash))->Erase(key, hash);
}
uint64_t ShardedCache::NewId() {
uint64_t ShardedCacheBase::NewId() {
return last_id_.fetch_add(1, std::memory_order_relaxed);
}
size_t ShardedCache::GetCapacity() const {
MutexLock l(&capacity_mutex_);
size_t ShardedCacheBase::GetCapacity() const {
MutexLock l(&config_mutex_);
return capacity_;
}
bool ShardedCache::HasStrictCapacityLimit() const {
MutexLock l(&capacity_mutex_);
bool ShardedCacheBase::HasStrictCapacityLimit() const {
MutexLock l(&config_mutex_);
return strict_capacity_limit_;
}
size_t ShardedCache::GetUsage() const {
// We will not lock the cache when getting the usage from shards.
uint32_t num_shards = GetNumShards();
size_t usage = 0;
for (uint32_t s = 0; s < num_shards; s++) {
usage += GetShard(s)->GetUsage();
}
return usage;
}
size_t ShardedCache::GetUsage(Handle* handle) const {
size_t ShardedCacheBase::GetUsage(Handle* handle) const {
return GetCharge(handle);
}
size_t ShardedCache::GetPinnedUsage() const {
// We will not lock the cache when getting the usage from shards.
uint32_t num_shards = GetNumShards();
size_t usage = 0;
for (uint32_t s = 0; s < num_shards; s++) {
usage += GetShard(s)->GetPinnedUsage();
}
return usage;
}
void ShardedCache::ApplyToAllEntries(
const std::function<void(const Slice& key, void* value, size_t charge,
DeleterFn deleter)>& callback,
const ApplyToAllEntriesOptions& opts) {
uint32_t num_shards = GetNumShards();
// Iterate over part of each shard, rotating between shards, to
// minimize impact on latency of concurrent operations.
std::unique_ptr<uint32_t[]> states(new uint32_t[num_shards]{});
uint32_t aepl_in_32 = static_cast<uint32_t>(
std::min(size_t{UINT32_MAX}, opts.average_entries_per_lock));
aepl_in_32 = std::min(aepl_in_32, uint32_t{1});
bool remaining_work;
do {
remaining_work = false;
for (uint32_t s = 0; s < num_shards; s++) {
if (states[s] != UINT32_MAX) {
GetShard(s)->ApplyToSomeEntries(callback, aepl_in_32, &states[s]);
remaining_work |= states[s] != UINT32_MAX;
}
}
} while (remaining_work);
}
void ShardedCache::EraseUnRefEntries() {
uint32_t num_shards = GetNumShards();
for (uint32_t s = 0; s < num_shards; s++) {
GetShard(s)->EraseUnRefEntries();
}
}
std::string ShardedCache::GetPrintableOptions() const {
std::string ShardedCacheBase::GetPrintableOptions() const {
std::string ret;
ret.reserve(20000);
const int kBufferSize = 200;
char buffer[kBufferSize];
{
MutexLock l(&capacity_mutex_);
MutexLock l(&config_mutex_);
snprintf(buffer, kBufferSize, " capacity : %" ROCKSDB_PRIszt "\n",
capacity_);
ret.append(buffer);
@ -210,7 +75,7 @@ std::string ShardedCache::GetPrintableOptions() const {
snprintf(buffer, kBufferSize, " memory_allocator : %s\n",
memory_allocator() ? memory_allocator()->Name() : "None");
ret.append(buffer);
ret.append(GetShard(0)->GetPrintableOptions());
AppendPrintableOptions(ret);
return ret;
}
@ -226,25 +91,10 @@ int GetDefaultCacheShardBits(size_t capacity, size_t min_shard_size) {
return num_shard_bits;
}
int ShardedCache::GetNumShardBits() const { return BitsSetToOne(shard_mask_); }
uint32_t ShardedCache::GetNumShards() const { return shard_mask_ + 1; }
size_t ShardedCache::GetOccupancyCount() const {
size_t oc = 0;
uint32_t num_shards = GetNumShards();
for (uint32_t s = 0; s < num_shards; s++) {
oc += GetShard(s)->GetOccupancyCount();
}
return oc;
}
size_t ShardedCache::GetTableAddressCount() const {
size_t tac = 0;
uint32_t num_shards = GetNumShards();
for (uint32_t s = 0; s < num_shards; s++) {
tac += GetShard(s)->GetTableAddressCount();
}
return tac;
int ShardedCacheBase::GetNumShardBits() const {
return BitsSetToOne(shard_mask_);
}
uint32_t ShardedCacheBase::GetNumShards() const { return shard_mask_ + 1; }
} // namespace ROCKSDB_NAMESPACE

351
cache/sharded_cache.h vendored
View File

@ -10,122 +10,309 @@
#pragma once
#include <atomic>
#include <cstdint>
#include <string>
#include "port/lang.h"
#include "port/port.h"
#include "rocksdb/cache.h"
#include "util/hash.h"
#include "util/mutexlock.h"
namespace ROCKSDB_NAMESPACE {
// Single cache shard interface.
