Move base to DEPS

base/threading/thread_perftest.cc

-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "base/base_switches.h"
-#include "base/bind.h"
-#include "base/command_line.h"
-#include "base/location.h"
-#include "base/memory/scoped_vector.h"
-#include "base/single_thread_task_runner.h"
-#include "base/strings/stringprintf.h"
-#include "base/synchronization/condition_variable.h"
-#include "base/synchronization/lock.h"
-#include "base/synchronization/waitable_event.h"
-#include "base/threading/thread.h"
-#include "base/time/time.h"
-#include "build/build_config.h"
-#include "testing/gtest/include/gtest/gtest.h"
-#include "testing/perf/perf_test.h"
-
-#if defined(OS_POSIX)
-#include <pthread.h>
-#endif
-
-namespace base {
-
-namespace {
-
-const int kNumRuns = 100000;
-
-// Base class for a threading perf-test. This sets up some threads for the
-// test and measures the clock-time in addition to time spent on each thread.
-class ThreadPerfTest : public testing::Test {
- public:
-  ThreadPerfTest()
-      : done_(false, false) {
-    // Disable the task profiler as it adds significant cost!
-    CommandLine::Init(0, NULL);
-    CommandLine::ForCurrentProcess()->AppendSwitchASCII(
-        switches::kProfilerTiming,
-        switches::kProfilerTimingDisabledValue);
-  }
-
-  // To be implemented by each test. Subclass must uses threads_ such that
-  // their cpu-time can be measured. Test must return from PingPong() _and_
-  // call FinishMeasurement from any thread to complete the test.
-  virtual void Init() {}
-  virtual void PingPong(int hops) = 0;
-  virtual void Reset() {}
-
-  void TimeOnThread(base::ThreadTicks* ticks, base::WaitableEvent* done) {
-    *ticks = base::ThreadTicks::Now();
-    done->Signal();
-  }
-
-  base::ThreadTicks ThreadNow(base::Thread* thread) {
-    base::WaitableEvent done(false, false);
-    base::ThreadTicks ticks;
-    thread->task_runner()->PostTask(
-        FROM_HERE, base::Bind(&ThreadPerfTest::TimeOnThread,
-                              base::Unretained(this), &ticks, &done));
-    done.Wait();
-    return ticks;
-  }
-
-  void RunPingPongTest(const std::string& name, unsigned num_threads) {
-    // Create threads and collect starting cpu-time for each thread.
-    std::vector<base::ThreadTicks> thread_starts;
-    while (threads_.size() < num_threads) {
-      threads_.push_back(new base::Thread("PingPonger"));
-      threads_.back()->Start();
-      if (base::ThreadTicks::IsSupported())
-        thread_starts.push_back(ThreadNow(threads_.back()));
-    }
-
-    Init();
-
-    base::TimeTicks start = base::TimeTicks::Now();
-    PingPong(kNumRuns);
-    done_.Wait();
-    base::TimeTicks end = base::TimeTicks::Now();
-
-    // Gather the cpu-time spent on each thread. This does one extra tasks,
-    // but that should be in the noise given enough runs.
-    base::TimeDelta thread_time;
-    while (threads_.size()) {
-      if (base::ThreadTicks::IsSupported()) {
-        thread_time += ThreadNow(threads_.back()) - thread_starts.back();
-        thread_starts.pop_back();
-      }
-      threads_.pop_back();
-    }
-
-    Reset();
-
-    double num_runs = static_cast<double>(kNumRuns);
-    double us_per_task_clock = (end - start).InMicroseconds() / num_runs;
-    double us_per_task_cpu = thread_time.InMicroseconds() / num_runs;
-
-    // Clock time per task.
-    perf_test::PrintResult(
-        "task", "", name + "_time ", us_per_task_clock, "us/hop", true);
-
-    // Total utilization across threads if available (likely higher).
-    if (base::ThreadTicks::IsSupported()) {
-      perf_test::PrintResult(
-          "task", "", name + "_cpu ", us_per_task_cpu, "us/hop", true);
-    }
-  }
-
- protected:
-  void FinishMeasurement() { done_.Signal(); }
-  ScopedVector<base::Thread> threads_;
-
- private:
-  base::WaitableEvent done_;
-};
-
-// Class to test task performance by posting empty tasks back and forth.
-class TaskPerfTest : public ThreadPerfTest {
-  base::Thread* NextThread(int count) {
-    return threads_[count % threads_.size()];
-  }
-
-  void PingPong(int hops) override {
-    if (!hops) {
-      FinishMeasurement();
-      return;
-    }
-    NextThread(hops)->task_runner()->PostTask(
-        FROM_HERE, base::Bind(&ThreadPerfTest::PingPong, base::Unretained(this),
-                              hops - 1));
-  }
-};
-
-// This tries to test the 'best-case' as well as the 'worst-case' task posting
-// performance. The best-case keeps one thread alive such that it never yeilds,
-// while the worse-case forces a context switch for every task. Four threads are
-// used to ensure the threads do yeild (with just two it might be possible for
-// both threads to stay awake if they can signal each other fast enough).
-TEST_F(TaskPerfTest, TaskPingPong) {
-  RunPingPongTest("1_Task_Threads", 1);
-  RunPingPongTest("4_Task_Threads", 4);
-}
-
-
-// Same as above, but add observers to test their perf impact.
