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| author | Xin Tong <trentxintong@devbig460.frc2.facebook.com> | 2018-05-17 17:49:06 -0700 |
|---|---|---|
| committer | Facebook Github Bot <facebook-github-bot@users.noreply.github.com> | 2018-05-17 17:57:48 -0700 |
| commit | aed7abbcca7574ed438c3b22e27db9bf249e8de3 (patch) | |
| tree | 537d2c0347a06fc0e2f6a871e4370115cc598451 /memtable | |
| parent | fa43948cbc7fd41b6e67099c3ea96597d9af5bd9 (diff) | |
Reorder field based on esan data
Summary:
Running. TEST_TMPDIR=/dev/shm ./buck-out/gen/rocks/tools/rocks_db_bench --benchmarks=readwhilewriting --num=5000000 -benchmark_write_rate_limit=2000000 --threads=32
Collected esan data and reorder field. Accesses to 4th and 6th fields take majority of the access. Group them. Overall, this struct takes 10%+ of the total accesses in the program. (637773011/6107964986)
==2433831== class rocksdb::InlineSkipList
==2433831== size = 48, count = 637773011, ratio = 112412, array access = 0
==2433831== # 0: offset = 0, size = 2, count = 455137, type = i16
==2433831== # 1: offset = 2, size = 2, count = 6, type = i16
==2433831== # 2: offset = 4, size = 4, count = 182303, type = i32
==2433831== # 3: offset = 8, size = 8, count = 263953900, type = %"class.rocksdb::MemTableRep::KeyComparator"*
==2433831== # 4: offset = 16, size = 8, count = 136409, type = %"class.rocksdb::Allocator"*
==2433831== # 5: offset = 24, size = 8, count = 366628820, type = %"struct.rocksdb::InlineSkipList<const rocksdb::MemTableRep::KeyComparator &>::Node"*
==2433831== # 6: offset = 32, size = 4, count = 6280031, type = %"struct.std::atomic" = type { %"struct.std::__atomic_base" }
==2433831== # 7: offset = 40, size = 8, count = 136405, type = %"struct.rocksdb::InlineSkipList<const rocksdb::MemTableRep::KeyComparator &>::Splice"*
==2433831==EfficiencySanitizer: total struct field access count = 6107964986
Before re-ordering
[trentxintong@devbig460.frc2 ~/fbsource/fbcode]$ fgrep readwhilewriting
without-ro.log
readwhilewriting : 0.036 micros/op 27545605 ops/sec; 26.8 MB/s
(45954 of 5000000 found)
readwhilewriting : 0.036 micros/op 28024240 ops/sec; 27.2 MB/s
(43158 of 5000000 found)
readwhilewriting : 0.037 micros/op 27345145 ops/sec; 27.1 MB/s
(46725 of 5000000 found)
readwhilewriting : 0.037 micros/op 27072588 ops/sec; 27.3 MB/s
(42605 of 5000000 found)
readwhilewriting : 0.034 micros/op 29578781 ops/sec; 28.3 MB/s
(44294 of 5000000 found)
readwhilewriting : 0.035 micros/op 28528304 ops/sec; 27.7 MB/s
(44176 of 5000000 found)
readwhilewriting : 0.037 micros/op 27075497 ops/sec; 26.5 MB/s
(43763 of 5000000 found)
readwhilewriting : 0.036 micros/op 28024117 ops/sec; 27.1 MB/s
(40622 of 5000000 found)
readwhilewriting : 0.037 micros/op 27078709 ops/sec; 27.6 MB/s
(47774 of 5000000 found)
readwhilewriting : 0.034 micros/op 29020689 ops/sec; 28.1 MB/s
(45066 of 5000000 found)
AVERAGE()=27.37 MB/s
After re-ordering
[trentxintong@devbig460.frc2 ~/fbsource/fbcode]$ fgrep readwhilewriting
ro.log
readwhilewriting : 0.036 micros/op 27542409 ops/sec; 27.7 MB/s
(46163 of 5000000 found)
readwhilewriting : 0.036 micros/op 28021148 ops/sec; 28.2 MB/s
(46155 of 5000000 found)
readwhilewriting : 0.036 micros/op 28021035 ops/sec; 27.3 MB/s
(44039 of 5000000 found)
readwhilewriting : 0.036 micros/op 27538659 ops/sec; 27.5 MB/s
(46781 of 5000000 found)
readwhilewriting : 0.036 micros/op 28028604 ops/sec; 27.6 MB/s
(44689 of 5000000 found)
readwhilewriting : 0.036 micros/op 27541452 ops/sec; 27.3 MB/s
(43156 of 5000000 found)
readwhilewriting : 0.034 micros/op 29041338 ops/sec; 28.8 MB/s
(44895 of 5000000 found)
readwhilewriting : 0.036 micros/op 27784974 ops/sec; 26.3 MB/s
(39963 of 5000000 found)
readwhilewriting : 0.036 micros/op 27538892 ops/sec; 28.1 MB/s
(46570 of 5000000 found)
readwhilewriting : 0.038 micros/op 26622473 ops/sec; 27.0 MB/s
(43236 of 5000000 found)
AVERAGE()=27.58 MB/s
Closes https://github.com/facebook/rocksdb/pull/3855
Reviewed By: siying
Differential Revision: D8048781
Pulled By: trentxintong
fbshipit-source-id: bc9807a9845e2a92cb171ce1ecb5a2c8a51f1481
Diffstat (limited to 'memtable')
| -rw-r--r-- | memtable/inlineskiplist.h | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/memtable/inlineskiplist.h b/memtable/inlineskiplist.h index d3ee1f70e..1ef8f2b6d 100644 --- a/memtable/inlineskiplist.h +++ b/memtable/inlineskiplist.h @@ -184,10 +184,9 @@ class InlineSkipList { const uint16_t kBranching_; const uint32_t kScaledInverseBranching_; + Allocator* const allocator_; // Allocator used for allocations of nodes // Immutable after construction Comparator const compare_; - Allocator* const allocator_; // Allocator used for allocations of nodes - Node* const head_; // Modified only by Insert(). Read racily by readers, but stale @@ -587,8 +586,8 @@ InlineSkipList<Comparator>::InlineSkipList(const Comparator cmp, : kMaxHeight_(static_cast<uint16_t>(max_height)), kBranching_(static_cast<uint16_t>(branching_factor)), kScaledInverseBranching_((Random::kMaxNext + 1) / kBranching_), - compare_(cmp), allocator_(allocator), + compare_(cmp), head_(AllocateNode(0, max_height)), max_height_(1), seq_splice_(AllocateSplice()) { |