class CacheShard {
// Optional base class for classes implementing the CacheShard concept
class CacheShardBase {
public:
explicit CacheShard(CacheMetadataChargePolicy metadata_charge_policy)
explicit CacheShardBase(CacheMetadataChargePolicy metadata_charge_policy)
: metadata_charge_policy_(metadata_charge_policy) {}
virtual ~CacheShard() = default;
using DeleterFn = Cache::DeleterFn;
virtual Status Insert(const Slice& key, uint32_t hash, void* value,
size_t charge, DeleterFn deleter,
Cache::Handle** handle, Cache::Priority priority) = 0;
virtual Status Insert(const Slice& key, uint32_t hash, void* value,
// Expected by concept CacheShard (TODO with C++20 support)
// Some Defaults
std::string GetPrintableOptions() const { return ""; }
using HashVal = uint64_t;
using HashCref = uint64_t;
static inline HashVal ComputeHash(const Slice& key) {
return GetSliceNPHash64(key);
}
static inline uint32_t HashPieceForSharding(HashCref hash) {
return Lower32of64(hash);
}
void AppendPrintableOptions(std::string& /*str*/) const {}
// Must be provided for concept CacheShard (TODO with C++20 support)
/*
struct HandleImpl { // for concept HandleImpl
HashVal hash;
HashCref GetHash() const;
...
};
Status Insert(const Slice& key, HashCref hash, void* value, size_t charge,
DeleterFn deleter, HandleImpl** handle,
Cache::Priority priority) = 0;
Status Insert(const Slice& key, HashCref hash, void* value,
const Cache::CacheItemHelper* helper, size_t charge,
Cache::Handle** handle, Cache::Priority priority) = 0;
virtual Cache::Handle* Lookup(const Slice& key, uint32_t hash) = 0;
virtual Cache::Handle* Lookup(const Slice& key, uint32_t hash,
HandleImpl** handle, Cache::Priority priority) = 0;
HandleImpl* Lookup(const Slice& key, HashCref hash) = 0;
HandleImpl* Lookup(const Slice& key, HashCref hash,
const Cache::CacheItemHelper* helper,
const Cache::CreateCallback& create_cb,
Cache::Priority priority, bool wait,
Statistics* stats) = 0;
virtual bool Release(Cache::Handle* handle, bool useful,
bool erase_if_last_ref) = 0;
virtual bool IsReady(Cache::Handle* handle) = 0;
virtual void Wait(Cache::Handle* handle) = 0;
virtual bool Ref(Cache::Handle* handle) = 0;
virtual bool Release(Cache::Handle* handle, bool erase_if_last_ref) = 0;
virtual void Erase(const Slice& key, uint32_t hash) = 0;
virtual void SetCapacity(size_t capacity) = 0;
virtual void SetStrictCapacityLimit(bool strict_capacity_limit) = 0;
virtual size_t GetUsage() const = 0;
virtual size_t GetPinnedUsage() const = 0;
virtual size_t GetOccupancyCount() const = 0;
virtual size_t GetTableAddressCount() const = 0;
bool Release(HandleImpl* handle, bool useful, bool erase_if_last_ref) = 0;
bool IsReady(HandleImpl* handle) = 0;
void Wait(HandleImpl* handle) = 0;
bool Ref(HandleImpl* handle) = 0;
void Erase(const Slice& key, HashCref hash) = 0;
void SetCapacity(size_t capacity) = 0;
void SetStrictCapacityLimit(bool strict_capacity_limit) = 0;
size_t GetUsage() const = 0;
size_t GetPinnedUsage() const = 0;
size_t GetOccupancyCount() const = 0;
size_t GetTableAddressCount() const = 0;
// Handles iterating over roughly `average_entries_per_lock` entries, using
// `state` to somehow record where it last ended up. Caller initially uses
// *state == 0 and implementation sets *state = UINT32_MAX to indicate
// *state == 0 and implementation sets *state = SIZE_MAX to indicate
// completion.
virtual void ApplyToSomeEntries(
void ApplyToSomeEntries(
const std::function<void(const Slice& key, void* value, size_t charge,
DeleterFn deleter)>& callback,
uint32_t average_entries_per_lock, uint32_t* state) = 0;
virtual void EraseUnRefEntries() = 0;
virtual std::string GetPrintableOptions() const { return ""; }
size_t average_entries_per_lock, size_t* state) = 0;
void EraseUnRefEntries() = 0;
*/
protected:
const CacheMetadataChargePolicy metadata_charge_policy_;
};
// Generic cache interface which shards cache by hash of keys. 2^num_shard_bits
// shards will be created, with capacity split evenly to each of the shards.
