0f8b403eb5
The new constructor introduces two new changes:
* Support specifying thread priority at construction time.
- Moving forward, the SetPriority() method will be removed.
* New thread function type.
- The new type has 'void' as a return type and a polling loop
inside PlatformThread, is not used.
The old function type is still supported until all places have been moved over.
In this CL, the first steps towards deprecating the old mechanism are taken
by moving parts of the code that were simple to move, over to the new callback
type.
BUG=webrtc:7187
Review-Url: https://codereview.webrtc.org/2708723003
Cr-Commit-Position: refs/heads/master@{#16779}
137 lines
4.0 KiB
C++
137 lines
4.0 KiB
C++
/*
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* Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "webrtc/system_wrappers/include/critical_section_wrapper.h"
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#include "webrtc/base/platform_thread.h"
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#include "webrtc/system_wrappers/include/sleep.h"
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#include "webrtc/system_wrappers/include/trace.h"
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#include "webrtc/test/gtest.h"
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namespace webrtc {
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namespace {
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// Cause a process switch. Needed to avoid depending on
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// busy-wait in tests.
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static void SwitchProcess() {
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// Note - sched_yield has been tried as process switch. This does
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// not cause a process switch enough of the time for reliability.
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SleepMs(1);
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}
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class ProtectedCount {
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public:
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explicit ProtectedCount(CriticalSectionWrapper* crit_sect)
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: crit_sect_(crit_sect),
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count_(0) {
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}
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void Increment() {
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CriticalSectionScoped cs(crit_sect_);
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++count_;
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}
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int Count() const {
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CriticalSectionScoped cs(crit_sect_);
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return count_;
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}
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private:
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CriticalSectionWrapper* crit_sect_;
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int count_;
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};
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class CritSectTest : public ::testing::Test {
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public:
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CritSectTest() {}
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// Waits a number of cycles for the count to reach a given value.
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// Returns true if the target is reached or passed.
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bool WaitForCount(int target, ProtectedCount* count) {
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int loop_counter = 0;
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// On Posix, this SwitchProcess() needs to be in a loop to make the
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// test both fast and non-flaky.
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// With 1 us wait as the switch, up to 7 rounds have been observed.
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while (count->Count() < target && loop_counter < 100 * target) {
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++loop_counter;
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SwitchProcess();
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}
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return (count->Count() >= target);
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}
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};
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void LockUnlockThenStopRunFunction(void* obj) {
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ProtectedCount* the_count = static_cast<ProtectedCount*>(obj);
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the_count->Increment();
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}
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TEST_F(CritSectTest, ThreadWakesOnce) NO_THREAD_SAFETY_ANALYSIS {
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CriticalSectionWrapper* crit_sect =
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CriticalSectionWrapper::CreateCriticalSection();
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ProtectedCount count(crit_sect);
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rtc::PlatformThread thread(
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&LockUnlockThenStopRunFunction, &count, "ThreadWakesOnce");
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crit_sect->Enter();
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thread.Start();
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SwitchProcess();
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// The critical section is of reentrant mode, so this should not release
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// the lock, even though count.Count() locks and unlocks the critical section
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// again.
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// Thus, the thread should not be able to increment the count
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ASSERT_EQ(0, count.Count());
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crit_sect->Leave(); // This frees the thread to act.
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EXPECT_TRUE(WaitForCount(1, &count));
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thread.Stop();
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delete crit_sect;
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}
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bool LockUnlockRunFunction(void* obj) {
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ProtectedCount* the_count = static_cast<ProtectedCount*>(obj);
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the_count->Increment();
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SwitchProcess();
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return true;
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}
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TEST_F(CritSectTest, ThreadWakesTwice) NO_THREAD_SAFETY_ANALYSIS {
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CriticalSectionWrapper* crit_sect =
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CriticalSectionWrapper::CreateCriticalSection();
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ProtectedCount count(crit_sect);
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rtc::PlatformThread thread(
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&LockUnlockRunFunction, &count, "ThreadWakesTwice");
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crit_sect->Enter(); // Make sure counter stays 0 until we wait for it.
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thread.Start();
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crit_sect->Leave();
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// The thread is capable of grabbing the lock multiple times,
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// incrementing counter once each time.
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// It's possible for the count to be incremented by more than 2.
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EXPECT_TRUE(WaitForCount(2, &count));
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EXPECT_LE(2, count.Count());
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// The thread does not increment while lock is held.
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crit_sect->Enter();
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int count_before = count.Count();
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for (int i = 0; i < 10; i++) {
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SwitchProcess();
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}
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EXPECT_EQ(count_before, count.Count());
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crit_sect->Leave();
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SwitchProcess();
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EXPECT_TRUE(WaitForCount(count_before + 1, &count));
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thread.Stop();
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delete crit_sect;
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}
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} // anonymous namespace
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} // namespace webrtc
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