webrtc/rtc_base/synchronization/yield.cc
Markus Handell f70fbc8411 Introduces rtc_base/synchronization/mutex.h.
This change introduces a new non-reentrant mutex to WebRTC. It
enables eventual migration to Abseil's mutex.

The mutex types supportable by webrtc::Mutex are

- absl::Mutex
- CriticalSection (Windows only)
- pthread_mutex (POSIX only)

In addition to introducing the mutexes, the CL also changes
PacketBuffer to use the new mutex instead of rtc::CriticalSection.

The method of yielding from critical_section.cc was given a
mini-cleanup and YieldCurrentThread() was added to
rtc_base/synchronization/yield.h/cc.

Additionally, google_benchmark benchmarks for the mutexes were added
(test courtesy of danilchap@), and some results from a pthread/Abseil
shootout were added showing Abseil has the advantage in higher
contention.

Bug: webrtc:11567, webrtc:11634
Change-Id: Iaec324ccb32ec3851bf6db3fd290f5ea5dee4c81
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/176230
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Tommi <tommi@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31443}
2020-06-04 09:55:12 +00:00

36 lines
976 B
C++

/*
* Copyright 2020 The WebRTC Project Authors. All rights reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "rtc_base/synchronization/yield.h"
#if defined(WEBRTC_WIN)
#include <windows.h>
#else
#include <sched.h>
#include <time.h>
#endif
namespace webrtc {
void YieldCurrentThread() {
// TODO(bugs.webrtc.org/11634): use dedicated OS functionality instead of
// sleep for yielding.
#if defined(WEBRTC_WIN)
::Sleep(0);
#elif defined(WEBRTC_MAC) && defined(RTC_USE_NATIVE_MUTEX_ON_MAC) && \
!RTC_USE_NATIVE_MUTEX_ON_MAC
sched_yield();
#else
static const struct timespec ts_null = {0};
nanosleep(&ts_null, nullptr);
#endif
}
} // namespace webrtc