// Keys are sharded by the highest num_shard_bits bits of hash value.
class ShardedCache : public Cache {
// Portions of ShardedCache that do not depend on the template parameter
class ShardedCacheBase : public Cache {
public:
ShardedCache(size_t capacity, int num_shard_bits, bool strict_capacity_limit,
std::shared_ptr<MemoryAllocator> memory_allocator = nullptr);
virtual ~ShardedCache() = default;
virtual CacheShard* GetShard(uint32_t shard) = 0;
virtual const CacheShard* GetShard(uint32_t shard) const = 0;
virtual uint32_t GetHash(Handle* handle) const = 0;
virtual void SetCapacity(size_t capacity) override;
virtual void SetStrictCapacityLimit(bool strict_capacity_limit) override;
virtual Status Insert(const Slice& key, void* value, size_t charge,
DeleterFn deleter, Handle** handle,
Priority priority) override;
virtual Status Insert(const Slice& key, void* value,
const CacheItemHelper* helper, size_t charge,
Handle** handle = nullptr,
Priority priority = Priority::LOW) override;
virtual Handle* Lookup(const Slice& key, Statistics* stats) override;
virtual Handle* Lookup(const Slice& key, const CacheItemHelper* helper,
const CreateCallback& create_cb, Priority priority,
bool wait, Statistics* stats = nullptr) override;
virtual bool Release(Handle* handle, bool useful,
bool erase_if_last_ref = false) override;
virtual bool IsReady(Handle* handle) override;
virtual void Wait(Handle* handle) override;
virtual bool Ref(Handle* handle) override;
virtual bool Release(Handle* handle, bool erase_if_last_ref = false) override;
virtual void Erase(const Slice& key) override;
virtual uint64_t NewId() override;
virtual size_t GetCapacity() const override;
virtual bool HasStrictCapacityLimit() const override;
virtual size_t GetUsage() const override;
virtual size_t GetUsage(Handle* handle) const override;
virtual size_t GetPinnedUsage() const override;
virtual size_t GetOccupancyCount() const override;
virtual size_t GetTableAddressCount() const override;
virtual void ApplyToAllEntries(
const std::function<void(const Slice& key, void* value, size_t charge,
DeleterFn deleter)>& callback,
const ApplyToAllEntriesOptions& opts) override;
virtual void EraseUnRefEntries() override;
virtual std::string GetPrintableOptions() const override;
ShardedCacheBase(size_t capacity, int num_shard_bits,
bool strict_capacity_limit,
std::shared_ptr<MemoryAllocator> memory_allocator);
virtual ~ShardedCacheBase() = default;
int GetNumShardBits() const;
uint32_t GetNumShards() const;
uint64_t NewId() override;
bool HasStrictCapacityLimit() const override;
size_t GetCapacity() const override;
using Cache::GetUsage;
size_t GetUsage(Handle* handle) const override;
std::string GetPrintableOptions() const override;
protected: // fns
virtual void AppendPrintableOptions(std::string& str) const = 0;
size_t GetPerShardCapacity() const;
size_t ComputePerShardCapacity(size_t capacity) const;
protected: // data
std::atomic<uint64_t> last_id_; // For NewId
const uint32_t shard_mask_;
// Dynamic configuration parameters, guarded by config_mutex_
bool strict_capacity_limit_;
size_t capacity_;
mutable port::Mutex config_mutex_;
};
// Generic cache interface that shards cache by hash of keys. 2^num_shard_bits
// shards will be created, with capacity split evenly to each of the shards.
// Keys are typically sharded by the lowest num_shard_bits bits of hash value
// so that the upper bits of the hash value can keep a stable ordering of
// table entries even as the table grows (using more upper hash bits).
// See CacheShardBase above for what is expected of the CacheShard parameter.
