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/*
* Copyright (c) 2012 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 "webrtc/system_wrappers/source/thread_posix.h"
#include <algorithm>
#include <errno.h>
#include <unistd.h>
#ifdef WEBRTC_LINUX
#include <linux/unistd.h>
#include <sched.h>
#include <sys/types.h>
#endif
#include "webrtc/base/checks.h"
#include "webrtc/base/platform_thread.h"
#include "webrtc/system_wrappers/include/critical_section_wrapper.h"
#include "webrtc/system_wrappers/include/event_wrapper.h"
#include "webrtc/system_wrappers/include/sleep.h"
#include "webrtc/system_wrappers/include/trace.h"
namespace webrtc {
namespace {
struct ThreadAttributes {
ThreadAttributes() { pthread_attr_init(&attr); }
~ThreadAttributes() { pthread_attr_destroy(&attr); }
pthread_attr_t* operator&() { return &attr; }
pthread_attr_t attr;
};
} // namespace
int ConvertToSystemPriority(ThreadPriority priority, int min_prio,
int max_prio) {
RTC_DCHECK(max_prio - min_prio > 2);
const int top_prio = max_prio - 1;
const int low_prio = min_prio + 1;
switch (priority) {
case kLowPriority:
return low_prio;
case kNormalPriority:
// The -1 ensures that the kHighPriority is always greater or equal to
// kNormalPriority.
return (low_prio + top_prio - 1) / 2;
case kHighPriority:
return std::max(top_prio - 2, low_prio);
case kHighestPriority:
return std::max(top_prio - 1, low_prio);
case kRealtimePriority:
return top_prio;
}
RTC_DCHECK(false);
return low_prio;
}
// static
void* ThreadPosix::StartThread(void* param) {
static_cast<ThreadPosix*>(param)->Run();
return 0;
}
ThreadPosix::ThreadPosix(ThreadRunFunction func, void* obj,
const char* thread_name)
: run_function_(func),
obj_(obj),
stop_event_(false, false),
name_(thread_name ? thread_name : "webrtc"),
thread_(0) {
RTC_DCHECK(name_.length() < 64);
}
uint32_t ThreadWrapper::GetThreadId() {
return rtc::CurrentThreadId();
}
ThreadPosix::~ThreadPosix() {
RTC_DCHECK(thread_checker_.CalledOnValidThread());
}
// TODO(pbos): Make Start void, calling code really doesn't support failures
// here.
bool ThreadPosix::Start() {
RTC_DCHECK(thread_checker_.CalledOnValidThread());
RTC_DCHECK(!thread_) << "Thread already started?";
ThreadAttributes attr;
// Set the stack stack size to 1M.
pthread_attr_setstacksize(&attr, 1024 * 1024);
RTC_CHECK_EQ(0, pthread_create(&thread_, &attr, &StartThread, this));
return true;
}
bool ThreadPosix::Stop() {
RTC_DCHECK(thread_checker_.CalledOnValidThread());
if (!thread_)
return true;
stop_event_.Set();
RTC_CHECK_EQ(0, pthread_join(thread_, nullptr));
thread_ = 0;
return true;
}
bool ThreadPosix::SetPriority(ThreadPriority priority) {
RTC_DCHECK(thread_checker_.CalledOnValidThread());
if (!thread_)
return false;
#if defined(WEBRTC_CHROMIUM_BUILD) && defined(WEBRTC_LINUX)
// TODO(tommi): Switch to the same mechanism as Chromium uses for
// changing thread priorities.
return true;
#else
#ifdef WEBRTC_THREAD_RR
const int policy = SCHED_RR;
#else
const int policy = SCHED_FIFO;
#endif
const int min_prio = sched_get_priority_min(policy);
const int max_prio = sched_get_priority_max(policy);
if (min_prio == -1 || max_prio == -1) {
WEBRTC_TRACE(kTraceError, kTraceUtility, -1,
"unable to retreive min or max priority for threads");
return false;
}
if (max_prio - min_prio <= 2)
return false;
sched_param param;
param.sched_priority = ConvertToSystemPriority(priority, min_prio, max_prio);
if (pthread_setschedparam(thread_, policy, ¶m) != 0) {
WEBRTC_TRACE(
kTraceError, kTraceUtility, -1, "unable to set thread priority");
return false;
}
return true;
#endif // defined(WEBRTC_CHROMIUM_BUILD) && defined(WEBRTC_LINUX)
}
void ThreadPosix::Run() {
if (!name_.empty()) {
// Setting the thread name may fail (harmlessly) if running inside a
// sandbox. Ignore failures if they happen.
rtc::SetCurrentThreadName(name_.substr(0, 63).c_str());
}
// It's a requirement that for successful thread creation that the run
// function be called at least once (see RunFunctionIsCalled unit test),
// so to fullfill that requirement, we use a |do| loop and not |while|.
do {
if (!run_function_(obj_))
break;
} while (!stop_event_.Wait(0));
}
} // namespace webrtc
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