rocksdb/util/stop_watch.h
Islam AbdelRahman d52f334cbd Break stalls when no bg work is happening
Summary:
Current stall will keep sleeping even if there is no Flush/Compactions to wait for, I changed the logic to break the stall if we are not flushing or compacting

db_bench command used
```
# fillrandom
# memtable size = 10MB
# value size = 1 MB
# num = 1000
# use /dev/shm
./db_bench --benchmarks="fillrandom,stats" --value_size=1048576 --write_buffer_size=10485760 --num=1000 --delayed_write_rate=XXXXX  --db="/dev/shm/new_stall" | grep "Cumulative stall"
```

```
Current results

# delayed_write_rate = 1000 Kb/sec
Cumulative stall: 00:00:9.031 H:M:S

# delayed_write_rate = 200 Kb/sec
Cumulative stall: 00:00:22.314 H:M:S

# delayed_write_rate = 100 Kb/sec
Cumulative stall: 00:00:42.784 H:M:S

# delayed_write_rate = 50 Kb/sec
Cumulative stall: 00:01:23.785 H:M:S

# delayed_write_rate = 25 Kb/sec
Cumulative stall: 00:02:45.702 H:M:S
```

```
New results

# delayed_write_rate = 1000 Kb/sec
Cumulative stall: 00:00:9.017 H:M:S

# delayed_write_rate = 200 Kb/sec
Cumulative stall: 00
Closes https://github.com/facebook/rocksdb/pull/1884

Differential Revision: D4585439

Pulled By: IslamAbdelRahman

fbshipit-source-id: aed2198
2017-03-16 18:24:17 -07:00

86 lines
2.4 KiB
C++

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
//
#pragma once
#include "rocksdb/env.h"
#include "util/statistics.h"
namespace rocksdb {
// Auto-scoped.
// Records the measure time into the corresponding histogram if statistics
// is not nullptr. It is also saved into *elapsed if the pointer is not nullptr
// and overwrite is true, it will be added to *elapsed if overwrite is false.
class StopWatch {
public:
StopWatch(Env* const env, Statistics* statistics, const uint32_t hist_type,
uint64_t* elapsed = nullptr, bool overwrite = true)
: env_(env),
statistics_(statistics),
hist_type_(hist_type),
elapsed_(elapsed),
overwrite_(overwrite),
stats_enabled_(statistics && statistics->HistEnabledForType(hist_type)),
start_time_((stats_enabled_ || elapsed != nullptr) ? env->NowMicros()
: 0) {}
~StopWatch() {
if (elapsed_) {
if (overwrite_) {
*elapsed_ = env_->NowMicros() - start_time_;
} else {
*elapsed_ += env_->NowMicros() - start_time_;
}
}
if (stats_enabled_) {
statistics_->measureTime(hist_type_,
(elapsed_ != nullptr) ? *elapsed_ :
(env_->NowMicros() - start_time_));
}
}
uint64_t start_time() const { return start_time_; }
private:
Env* const env_;
Statistics* statistics_;
const uint32_t hist_type_;
uint64_t* elapsed_;
bool overwrite_;
bool stats_enabled_;
const uint64_t start_time_;
};
// a nano second precision stopwatch
class StopWatchNano {
public:
explicit StopWatchNano(Env* const env, bool auto_start = false)
: env_(env), start_(0) {
if (auto_start) {
Start();
}
}
void Start() { start_ = env_->NowNanos(); }
uint64_t ElapsedNanos(bool reset = false) {
auto now = env_->NowNanos();
auto elapsed = now - start_;
if (reset) {
start_ = now;
}
return elapsed;
}
uint64_t ElapsedNanosSafe(bool reset = false) {
return (env_ != nullptr) ? ElapsedNanos(reset) : 0U;
}
private:
Env* const env_;
uint64_t start_;
};
} // namespace rocksdb