template <class CacheShard>
class ShardedCache : public ShardedCacheBase {
public:
using HashVal = typename CacheShard::HashVal;
using HashCref = typename CacheShard::HashCref;
using HandleImpl = typename CacheShard::HandleImpl;
ShardedCache(size_t capacity, int num_shard_bits, bool strict_capacity_limit,
std::shared_ptr<MemoryAllocator> allocator)
: ShardedCacheBase(capacity, num_shard_bits, strict_capacity_limit,
allocator),
shards_(reinterpret_cast<CacheShard*>(port::cacheline_aligned_alloc(
sizeof(CacheShard) * GetNumShards()))),
destroy_shards_in_dtor_(false) {}
virtual ~ShardedCache() {
if (destroy_shards_in_dtor_) {
ForEachShard([](CacheShard* cs) { cs->~CacheShard(); });
}
port::cacheline_aligned_free(shards_);
}
CacheShard& GetShard(HashCref hash) {
return shards_[CacheShard::HashPieceForSharding(hash) & shard_mask_];
}
const CacheShard& GetShard(HashCref hash) const {
return shards_[CacheShard::HashPieceForSharding(hash) & shard_mask_];
}
void SetCapacity(size_t capacity) override {
MutexLock l(&config_mutex_);
capacity_ = capacity;
auto per_shard = ComputePerShardCapacity(capacity);
ForEachShard([=](CacheShard* cs) { cs->SetCapacity(per_shard); });
}
void SetStrictCapacityLimit(bool s_c_l) override {
MutexLock l(&config_mutex_);
strict_capacity_limit_ = s_c_l;
ForEachShard(
[s_c_l](CacheShard* cs) { cs->SetStrictCapacityLimit(s_c_l); });
}
Status Insert(const Slice& key, void* value, size_t charge, DeleterFn deleter,
Handle** handle, Priority priority) override {
HashVal hash = CacheShard::ComputeHash(key);
auto h_out = reinterpret_cast<HandleImpl**>(handle);
return GetShard(hash).Insert(key, hash, value, charge, deleter, h_out,
priority);
}
Status Insert(const Slice& key, void* value, const CacheItemHelper* helper,
size_t charge, Handle** handle = nullptr,
Priority priority = Priority::LOW) override {
if (!helper) {
return Status::InvalidArgument();
}
HashVal hash = CacheShard::ComputeHash(key);
auto h_out = reinterpret_cast<HandleImpl**>(handle);
return GetShard(hash).Insert(key, hash, value, helper, charge, h_out,
priority);
}
Handle* Lookup(const Slice& key, Statistics* /*stats*/) override {
HashVal hash = CacheShard::ComputeHash(key);
HandleImpl* result = GetShard(hash).Lookup(key, hash);
return reinterpret_cast<Handle*>(result);
}
Handle* Lookup(const Slice& key, const CacheItemHelper* helper,
const CreateCallback& create_cb, Priority priority, bool wait,
Statistics* stats = nullptr) override {
HashVal hash = CacheShard::ComputeHash(key);
HandleImpl* result = GetShard(hash).Lookup(key, hash, helper, create_cb,
priority, wait, stats);
return reinterpret_cast<Handle*>(result);
}
void Erase(const Slice& key) override {
HashVal hash = CacheShard::ComputeHash(key);
GetShard(hash).Erase(key, hash);
}
bool Release(Handle* handle, bool useful,
bool erase_if_last_ref = false) override {
auto h = reinterpret_cast<HandleImpl*>(handle);
return GetShard(h->GetHash()).Release(h, useful, erase_if_last_ref);
}
bool IsReady(Handle* handle) override {
auto h = reinterpret_cast<HandleImpl*>(handle);
return GetShard(h->GetHash()).IsReady(h);
}
void Wait(Handle* handle) override {
auto h = reinterpret_cast<HandleImpl*>(handle);
GetShard(h->GetHash()).Wait(h);
}
bool Ref(Handle* handle) override {
auto h = reinterpret_cast<HandleImpl*>(handle);
return GetShard(h->GetHash()).Ref(h);
}
bool Release(Handle* handle, bool erase_if_last_ref = false) override {
return Release(handle, true /*useful*/, erase_if_last_ref);
}
using ShardedCacheBase::GetUsage;
size_t GetUsage() const override {
return SumOverShards2(&CacheShard::GetUsage);
}
size_t GetPinnedUsage() const override {
return SumOverShards2(&CacheShard::GetPinnedUsage);
}
size_t GetOccupancyCount() const override {
return SumOverShards2(&CacheShard::GetPinnedUsage);
}
size_t GetTableAddressCount() const override {
return SumOverShards2(&CacheShard::GetTableAddressCount);
}
void ApplyToAllEntries(
const std::function<void(const Slice& key, void* value, size_t charge,
DeleterFn deleter)>& callback,
const ApplyToAllEntriesOptions& opts) override {
uint32_t num_shards = GetNumShards();
// Iterate over part of each shard, rotating between shards, to
// minimize impact on latency of concurrent operations.
std::unique_ptr<size_t[]> states(new size_t[num_shards]{});
size_t aepl = opts.average_entries_per_lock;
aepl = std::min(aepl, size_t{1});
bool remaining_work;
do {
remaining_work = false;
for (uint32_t i = 0; i < num_shards; i++) {
if (states[i] != SIZE_MAX) {
shards_[i].ApplyToSomeEntries(callback, aepl, &states[i]);
remaining_work |= states[i] != SIZE_MAX;
}
}
} while (remaining_work);
}
virtual void EraseUnRefEntries() override {
ForEachShard([](CacheShard* cs) { cs->EraseUnRefEntries(); });
}
void DisownData() override {
// Leak data only if that won't generate an ASAN/valgrind warning.
