rocksdb/monitoring/iostats_context_imp.h
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

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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).
//
#pragma once
#include "monitoring/perf_step_timer.h"
#include "rocksdb/iostats_context.h"
#ifdef ROCKSDB_SUPPORT_THREAD_LOCAL
namespace ROCKSDB_NAMESPACE {
extern __thread IOStatsContext iostats_context;
} // namespace ROCKSDB_NAMESPACE
// increment a specific counter by the specified value
#define IOSTATS_ADD(metric, value) (iostats_context.metric += value)
// Increase metric value only when it is positive
#define IOSTATS_ADD_IF_POSITIVE(metric, value) \
if (value > 0) { IOSTATS_ADD(metric, value); }
// reset a specific counter to zero
#define IOSTATS_RESET(metric) (iostats_context.metric = 0)
// reset all counters to zero
#define IOSTATS_RESET_ALL() (iostats_context.Reset())
#define IOSTATS_SET_THREAD_POOL_ID(value) \
(iostats_context.thread_pool_id = value)
#define IOSTATS_THREAD_POOL_ID() (iostats_context.thread_pool_id)
#define IOSTATS(metric) (iostats_context.metric)
// Declare and set start time of the timer
#define IOSTATS_TIMER_GUARD(metric) \
PerfStepTimer iostats_step_timer_##metric(&(iostats_context.metric)); \
iostats_step_timer_##metric.Start();
// Declare and set start time of the timer
#define IOSTATS_CPU_TIMER_GUARD(metric, clock) \
PerfStepTimer iostats_step_timer_##metric( \
&(iostats_context.metric), clock, true, \
PerfLevel::kEnableTimeAndCPUTimeExceptForMutex); \
iostats_step_timer_##metric.Start();
#else // ROCKSDB_SUPPORT_THREAD_LOCAL
#define IOSTATS_ADD(metric, value)
#define IOSTATS_ADD_IF_POSITIVE(metric, value)
#define IOSTATS_RESET(metric)
#define IOSTATS_RESET_ALL()
#define IOSTATS_SET_THREAD_POOL_ID(value)
#define IOSTATS_THREAD_POOL_ID()
#define IOSTATS(metric) 0
#define IOSTATS_TIMER_GUARD(metric)
#define IOSTATS_CPU_TIMER_GUARD(metric, clock) static_cast<void>(clock)
#endif // ROCKSDB_SUPPORT_THREAD_LOCAL