[RocksDB] Simplify StopWatch implementation

Summary:
Make stop watch a simple implementation, instead of subclass of a virtual class
Allocate stop watches off the stack instead of heap.
Code is more terse now.

Test Plan: make all check, db_bench with --statistics=1

Reviewers: haobo, dhruba

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D10809
main
Abhishek Kona 12 years ago
parent 446151cd20
commit e1174306c5
  1. 8
      db/db_impl.cc
  2. 59
      util/stop_watch.h

@ -1930,9 +1930,7 @@ Status DBImpl::Get(const ReadOptions& options,
std::string* value) {
Status s;
std::unique_ptr<StopWatch> sw = stats::StartStopWatch(env_,
options_.statistics,
DB_GET);
StopWatch sw(env_, options_.statistics, DB_GET);
SequenceNumber snapshot;
MutexLock l(&mutex_);
if (options.snapshot != nullptr) {
@ -2025,9 +2023,7 @@ Status DBImpl::Write(const WriteOptions& options, WriteBatch* my_batch) {
w.disableWAL = options.disableWAL;
w.done = false;
std::unique_ptr<StopWatch> sw = stats::StartStopWatch(env_,
options_.statistics,
DB_WRITE);
StopWatch sw(env_, options_.statistics, DB_WRITE);
MutexLock l(&mutex_);
writers_.push_back(&w);
while (!w.done && &w != writers_.front()) {

@ -3,41 +3,31 @@
#include "leveldb/env.h"
#include "leveldb/statistics.h"
#include <iostream>
namespace leveldb {
namespace leveldb {
// Auto-scoped.
// Records the statistic into the corresponding histogram.
class StopWatch {
public:
virtual uint64_t ElapsedMicros() = 0;
virtual ~StopWatch() {}
};
StopWatch(
Env * const env,
std::shared_ptr<Statistics> statistics,
const Histograms histogram_name) :
env_(env),
start_time_(env->NowMicros()),
statistics_(statistics),
histogram_name_(histogram_name) {}
class DoNothingStopWatch : public StopWatch {
public:
virtual uint64_t ElapsedMicros() {
return 0;
}
};
// Auto-scoped.
// Records the statistic into the corresponding histogram.
class ScopedRecordingStopWatch : public StopWatch {
public:
ScopedRecordingStopWatch(Env * const env,
std::shared_ptr<Statistics> statistics,
const Histograms histogram_name) :
env_(env),
start_time_(env->NowMicros()),
statistics_(statistics),
histogram_name_(histogram_name) {}
virtual uint64_t ElapsedMicros() {
uint64_t ElapsedMicros() {
return env_->NowMicros() - start_time_;
}
virtual ~ScopedRecordingStopWatch() {
uint64_t elapsed_time = env_->NowMicros() - start_time_;
statistics_->measureTime(histogram_name_, elapsed_time);
~StopWatch() {
if (statistics_) {
statistics_->measureTime(histogram_name_, ElapsedMicros());
}
}
private:
@ -47,22 +37,5 @@ class ScopedRecordingStopWatch : public StopWatch {
const Histograms histogram_name_;
};
namespace stats {
// Helper method
std::unique_ptr<StopWatch> StartStopWatch(Env * const env,
std::shared_ptr<Statistics> stats,
Histograms histogram_name) {
assert(env);
if (stats) {
return std::unique_ptr<StopWatch>(new ScopedRecordingStopWatch(
env,
stats,
histogram_name));
} else {
return std::unique_ptr<StopWatch>(new DoNothingStopWatch());
}
};
} // namespace stats
} // namespace leveldb
#endif // STORAGE_LEVELDB_UTIL_STOP_WATCH_H_

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