if (!kMustFreeHeapAllocations) {
destroy_shards_in_dtor_ = false;
}
}
protected:
inline uint32_t Shard(uint32_t hash) { return hash & shard_mask_; }
inline void ForEachShard(const std::function<void(CacheShard*)>& fn) {
uint32_t num_shards = GetNumShards();
for (uint32_t i = 0; i < num_shards; i++) {
fn(shards_ + i);
}
}
inline size_t SumOverShards(
const std::function<size_t(CacheShard&)>& fn) const {
uint32_t num_shards = GetNumShards();
size_t result = 0;
for (uint32_t i = 0; i < num_shards; i++) {
result += fn(shards_[i]);
}
return result;
}
inline size_t SumOverShards2(size_t (CacheShard::*fn)() const) const {
return SumOverShards([fn](CacheShard& cs) { return (cs.*fn)(); });
}
// Must be called exactly once by derived class constructor
void InitShards(const std::function<void(CacheShard*)>& placement_new) {
ForEachShard(placement_new);
destroy_shards_in_dtor_ = true;
}
void AppendPrintableOptions(std::string& str) const override {
shards_[0].AppendPrintableOptions(str);
}
private:
const uint32_t shard_mask_;
mutable port::Mutex capacity_mutex_;
size_t capacity_;
bool strict_capacity_limit_;
std::atomic<uint64_t> last_id_;
CacheShard* const shards_;
bool destroy_shards_in_dtor_;
};
// 512KB is traditional minimum shard size.

96
options/options_test.cc
View File

@ -613,7 +613,7 @@ TEST_F(OptionsTest, GetColumnFamilyOptionsFromStringTest) {
&new_cf_opt));
ASSERT_NE(new_cf_opt.blob_cache, nullptr);
ASSERT_EQ(new_cf_opt.blob_cache->GetCapacity(), 1024UL * 1024UL);
ASSERT_EQ(static_cast<ShardedCache*>(new_cf_opt.blob_cache.get())
ASSERT_EQ(static_cast<ShardedCacheBase*>(new_cf_opt.blob_cache.get())
->GetNumShardBits(),
4);
ASSERT_EQ(new_cf_opt.blob_cache->HasStrictCapacityLimit(), true);
@ -1064,15 +1064,18 @@ TEST_F(OptionsTest, GetBlockBasedTableOptionsFromString) {
&new_opt));
ASSERT_TRUE(new_opt.block_cache != nullptr);
ASSERT_EQ(new_opt.block_cache->GetCapacity(), 1024UL*1024UL);
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCache>(
new_opt.block_cache)->GetNumShardBits(), 4);
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCacheBase>(new_opt.block_cache)
->GetNumShardBits(),
4);
ASSERT_EQ(new_opt.block_cache->HasStrictCapacityLimit(), true);
ASSERT_EQ(std::dynamic_pointer_cast<LRUCache>(
new_opt.block_cache)->GetHighPriPoolRatio(), 0.5);
ASSERT_TRUE(new_opt.block_cache_compressed != nullptr);
ASSERT_EQ(new_opt.block_cache_compressed->GetCapacity(), 1024UL*1024UL);
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCache>(
new_opt.block_cache_compressed)->GetNumShardBits(), 4);
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCacheBase>(
new_opt.block_cache_compressed)
->GetNumShardBits(),
4);
ASSERT_EQ(new_opt.block_cache_compressed->HasStrictCapacityLimit(), true);
ASSERT_EQ(std::dynamic_pointer_cast<LRUCache>(
new_opt.block_cache_compressed)->GetHighPriPoolRatio(),
@ -1088,8 +1091,8 @@ TEST_F(OptionsTest, GetBlockBasedTableOptionsFromString) {
ASSERT_TRUE(new_opt.block_cache != nullptr);
ASSERT_EQ(new_opt.block_cache->GetCapacity(), 2*1024UL*1024UL);
// Default values
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCache>(
new_opt.block_cache)->GetNumShardBits(),
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCacheBase>(new_opt.block_cache)
->GetNumShardBits(),
GetDefaultCacheShardBits(new_opt.block_cache->GetCapacity()));
ASSERT_EQ(new_opt.block_cache->HasStrictCapacityLimit(), false);
ASSERT_EQ(std::dynamic_pointer_cast<LRUCache>(new_opt.block_cache)
@ -1098,10 +1101,11 @@ TEST_F(OptionsTest, GetBlockBasedTableOptionsFromString) {
ASSERT_TRUE(new_opt.block_cache_compressed != nullptr);
ASSERT_EQ(new_opt.block_cache_compressed->GetCapacity(), 2*1024UL*1024UL);
// Default values
