Revision aed7abbcca7574ed438c3b22e27db9bf249e8de3 authored by Xin Tong on 18 May 2018, 00:49:06 UTC, committed by Facebook Github Bot on 18 May 2018, 00:57:48 UTC
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
1 parent fa43948
internal_iterator.h
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
#pragma once
#include <string>
#include "rocksdb/comparator.h"
#include "rocksdb/iterator.h"
#include "rocksdb/status.h"
namespace rocksdb {
class PinnedIteratorsManager;
class InternalIterator : public Cleanable {
public:
InternalIterator() {}
virtual ~InternalIterator() {}
// An iterator is either positioned at a key/value pair, or
// not valid. This method returns true iff the iterator is valid.
// Always returns false if !status().ok().
virtual bool Valid() const = 0;
// Position at the first key in the source. The iterator is Valid()
// after this call iff the source is not empty.
virtual void SeekToFirst() = 0;
// Position at the last key in the source. The iterator is
// Valid() after this call iff the source is not empty.
virtual void SeekToLast() = 0;
// Position at the first key in the source that at or past target
// The iterator is Valid() after this call iff the source contains
// an entry that comes at or past target.
// All Seek*() methods clear any error status() that the iterator had prior to
// the call; after the seek, status() indicates only the error (if any) that
// happened during the seek, not any past errors.
virtual void Seek(const Slice& target) = 0;
// Position at the first key in the source that at or before target
// The iterator is Valid() after this call iff the source contains
// an entry that comes at or before target.
virtual void SeekForPrev(const Slice& target) = 0;
// Moves to the next entry in the source. After this call, Valid() is
// true iff the iterator was not positioned at the last entry in the source.
// REQUIRES: Valid()
virtual void Next() = 0;
// Moves to the previous entry in the source. After this call, Valid() is
// true iff the iterator was not positioned at the first entry in source.
// REQUIRES: Valid()
virtual void Prev() = 0;
// Return the key for the current entry. The underlying storage for
// the returned slice is valid only until the next modification of
// the iterator.
// REQUIRES: Valid()
virtual Slice key() const = 0;
// Return the value for the current entry. The underlying storage for
// the returned slice is valid only until the next modification of
// the iterator.
// REQUIRES: Valid()
virtual Slice value() const = 0;
// If an error has occurred, return it. Else return an ok status.
// If non-blocking IO is requested and this operation cannot be
// satisfied without doing some IO, then this returns Status::Incomplete().
virtual Status status() const = 0;
// True if the iterator is invalidated because it is out of the iterator
// upper bound
virtual bool IsOutOfBound() { return false; }
// Pass the PinnedIteratorsManager to the Iterator, most Iterators dont
// communicate with PinnedIteratorsManager so default implementation is no-op
// but for Iterators that need to communicate with PinnedIteratorsManager
// they will implement this function and use the passed pointer to communicate
// with PinnedIteratorsManager.
virtual void SetPinnedItersMgr(PinnedIteratorsManager* /*pinned_iters_mgr*/) {
}
// If true, this means that the Slice returned by key() is valid as long as
// PinnedIteratorsManager::ReleasePinnedData is not called and the
// Iterator is not deleted.
//
// IsKeyPinned() is guaranteed to always return true if
// - Iterator is created with ReadOptions::pin_data = true
// - DB tables were created with BlockBasedTableOptions::use_delta_encoding
// set to false.
virtual bool IsKeyPinned() const { return false; }
// If true, this means that the Slice returned by value() is valid as long as
// PinnedIteratorsManager::ReleasePinnedData is not called and the
// Iterator is not deleted.
virtual bool IsValuePinned() const { return false; }
virtual Status GetProperty(std::string /*prop_name*/, std::string* /*prop*/) {
return Status::NotSupported("");
}
protected:
void SeekForPrevImpl(const Slice& target, const Comparator* cmp) {
Seek(target);
if (!Valid()) {
SeekToLast();
}
while (Valid() && cmp->Compare(target, key()) < 0) {
Prev();
}
}
private:
// No copying allowed
InternalIterator(const InternalIterator&) = delete;
InternalIterator& operator=(const InternalIterator&) = delete;
};
// Return an empty iterator (yields nothing).
extern InternalIterator* NewEmptyInternalIterator();
// Return an empty iterator with the specified status.
extern InternalIterator* NewErrorInternalIterator(const Status& status);
} // namespace rocksdb
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