-class MessageLoopObserver : public base::MessageLoop::TaskObserver {
- public:
-  void WillProcessTask(const base::PendingTask& pending_task) override {}
-  void DidProcessTask(const base::PendingTask& pending_task) override {}
-};
-MessageLoopObserver message_loop_observer;
-
-class TaskObserverPerfTest : public TaskPerfTest {
- public:
-  void Init() override {
-    TaskPerfTest::Init();
-    for (size_t i = 0; i < threads_.size(); i++) {
-      threads_[i]->message_loop()->AddTaskObserver(&message_loop_observer);
-    }
-  }
-};
-
-TEST_F(TaskObserverPerfTest, TaskPingPong) {
-  RunPingPongTest("1_Task_Threads_With_Observer", 1);
-  RunPingPongTest("4_Task_Threads_With_Observer", 4);
-}
-
-// Class to test our WaitableEvent performance by signaling back and fort.
-// WaitableEvent is templated so we can also compare with other versions.
-template <typename WaitableEventType>
-class EventPerfTest : public ThreadPerfTest {
- public:
-  void Init() override {
-    for (size_t i = 0; i < threads_.size(); i++)
-      events_.push_back(new WaitableEventType(false, false));
-  }
-
-  void Reset() override { events_.clear(); }
-
-  void WaitAndSignalOnThread(size_t event) {
-    size_t next_event = (event + 1) % events_.size();
-    int my_hops = 0;
-    do {
-      events_[event]->Wait();
-      my_hops = --remaining_hops_;  // We own 'hops' between Wait and Signal.
-      events_[next_event]->Signal();
-    } while (my_hops > 0);
-    // Once we are done, all threads will signal as hops passes zero.
-    // We only signal completion once, on the thread that reaches zero.
-    if (!my_hops)
-      FinishMeasurement();
-  }
-
-  void PingPong(int hops) override {
-    remaining_hops_ = hops;
-    for (size_t i = 0; i < threads_.size(); i++) {
-      threads_[i]->task_runner()->PostTask(
-          FROM_HERE, base::Bind(&EventPerfTest::WaitAndSignalOnThread,
-                                base::Unretained(this), i));
-    }
-
-    // Kick off the Signal ping-ponging.
-    events_.front()->Signal();
-  }
-
-  int remaining_hops_;
-  ScopedVector<WaitableEventType> events_;
-};
-
-// Similar to the task posting test, this just tests similar functionality
-// using WaitableEvents. We only test four threads (worst-case), but we
-// might want to craft a way to test the best-case (where the thread doesn't
-// end up blocking because the event is already signalled).
-typedef EventPerfTest<base::WaitableEvent> WaitableEventPerfTest;
-TEST_F(WaitableEventPerfTest, EventPingPong) {
-  RunPingPongTest("4_WaitableEvent_Threads", 4);
-}
-
-// Build a minimal event using ConditionVariable.
-class ConditionVariableEvent {
- public:
-  ConditionVariableEvent(bool manual_reset, bool initially_signaled)
-      : cond_(&lock_), signaled_(false) {
-    DCHECK(!manual_reset);
-    DCHECK(!initially_signaled);
-  }
-
-  void Signal() {
-    {
-      base::AutoLock scoped_lock(lock_);
-      signaled_ = true;
-    }
-    cond_.Signal();
-  }
-
-  void Wait() {
-    base::AutoLock scoped_lock(lock_);
-    while (!signaled_)
-      cond_.Wait();
-    signaled_ = false;
-  }
-
- private:
-  base::Lock lock_;
-  base::ConditionVariable cond_;
-  bool signaled_;
-};
-
-// This is meant to test the absolute minimal context switching time
-// using our own base synchronization code.
-typedef EventPerfTest<ConditionVariableEvent> ConditionVariablePerfTest;
-TEST_F(ConditionVariablePerfTest, EventPingPong) {
-  RunPingPongTest("4_ConditionVariable_Threads", 4);
-}
-#if defined(OS_POSIX)
-
-// Absolutely 100% minimal posix waitable event. If there is a better/faster
-// way to force a context switch, we should use that instead.
-class PthreadEvent {
- public:
-  PthreadEvent(bool manual_reset, bool initially_signaled) {
-    DCHECK(!manual_reset);
-    DCHECK(!initially_signaled);
-    pthread_mutex_init(&mutex_, 0);
-    pthread_cond_init(&cond_, 0);
-    signaled_ = false;
-  }
-
-  ~PthreadEvent() {
-    pthread_cond_destroy(&cond_);
-    pthread_mutex_destroy(&mutex_);
-  }
-
-  void Signal() {
-    pthread_mutex_lock(&mutex_);
-    signaled_ = true;
-    pthread_mutex_unlock(&mutex_);
-    pthread_cond_signal(&cond_);
-  }
-
-  void Wait() {
-    pthread_mutex_lock(&mutex_);
-    while (!signaled_)
-      pthread_cond_wait(&cond_, &mutex_);
-    signaled_ = false;
-    pthread_mutex_unlock(&mutex_);
-  }
-
- private:
-  bool signaled_;
-  pthread_mutex_t mutex_;
-  pthread_cond_t cond_;
-};
-
-// This is meant to test the absolute minimal context switching time.
-// If there is any faster way to do this we should substitute it in.
-typedef EventPerfTest<PthreadEvent> PthreadEventPerfTest;
-TEST_F(PthreadEventPerfTest, EventPingPong) {
-  RunPingPongTest("4_PthreadCondVar_Threads", 4);
-}
-
-#endif
-
-}  // namespace
-
-}  // namespace base