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCache>(
new_opt.block_cache_compressed)->GetNumShardBits(),
GetDefaultCacheShardBits(
new_opt.block_cache_compressed->GetCapacity()));
ASSERT_EQ(
std::dynamic_pointer_cast<ShardedCacheBase>(
new_opt.block_cache_compressed)
->GetNumShardBits(),
GetDefaultCacheShardBits(new_opt.block_cache_compressed->GetCapacity()));
ASSERT_EQ(new_opt.block_cache_compressed->HasStrictCapacityLimit(), false);
ASSERT_EQ(std::dynamic_pointer_cast<LRUCache>(new_opt.block_cache_compressed)
->GetHighPriPoolRatio(),
@ -1115,15 +1119,18 @@ TEST_F(OptionsTest, GetBlockBasedTableOptionsFromString) {
"high_pri_pool_ratio=0.0;}",
&new_opt));
ASSERT_EQ(new_opt.block_cache->GetCapacity(), 0);
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCache>(
new_opt.block_cache)->GetNumShardBits(), 5);
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCacheBase>(new_opt.block_cache)
->GetNumShardBits(),
5);
ASSERT_EQ(new_opt.block_cache->HasStrictCapacityLimit(), false);
ASSERT_EQ(std::dynamic_pointer_cast<LRUCache>(
new_opt.block_cache)->GetHighPriPoolRatio(), 0.5);
ASSERT_TRUE(new_opt.block_cache_compressed != nullptr);
ASSERT_EQ(new_opt.block_cache_compressed->GetCapacity(), 0);
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCache>(
new_opt.block_cache_compressed)->GetNumShardBits(), 5);
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCacheBase>(
new_opt.block_cache_compressed)
->GetNumShardBits(),
5);
ASSERT_EQ(new_opt.block_cache_compressed->HasStrictCapacityLimit(), false);
ASSERT_EQ(std::dynamic_pointer_cast<LRUCache>(new_opt.block_cache_compressed)
->GetHighPriPoolRatio(),
@ -1139,16 +1146,19 @@ TEST_F(OptionsTest, GetBlockBasedTableOptionsFromString) {
&new_opt));
ASSERT_TRUE(new_opt.block_cache != nullptr);
ASSERT_EQ(new_opt.block_cache->GetCapacity(), 1024UL*1024UL);
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCache>(
new_opt.block_cache)->GetNumShardBits(), 4);
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCacheBase>(new_opt.block_cache)
->GetNumShardBits(),
4);
ASSERT_EQ(new_opt.block_cache->HasStrictCapacityLimit(), true);
ASSERT_EQ(std::dynamic_pointer_cast<LRUCache>(new_opt.block_cache)
->GetHighPriPoolRatio(),
0.5);
ASSERT_TRUE(new_opt.block_cache_compressed != nullptr);
ASSERT_EQ(new_opt.block_cache_compressed->GetCapacity(), 1024UL*1024UL);
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCache>(
new_opt.block_cache_compressed)->GetNumShardBits(), 4);
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCacheBase>(
new_opt.block_cache_compressed)
->GetNumShardBits(),
4);
ASSERT_EQ(new_opt.block_cache_compressed->HasStrictCapacityLimit(), true);
ASSERT_EQ(std::dynamic_pointer_cast<LRUCache>(new_opt.block_cache_compressed)
->GetHighPriPoolRatio(),
@ -2790,7 +2800,7 @@ TEST_F(OptionsOldApiTest, GetColumnFamilyOptionsFromStringTest) {
&new_cf_opt));
ASSERT_NE(new_cf_opt.blob_cache, nullptr);
ASSERT_EQ(new_cf_opt.blob_cache->GetCapacity(), 1024UL * 1024UL);
ASSERT_EQ(static_cast<ShardedCache*>(new_cf_opt.blob_cache.get())
ASSERT_EQ(static_cast<ShardedCacheBase*>(new_cf_opt.blob_cache.get())
->GetNumShardBits(),
4);
ASSERT_EQ(new_cf_opt.blob_cache->HasStrictCapacityLimit(), true);
@ -2970,15 +2980,18 @@ TEST_F(OptionsOldApiTest, GetBlockBasedTableOptionsFromString) {
&new_opt));
ASSERT_TRUE(new_opt.block_cache != nullptr);
ASSERT_EQ(new_opt.block_cache->GetCapacity(), 1024UL*1024UL);
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCache>(
new_opt.block_cache)->GetNumShardBits(), 4);
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCacheBase>(new_opt.block_cache)
->GetNumShardBits(),
4);
ASSERT_EQ(new_opt.block_cache->HasStrictCapacityLimit(), true);
ASSERT_EQ(std::dynamic_pointer_cast<LRUCache>(
