rocksdb/monitoring/instrumented_mutex.cc
mrambacher 3dff28cf9b Use SystemClock* instead of std::shared_ptr<SystemClock> in lower level routines (#8033)
Summary:
For performance purposes, the lower level routines were changed to use a SystemClock* instead of a std::shared_ptr<SystemClock>.  The shared ptr has some performance degradation on certain hardware classes.

For most of the system, there is no risk of the pointer being deleted/invalid because the shared_ptr will be stored elsewhere.  For example, the ImmutableDBOptions stores the Env which has a std::shared_ptr<SystemClock> in it.  The SystemClock* within the ImmutableDBOptions is essentially a "short cut" to gain access to this constant resource.

There were a few classes (PeriodicWorkScheduler?) where the "short cut" property did not hold.  In those cases, the shared pointer was preserved.

Using db_bench readrandom perf_level=3 on my EC2 box, this change performed as well or better than 6.17:

6.17: readrandom   :      28.046 micros/op 854902 ops/sec;   61.3 MB/s (355999 of 355999 found)
6.18: readrandom   :      32.615 micros/op 735306 ops/sec;   52.7 MB/s (290999 of 290999 found)
PR: readrandom   :      27.500 micros/op 871909 ops/sec;   62.5 MB/s (367999 of 367999 found)

(Note that the times for 6.18 are prior to revert of the SystemClock).

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8033

Reviewed By: pdillinger

Differential Revision: D27014563

Pulled By: mrambacher

fbshipit-source-id: ad0459eba03182e454391b5926bf5cdd45657b67
2021-03-15 04:34:11 -07:00

74 lines
2.1 KiB
C++

// 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).
#include "monitoring/instrumented_mutex.h"
#include "monitoring/perf_context_imp.h"
#include "monitoring/thread_status_util.h"
#include "rocksdb/system_clock.h"
#include "test_util/sync_point.h"
namespace ROCKSDB_NAMESPACE {
namespace {
#ifndef NPERF_CONTEXT
Statistics* stats_for_report(SystemClock* clock, Statistics* stats) {
if (clock != nullptr && stats != nullptr &&
stats->get_stats_level() > kExceptTimeForMutex) {
return stats;
} else {
return nullptr;
}
}
#endif // NPERF_CONTEXT
} // namespace
void InstrumentedMutex::Lock() {
PERF_CONDITIONAL_TIMER_FOR_MUTEX_GUARD(
db_mutex_lock_nanos, stats_code_ == DB_MUTEX_WAIT_MICROS,
stats_for_report(clock_, stats_), stats_code_);
LockInternal();
}
void InstrumentedMutex::LockInternal() {
#ifndef NDEBUG
ThreadStatusUtil::TEST_StateDelay(ThreadStatus::STATE_MUTEX_WAIT);
#endif
mutex_.Lock();
}
void InstrumentedCondVar::Wait() {
PERF_CONDITIONAL_TIMER_FOR_MUTEX_GUARD(
db_condition_wait_nanos, stats_code_ == DB_MUTEX_WAIT_MICROS,
stats_for_report(clock_, stats_), stats_code_);
WaitInternal();
}
void InstrumentedCondVar::WaitInternal() {
#ifndef NDEBUG
ThreadStatusUtil::TEST_StateDelay(ThreadStatus::STATE_MUTEX_WAIT);
#endif
cond_.Wait();
}
bool InstrumentedCondVar::TimedWait(uint64_t abs_time_us) {
PERF_CONDITIONAL_TIMER_FOR_MUTEX_GUARD(
db_condition_wait_nanos, stats_code_ == DB_MUTEX_WAIT_MICROS,
stats_for_report(clock_, stats_), stats_code_);
return TimedWaitInternal(abs_time_us);
}
bool InstrumentedCondVar::TimedWaitInternal(uint64_t abs_time_us) {
#ifndef NDEBUG
ThreadStatusUtil::TEST_StateDelay(ThreadStatus::STATE_MUTEX_WAIT);
#endif
TEST_SYNC_POINT_CALLBACK("InstrumentedCondVar::TimedWaitInternal",
&abs_time_us);
return cond_.TimedWait(abs_time_us);
}
} // namespace ROCKSDB_NAMESPACE