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Hello and thanks for RocksDB, When log_write_bench is run with the -bytes_per_sync option, the option does not influence any *sync* behaviour. > strace -e trace=write,sync_file_range ./log_write_bench -record_interval 0 -record_size 1048576 -num_records 11 -bytes_per_sync 2097152 2>&1 | egrep '^(sync|write.*XXXX)' write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 I suspect that this is because the bytes_per_sync option now needs to be using a `WritableFileWriter` and not a `WritableFile`. With the diff below applied, it changes to: > strace -e trace=write,sync_file_range ./log_write_bench -record_interval 0 -record_size 1048576 -num_records 11 -bytes_per_sync 2097152 2>&1 | egrep '^(sync|write.*XXXX)' write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 sync_file_range(0x3, 0, 0x200000, 0x2) = 0 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 sync_file_range(0x3, 0x200000, 0x200000, 0x2) = 0 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 sync_file_range(0x3, 0x400000, 0x200000, 0x2) = 0 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 sync_file_range(0x3, 0x600000, 0x200000, 0x2) = 0 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 sync_file_range(0x3, 0x800000, 0x200000, 0x2) = 0 ( Note that the first 1MB is not synced as mentioned in util/file_reader_writer.cc::WritableFileWriter::Flush() ) This diff also includes the fix from https://github.com/facebook/rocksdb/pull/1373 > diff -du util/log_write_bench.cc.orig util/log_write_bench.cc --- util/log_write_bench.cc.orig 2016-10-04 12:06:29.115122580 -0400 +++ util/log_write_bench.cc 2016-10-05 07:24:09.677037576 -0400 @@ -14,6 +14,7 @@ #include <gflags/gflags.h> #include "rocksdb/env.h" +#include "util/file_reader_writer.h" #include "util/histogram.h" #include "util/testharness.h" #include "util/testutil.h" @@ -38,19 +39,21 @@ env_options.bytes_per_sync = FLAGS_bytes_per_sync; unique_ptr<WritableFile> file; env->NewWritableFile(file_name, &file, env_options); + unique_ptr<WritableFileWriter> writer; + writer.reset(new WritableFileWriter(std::move(file), env_options)); std::string record; - record.assign('X', FLAGS_record_size); + record.assign(FLAGS_record_size, 'X'); HistogramImpl hist; uint64_t start_time = env->NowMicros(); for (int i = 0; i < FLAGS_num_records; i++) { uint64_t start_nanos = env->NowNanos(); - file->Append(record); - file->Flush(); + writer->Append(record); + writer->Flush(); if (FLAGS_enable_sync) { - file->Sync(); + writer->Sync(false); } hist.Add(env->NowNanos() - start_nanos);
86 lines
2.5 KiB
C++
86 lines
2.5 KiB
C++
// Copyright (c) 2011-present, 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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#ifndef GFLAGS
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#include <cstdio>
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int main() {
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fprintf(stderr, "Please install gflags to run rocksdb tools\n");
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return 1;
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}
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#else
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#include <gflags/gflags.h>
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#include "rocksdb/env.h"
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#include "util/file_reader_writer.h"
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#include "util/histogram.h"
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#include "util/testharness.h"
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#include "util/testutil.h"
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using GFLAGS::ParseCommandLineFlags;
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using GFLAGS::SetUsageMessage;
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// A simple benchmark to simulate transactional logs
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DEFINE_int32(num_records, 6000, "Number of records.");
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DEFINE_int32(record_size, 249, "Size of each record.");
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DEFINE_int32(record_interval, 10000, "Interval between records (microSec)");
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DEFINE_int32(bytes_per_sync, 0, "bytes_per_sync parameter in EnvOptions");
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DEFINE_bool(enable_sync, false, "sync after each write.");
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namespace rocksdb {
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void RunBenchmark() {
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std::string file_name = test::TmpDir() + "/log_write_benchmark.log";
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Env* env = Env::Default();
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EnvOptions env_options;
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env_options.use_mmap_writes = false;
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env_options.bytes_per_sync = FLAGS_bytes_per_sync;
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unique_ptr<WritableFile> file;
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env->NewWritableFile(file_name, &file, env_options);
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unique_ptr<WritableFileWriter> writer;
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writer.reset(new WritableFileWriter(std::move(file), env_options));
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std::string record;
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record.assign(FLAGS_record_size, 'X');
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HistogramImpl hist;
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uint64_t start_time = env->NowMicros();
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for (int i = 0; i < FLAGS_num_records; i++) {
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uint64_t start_nanos = env->NowNanos();
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writer->Append(record);
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writer->Flush();
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if (FLAGS_enable_sync) {
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writer->Sync(false);
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}
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hist.Add(env->NowNanos() - start_nanos);
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if (i % 1000 == 1) {
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fprintf(stderr, "Wrote %d records...\n", i);
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}
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int time_to_sleep =
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(i + 1) * FLAGS_record_interval - (env->NowMicros() - start_time);
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if (time_to_sleep > 0) {
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env->SleepForMicroseconds(time_to_sleep);
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}
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}
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fprintf(stderr, "Distribution of latency of append+flush: \n%s",
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hist.ToString().c_str());
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}
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} // namespace rocksdb
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int main(int argc, char** argv) {
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SetUsageMessage(std::string("\nUSAGE:\n") + std::string(argv[0]) +
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" [OPTIONS]...");
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ParseCommandLineFlags(&argc, &argv, true);
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rocksdb::RunBenchmark();
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return 0;
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}
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#endif // GFLAGS
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