new_opt.block_cache)->GetHighPriPoolRatio(), 0.5);
ASSERT_TRUE(new_opt.block_cache_compressed != nullptr);
ASSERT_EQ(new_opt.block_cache_compressed->GetCapacity(), 1024UL*1024UL);
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCache>(
new_opt.block_cache_compressed)->GetNumShardBits(), 4);
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCacheBase>(
new_opt.block_cache_compressed)
->GetNumShardBits(),
4);
ASSERT_EQ(new_opt.block_cache_compressed->HasStrictCapacityLimit(), true);
ASSERT_EQ(std::dynamic_pointer_cast<LRUCache>(
new_opt.block_cache_compressed)->GetHighPriPoolRatio(),
@ -2993,8 +3006,8 @@ TEST_F(OptionsOldApiTest, GetBlockBasedTableOptionsFromString) {
ASSERT_TRUE(new_opt.block_cache != nullptr);
ASSERT_EQ(new_opt.block_cache->GetCapacity(), 2*1024UL*1024UL);
// Default values
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCache>(
new_opt.block_cache)->GetNumShardBits(),
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCacheBase>(new_opt.block_cache)
->GetNumShardBits(),
GetDefaultCacheShardBits(new_opt.block_cache->GetCapacity()));
ASSERT_EQ(new_opt.block_cache->HasStrictCapacityLimit(), false);
ASSERT_EQ(std::dynamic_pointer_cast<LRUCache>(new_opt.block_cache)
@ -3003,10 +3016,11 @@ TEST_F(OptionsOldApiTest, GetBlockBasedTableOptionsFromString) {
ASSERT_TRUE(new_opt.block_cache_compressed != nullptr);
ASSERT_EQ(new_opt.block_cache_compressed->GetCapacity(), 2*1024UL*1024UL);
// Default values
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCache>(
new_opt.block_cache_compressed)->GetNumShardBits(),
GetDefaultCacheShardBits(
new_opt.block_cache_compressed->GetCapacity()));
ASSERT_EQ(
std::dynamic_pointer_cast<ShardedCacheBase>(
new_opt.block_cache_compressed)
->GetNumShardBits(),
GetDefaultCacheShardBits(new_opt.block_cache_compressed->GetCapacity()));
ASSERT_EQ(new_opt.block_cache_compressed->HasStrictCapacityLimit(), false);
ASSERT_EQ(std::dynamic_pointer_cast<LRUCache>(new_opt.block_cache_compressed)
->GetHighPriPoolRatio(),
@ -3020,15 +3034,18 @@ TEST_F(OptionsOldApiTest, GetBlockBasedTableOptionsFromString) {
"high_pri_pool_ratio=0.0;}",
&new_opt));
ASSERT_EQ(new_opt.block_cache->GetCapacity(), 0);
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCache>(
new_opt.block_cache)->GetNumShardBits(), 5);
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCacheBase>(new_opt.block_cache)
->GetNumShardBits(),
5);
ASSERT_EQ(new_opt.block_cache->HasStrictCapacityLimit(), false);
ASSERT_EQ(std::dynamic_pointer_cast<LRUCache>(
new_opt.block_cache)->GetHighPriPoolRatio(), 0.5);
ASSERT_TRUE(new_opt.block_cache_compressed != nullptr);
ASSERT_EQ(new_opt.block_cache_compressed->GetCapacity(), 0);
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCache>(
new_opt.block_cache_compressed)->GetNumShardBits(), 5);
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCacheBase>(
new_opt.block_cache_compressed)
->GetNumShardBits(),
5);
ASSERT_EQ(new_opt.block_cache_compressed->HasStrictCapacityLimit(), false);
ASSERT_EQ(std::dynamic_pointer_cast<LRUCache>(new_opt.block_cache_compressed)
->GetHighPriPoolRatio(),
@ -3043,16 +3060,19 @@ TEST_F(OptionsOldApiTest, GetBlockBasedTableOptionsFromString) {
&new_opt));
ASSERT_TRUE(new_opt.block_cache != nullptr);
ASSERT_EQ(new_opt.block_cache->GetCapacity(), 1024UL*1024UL);
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCache>(
new_opt.block_cache)->GetNumShardBits(), 4);
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCacheBase>(new_opt.block_cache)
->GetNumShardBits(),
4);
ASSERT_EQ(new_opt.block_cache->HasStrictCapacityLimit(), true);
ASSERT_EQ(std::dynamic_pointer_cast<LRUCache>(new_opt.block_cache)
->GetHighPriPoolRatio(),
0.5);
ASSERT_TRUE(new_opt.block_cache_compressed != nullptr);
