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https://github.com/facebook/rocksdb.git
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5ef1ba7ff5
Summary: A generic rate limiter that can be shared by threads and rocksdb instances. Will use this to smooth out write traffic generated by compaction and flush. This will help us get better p99 behavior on flash storage. Test Plan: unit test output ==== Test RateLimiterTest.Rate request size [1 - 1023], limit 10 KB/sec, actual rate: 10.374969 KB/sec, elapsed 2002265 request size [1 - 2047], limit 20 KB/sec, actual rate: 20.771242 KB/sec, elapsed 2002139 request size [1 - 4095], limit 40 KB/sec, actual rate: 41.285299 KB/sec, elapsed 2202424 request size [1 - 8191], limit 80 KB/sec, actual rate: 81.371605 KB/sec, elapsed 2402558 request size [1 - 16383], limit 160 KB/sec, actual rate: 162.541268 KB/sec, elapsed 3303500 Reviewers: yhchiang, igor, sdong Reviewed By: sdong Subscribers: leveldb Differential Revision: https://reviews.facebook.net/D19359
89 lines
2.3 KiB
C++
89 lines
2.3 KiB
C++
// Copyright (c) 2014, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#pragma once
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#include <thread>
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#include <deque>
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#include "port/port_posix.h"
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#include "util/mutexlock.h"
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#include "util/random.h"
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#include "rocksdb/env.h"
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namespace rocksdb {
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class RateLimiter {
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public:
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RateLimiter(int64_t refill_bytes, int64_t refill_period_us, int32_t fairness);
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~RateLimiter();
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// Request for token to write bytes. If this request can not be satisfied,
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// the call is blocked. Caller is responsible to make sure
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// bytes < GetSingleBurstBytes()
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void Request(const int64_t bytes, const Env::IOPriority pri);
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int64_t GetTotalBytesThrough(
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const Env::IOPriority pri = Env::IO_TOTAL) const {
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MutexLock g(&request_mutex_);
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if (pri == Env::IO_TOTAL) {
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return total_bytes_through_[Env::IO_LOW] +
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total_bytes_through_[Env::IO_HIGH];
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}
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return total_bytes_through_[pri];
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}
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int64_t GetTotalRequests(const Env::IOPriority pri = Env::IO_TOTAL) const {
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MutexLock g(&request_mutex_);
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if (pri == Env::IO_TOTAL) {
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return total_requests_[Env::IO_LOW] + total_requests_[Env::IO_HIGH];
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}
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return total_requests_[pri];
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}
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int64_t GetSingleBurstBytes() const {
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// const var
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return refill_bytes_per_period_;
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}
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int64_t GetAvailableBytes() const {
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MutexLock g(&request_mutex_);
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return available_bytes_;
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}
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private:
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void Refill();
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// This mutex guard all internal states
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mutable port::Mutex request_mutex_;
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const int64_t refill_period_us_;
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const int64_t refill_bytes_per_period_;
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Env* const env_;
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bool stop_;
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port::CondVar exit_cv_;
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int32_t requests_to_wait_;
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int64_t total_requests_[Env::IO_TOTAL];
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int64_t total_bytes_through_[Env::IO_TOTAL];
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int64_t available_bytes_;
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int64_t next_refill_us_;
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int32_t fairness_;
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Random rnd_;
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struct Req;
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Req* leader_;
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std::deque<Req*> queue_[Env::IO_TOTAL];
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};
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} // namespace rocksdb
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