Introduce a SchedulerHelper in content/child/scheduler

content/renderer/scheduler/task_queue_manager_perftest.cc

-// Copyright 2015 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 "content/renderer/scheduler/task_queue_manager.h"
-
-#include "base/bind.h"
-#include "base/threading/thread.h"
-#include "content/renderer/scheduler/renderer_scheduler_message_loop_delegate.h"
-#include "content/renderer/scheduler/task_queue_selector.h"
-#include "testing/gtest/include/gtest/gtest.h"
-#include "testing/perf/perf_test.h"
-
-namespace content {
-
-namespace {
-
-class SelectorForTest : public TaskQueueSelector {
- public:
-  SelectorForTest() {}
-
-  void RegisterWorkQueues(
-      const std::vector<const base::TaskQueue*>& work_queues) override {
-    work_queues_ = work_queues;
-  }
-
-  bool SelectWorkQueueToService(size_t* out_queue_index) override {
-    // Choose the oldest task, if any.
-    bool found_one = false;
-    for (size_t i = 0; i < work_queues_.size(); i++) {
-      if (work_queues_[i]->empty())
-        continue;
-      // Note: the < comparison is correct due to the fact that the PendingTask
-      // operator inverts its comparison operation in order to work well in a
-      // heap based priority queue.
-      if (!found_one ||
-          work_queues_[*out_queue_index]->front() < work_queues_[i]->front())
-        *out_queue_index = i;
-      found_one = true;
-    }
-    CHECK(found_one);
-    return found_one;
-  }
-
-  void AsValueInto(base::trace_event::TracedValue* state) const override {}
-
- private:
-  std::vector<const base::TaskQueue*> work_queues_;
-
-  DISALLOW_COPY_AND_ASSIGN(SelectorForTest);
-};
-
-}  // namespace
-
-class TaskQueueManagerPerfTest : public testing::Test {
- public:
-  TaskQueueManagerPerfTest()
-      : num_queues_(0),
-        max_tasks_in_flight_(0),
-        num_tasks_in_flight_(0),
-        num_tasks_to_post_(0),
-        num_tasks_to_run_(0) {}
-
-  void Initialize(size_t num_queues) {
-    num_queues_ = num_queues;
-    message_loop_.reset(new base::MessageLoop());
-    selector_ = make_scoped_ptr(new SelectorForTest);
-    manager_ = make_scoped_ptr(new TaskQueueManager(
-        num_queues,
-        RendererSchedulerMessageLoopDelegate::Create(message_loop_.get()),
-        selector_.get()));
-  }
-
-  void TestDelayedTask() {
-    if (--num_tasks_to_run_ == 0) {
-      message_loop_->Quit();
-    }
-
-    num_tasks_in_flight_--;
-    // NOTE there are only up to max_tasks_in_flight_ pending delayed tasks at
-    // any one time.  Thanks to the lower_num_tasks_to_post going to zero if
-    // there are a lot of tasks in flight, the total number of task in flight at
-    // any one time is very variable.
-    unsigned int lower_num_tasks_to_post =
-        num_tasks_in_flight_ < (max_tasks_in_flight_ / 2) ? 1 : 0;
-    unsigned int max_tasks_to_post =
-        num_tasks_to_post_ % 2 ? lower_num_tasks_to_post : 10;
-    for (unsigned int i = 0;
-         i < max_tasks_to_post && num_tasks_in_flight_ < max_tasks_in_flight_ &&
-             num_tasks_to_post_ > 0;
-         i++) {
-      // Choose a queue weighted towards queue 0.
-      unsigned int queue = num_tasks_to_post_ % (num_queues_ + 1);
-      if (queue == num_queues_) {
-        queue = 0;
-      }
-      // Simulate a mix of short and longer delays.
-      unsigned int delay =
-          num_tasks_to_post_ % 2 ? 1 : (10 + num_tasks_to_post_ % 10);
-      scoped_refptr<base::SingleThreadTaskRunner> runner =
-          manager_->TaskRunnerForQueue(queue);
-      runner->PostDelayedTask(
-          FROM_HERE, base::Bind(&TaskQueueManagerPerfTest::TestDelayedTask,
-                                base::Unretained(this)),
-          base::TimeDelta::FromMicroseconds(delay));
-      num_tasks_in_flight_++;
-      num_tasks_to_post_--;
-    }
-  }
-
-  void ResetAndCallTestDelayedTask(unsigned int num_tasks_to_run) {
-    num_tasks_in_flight_ = 1;
-    num_tasks_to_post_ = num_tasks_to_run;
-    num_tasks_to_run_ = num_tasks_to_run;
-    TestDelayedTask();
-  }
-
-  void Benchmark(const std::string& trace, const base::Closure& test_task) {
-    base::TimeTicks start = base::TimeTicks::Now();
-    base::TimeTicks now;
-    unsigned long long num_iterations = 0;
-    do {
-      test_task.Run();
-      message_loop_->Run();
-      now = base::TimeTicks::Now();
-      num_iterations++;
-    } while (now - start < base::TimeDelta::FromSeconds(5));
-    perf_test::PrintResult(
-        "task", "", trace,
-        (now - start).InMicroseconds() / static_cast<double>(num_iterations),
-        "us/run", true);
-  }
-
-  size_t num_queues_;
-  unsigned int max_tasks_in_flight_;
-  unsigned int num_tasks_in_flight_;
-  unsigned int num_tasks_to_post_;
-  unsigned int num_tasks_to_run_;
-  scoped_ptr<SelectorForTest> selector_;
-  scoped_ptr<TaskQueueManager> manager_;
-  scoped_ptr<base::MessageLoop> message_loop_;
-};
-
-TEST_F(TaskQueueManagerPerfTest, RunTenThousandDelayedTasks_OneQueue) {
-  Initialize(1u);
-
-  max_tasks_in_flight_ = 200;
-  Benchmark("run 10000 delayed tasks with one queue",
-            base::Bind(&TaskQueueManagerPerfTest::ResetAndCallTestDelayedTask,
-                       base::Unretained(this), 10000));
-}
-
-TEST_F(TaskQueueManagerPerfTest, RunTenThousandDelayedTasks_FourQueues) {
-  Initialize(4u);
-
-  max_tasks_in_flight_ = 200;
-  Benchmark("run 10000 delayed tasks with four queues",
-            base::Bind(&TaskQueueManagerPerfTest::ResetAndCallTestDelayedTask,
-                       base::Unretained(this), 10000));
-}
-
-TEST_F(TaskQueueManagerPerfTest, RunTenThousandDelayedTasks_EightQueues) {
-  Initialize(8u);
-
-  max_tasks_in_flight_ = 200;
-  Benchmark("run 10000 delayed tasks with eight queues",
-            base::Bind(&TaskQueueManagerPerfTest::ResetAndCallTestDelayedTask,
-                       base::Unretained(this), 10000));
-}
-
-// TODO(alexclarke): Add additional tests with different mixes of non-delayed vs
-// delayed tasks.
-
-}  // namespace content