ASSERT_EQ(new_opt.block_cache_compressed->GetCapacity(), 1024UL*1024UL);
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCache>(
new_opt.block_cache_compressed)->GetNumShardBits(), 4);
ASSERT_EQ(std::dynamic_pointer_cast<ShardedCacheBase>(
new_opt.block_cache_compressed)
->GetNumShardBits(),
4);
ASSERT_EQ(new_opt.block_cache_compressed->HasStrictCapacityLimit(), true);
ASSERT_EQ(std::dynamic_pointer_cast<LRUCache>(new_opt.block_cache_compressed)
->GetHighPriPoolRatio(),

9
port/win/port_win.h
View File

@ -246,13 +246,8 @@ inline void cacheline_aligned_free(void *memblock) {
extern const size_t kPageSize;
// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52991 for MINGW32
// could not be worked around with by -mno-ms-bitfields
#ifndef __MINGW32__
#define ALIGN_AS(n) __declspec(align(n))
#else
#define ALIGN_AS(n)
#endif
// Part of C++11
#define ALIGN_AS(n) alignas(n)
static inline void AsmVolatilePause() {
#if defined(_M_IX86) || defined(_M_X64) || defined(_M_ARM64) || defined(_M_ARM)

14
table/block_based/block_based_table_factory.cc
View File

@ -524,32 +524,32 @@ Status CheckCacheOptionCompatibility(const BlockBasedTableOptions& bbto) {
// More complex test of shared key space, in case the instances are wrappers
// for some shared underlying cache.
std::string sentinel_key(size_t{1}, '\0');
CacheKey sentinel_key = CacheKey::CreateUniqueForProcessLifetime();
static char kRegularBlockCacheMarker = 'b';
static char kCompressedBlockCacheMarker = 'c';
static char kPersistentCacheMarker = 'p';
if (bbto.block_cache) {
bbto.block_cache
->Insert(Slice(sentinel_key), &kRegularBlockCacheMarker, 1,
->Insert(sentinel_key.AsSlice(), &kRegularBlockCacheMarker, 1,
GetNoopDeleterForRole<CacheEntryRole::kMisc>())
.PermitUncheckedError();
}
if (bbto.block_cache_compressed) {
bbto.block_cache_compressed
->Insert(Slice(sentinel_key), &kCompressedBlockCacheMarker, 1,
->Insert(sentinel_key.AsSlice(), &kCompressedBlockCacheMarker, 1,
GetNoopDeleterForRole<CacheEntryRole::kMisc>())
.PermitUncheckedError();
}
if (bbto.persistent_cache) {
// Note: persistent cache copies the data, not keeping the pointer
bbto.persistent_cache
->Insert(Slice(sentinel_key), &kPersistentCacheMarker, 1)
->Insert(sentinel_key.AsSlice(), &kPersistentCacheMarker, 1)
.PermitUncheckedError();
}
// If we get something different from what we inserted, that indicates
// dangerously overlapping key spaces.
if (bbto.block_cache) {
auto handle = bbto.block_cache->Lookup(Slice(sentinel_key));
auto handle = bbto.block_cache->Lookup(sentinel_key.AsSlice());
if (handle) {
auto v = static_cast<char*>(bbto.block_cache->Value(handle));
char c = *v;
@ -568,7 +568,7 @@ Status CheckCacheOptionCompatibility(const BlockBasedTableOptions& bbto) {
}
}
if (bbto.block_cache_compressed) {
auto handle = bbto.block_cache_compressed->Lookup(Slice(sentinel_key));
auto handle = bbto.block_cache_compressed->Lookup(sentinel_key.AsSlice());
if (handle) {
auto v = static_cast<char*>(bbto.block_cache_compressed->Value(handle));
char c = *v;
@ -591,7 +591,7 @@ Status CheckCacheOptionCompatibility(const BlockBasedTableOptions& bbto) {
if (bbto.persistent_cache) {
std::unique_ptr<char[]> data;
size_t size = 0;
bbto.persistent_cache->Lookup(Slice(sentinel_key), &data, &size)
bbto.persistent_cache->Lookup(sentinel_key.AsSlice(), &data, &size)
.PermitUncheckedError();
if (data && size > 0) {
if (data[0] == kRegularBlockCacheMarker) {

1
table/block_based/block_based_table_reader.cc
View File

@ -21,7 +21,6 @@
#include "cache/cache_entry_roles.h"
#include "cache/cache_key.h"
#include "cache/sharded_cache.h"
#include "db/compaction/compaction_picker.h"
#include "db/dbformat.h"
#include "db/pinned_iterators_manager.h"