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4 commits

Author SHA1 Message Date
haoyuhuang 2e8ad03ab3 Add more stats in the block cache trace analyzer (#5482)
Summary:
This PR adds more stats in the block cache trace analyzer.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5482

Differential Revision: D15883553

Pulled By: HaoyuHuang

fbshipit-source-id: 6d440e4f657af75690420102d532d0ee1ed4e9cf
2019-06-18 18:38:42 -07:00
haoyuhuang bcfc53b436 Block cache tracing: Fix minor bugs with downsampling and some benchmark results. (#5473)
Summary:
As the code changes for block cache tracing are almost complete, I did a benchmark to compare the performance when block cache tracing is enabled/disabled.

 With 1% downsampling ratio, the performance overhead of block cache tracing is negligible. When we trace all block accesses, the throughput drops by 6 folds with 16 threads issuing random reads and all reads are served in block cache.

Setup:
RocksDB:    version 6.2
Date:       Mon Jun 17 17:11:13 2019
CPU:        24 * Intel Core Processor (Skylake)
CPUCache:   16384 KB
Keys:       20 bytes each
Values:     100 bytes each (100 bytes after compression)
Entries:    10000000
Prefix:    20 bytes
Keys per prefix:    0
RawSize:    1144.4 MB (estimated)
FileSize:   1144.4 MB (estimated)
Write rate: 0 bytes/second
Read rate: 0 ops/second
Compression: NoCompression
Compression sampling rate: 0
Memtablerep: skip_list
Perf Level: 1

I ran the readrandom workload for 1 minute. Detailed throughput results:  (ops/second)
Sample rate 0: no block cache tracing.
Sample rate 1: trace all block accesses.
Sample rate 100: trace accesses 1% blocks.
1 thread |   |   |  -- | -- | -- | --
Sample rate | 0 | 1 | 100
1 MB block cache size | 13,094 | 13,166 | 13,341
10 GB block cache size | 202,243 | 188,677 | 229,182

16 threads |   |   |  -- | -- | -- | --
Sample rate | 0 | 1 | 100
1 MB block cache size | 208,761 | 178,700 | 201,872
10 GB block cache size | 2,645,996 | 426,295 | 2,587,605
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5473

Differential Revision: D15869479

Pulled By: HaoyuHuang

fbshipit-source-id: 7ae802abe84811281a6af8649f489887cd7c4618
2019-06-17 17:59:02 -07:00
haoyuhuang 2d1dd5bce7 Support computing miss ratio curves using sim_cache. (#5449)
Summary:
This PR adds a BlockCacheTraceSimulator that reports the miss ratios given different cache configurations. A cache configuration contains "cache_name,num_shard_bits,cache_capacities". For example, "lru, 1, 1K, 2K, 4M, 4G".

When we replay the trace, we also perform lookups and inserts on the simulated caches.
In the end, it reports the miss ratio for each tuple <cache_name, num_shard_bits, cache_capacity> in a output file.

This PR also adds a main source block_cache_trace_analyzer so that we can run the analyzer in command line.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5449

Test Plan:
Added tests for block_cache_trace_analyzer.
COMPILE_WITH_ASAN=1 make check -j32.

Differential Revision: D15797073

Pulled By: HaoyuHuang

fbshipit-source-id: aef0c5c2e7938f3e8b6a10d4a6a50e6928ecf408
2019-06-17 16:41:12 -07:00
haoyuhuang 9bbccda01e First commit for block cache trace analyzer (#5425)
Summary:
This PR contains the first commit for block cache trace analyzer. It reads a block cache trace file and prints statistics of the traces.

We will extend this class to provide more functionalities.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5425

Differential Revision: D15709580

Pulled By: HaoyuHuang

fbshipit-source-id: 2f43bd2311f460ab569880819d95eeae217c20bb
2019-06-11 12:22:44 -07:00