Reland "[scheduler] Add a perftest to measure basic scheduling costs."

This is a reland of 586e21ec

Original change's description:
> [scheduler] Add a perftest to measure basic scheduling costs.
> 
> Change-Id: Idda9f71ae005250848fd2a118e5c4344e36be452
> Reviewed-on: https://chromium-review.googlesource.com/1085295
> Reviewed-by: Alex Clarke <alexclarke@chromium.org>
> Commit-Queue: Alexander Timin <altimin@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#566362}

Change-Id: Ib9cfd16602c6bd0719059905250b91e0eb91dd22
Reviewed-on: https://chromium-review.googlesource.com/1097295Reviewed-by: Sami Kyöstilä <skyostil@chromium.org>
Commit-Queue: Alexander Timin <altimin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#567645}

third_party/blink/renderer/platform/scheduler/BUILD.gn

@@ -236,6 +236,7 @@ source_set("perf_tests") {
 
   sources = [
     "base/task_queue_manager_perftest.cc",
+    "test/scheduler_perftest.cc",
   ]
 
   deps = [

third_party/blink/renderer/platform/scheduler/main_thread/frame_scheduler_impl.cc

@@ -361,7 +361,7 @@ scoped_refptr<base::SingleThreadTaskRunner> FrameSchedulerImpl::GetTaskRunner(
   return nullptr;
 }
 
-scoped_refptr<TaskQueue> FrameSchedulerImpl::LoadingTaskQueue() {
+scoped_refptr<MainThreadTaskQueue> FrameSchedulerImpl::LoadingTaskQueue() {
   DCHECK(parent_page_scheduler_);
   if (!loading_task_queue_) {
     // TODO(panicker): Avoid adding this queue in RS task_runners_.
@@ -375,7 +375,8 @@ scoped_refptr<TaskQueue> FrameSchedulerImpl::LoadingTaskQueue() {
   return loading_task_queue_;
 }
 
-scoped_refptr<TaskQueue> FrameSchedulerImpl::LoadingControlTaskQueue() {
+scoped_refptr<MainThreadTaskQueue>
+FrameSchedulerImpl::LoadingControlTaskQueue() {
   DCHECK(parent_page_scheduler_);
   if (!loading_control_task_queue_) {
     loading_control_task_queue_ = main_thread_scheduler_->NewLoadingTaskQueue(
@@ -388,7 +389,7 @@ scoped_refptr<TaskQueue> FrameSchedulerImpl::LoadingControlTaskQueue() {
   return loading_control_task_queue_;
 }
 
-scoped_refptr<TaskQueue> FrameSchedulerImpl::ThrottleableTaskQueue() {
+scoped_refptr<MainThreadTaskQueue> FrameSchedulerImpl::ThrottleableTaskQueue() {
   DCHECK(parent_page_scheduler_);
   if (!throttleable_task_queue_) {
     // TODO(panicker): Avoid adding this queue in RS task_runners_.
@@ -418,7 +419,7 @@ scoped_refptr<TaskQueue> FrameSchedulerImpl::ThrottleableTaskQueue() {
   return throttleable_task_queue_;
 }
 
-scoped_refptr<TaskQueue> FrameSchedulerImpl::DeferrableTaskQueue() {
+scoped_refptr<MainThreadTaskQueue> FrameSchedulerImpl::DeferrableTaskQueue() {
   DCHECK(parent_page_scheduler_);
   if (!deferrable_task_queue_) {
     deferrable_task_queue_ = main_thread_scheduler_->NewTaskQueue(
@@ -437,7 +438,7 @@ scoped_refptr<TaskQueue> FrameSchedulerImpl::DeferrableTaskQueue() {
   return deferrable_task_queue_;
 }
 
-scoped_refptr<TaskQueue> FrameSchedulerImpl::PausableTaskQueue() {
+scoped_refptr<MainThreadTaskQueue> FrameSchedulerImpl::PausableTaskQueue() {
   DCHECK(parent_page_scheduler_);
   if (!pausable_task_queue_) {
     pausable_task_queue_ = main_thread_scheduler_->NewTaskQueue(
@@ -455,7 +456,7 @@ scoped_refptr<TaskQueue> FrameSchedulerImpl::PausableTaskQueue() {
   return pausable_task_queue_;
 }
 
-scoped_refptr<TaskQueue> FrameSchedulerImpl::UnpausableTaskQueue() {
+scoped_refptr<MainThreadTaskQueue> FrameSchedulerImpl::UnpausableTaskQueue() {
   DCHECK(parent_page_scheduler_);
   if (!unpausable_task_queue_) {
     unpausable_task_queue_ = main_thread_scheduler_->NewTaskQueue(
@@ -789,5 +790,10 @@ void FrameSchedulerImpl::RemovePauseSubresourceLoadingHandle() {
   }
 }
 
+scoped_refptr<MainThreadTaskQueue>
+FrameSchedulerImpl::GetTaskQueueForTesting() {
+  return UnpausableTaskQueue();
+}
+
 }  // namespace scheduler
 }  // namespace blink

third_party/blink/renderer/platform/scheduler/main_thread/frame_scheduler_impl.h

@@ -114,6 +114,10 @@ class PLATFORM_EXPORT FrameSchedulerImpl : public FrameScheduler {
   // page scheduler. Should be used only for testing purposes.
   FrameSchedulerImpl();
 
+  // Returns a valid per-frame task queue which should be used for testing.
+  // This task queue is expected to always run tasks.
+  scoped_refptr<MainThreadTaskQueue> GetTaskQueueForTesting();
+
  private:
   friend class PageSchedulerImpl;
   friend class main_thread_scheduler_impl_unittest::MainThreadSchedulerImplTest;
@@ -169,12 +173,12 @@ class PLATFORM_EXPORT FrameSchedulerImpl : public FrameScheduler {
   void AddPauseSubresourceLoadingHandle();
   void RemovePauseSubresourceLoadingHandle();
 
-  scoped_refptr<base::sequence_manager::TaskQueue> LoadingTaskQueue();
-  scoped_refptr<base::sequence_manager::TaskQueue> LoadingControlTaskQueue();
-  scoped_refptr<base::sequence_manager::TaskQueue> ThrottleableTaskQueue();
-  scoped_refptr<base::sequence_manager::TaskQueue> DeferrableTaskQueue();
-  scoped_refptr<base::sequence_manager::TaskQueue> PausableTaskQueue();
-  scoped_refptr<base::sequence_manager::TaskQueue> UnpausableTaskQueue();
+  scoped_refptr<MainThreadTaskQueue> LoadingTaskQueue();
+  scoped_refptr<MainThreadTaskQueue> LoadingControlTaskQueue();
+  scoped_refptr<MainThreadTaskQueue> ThrottleableTaskQueue();
+  scoped_refptr<MainThreadTaskQueue> DeferrableTaskQueue();
+  scoped_refptr<MainThreadTaskQueue> PausableTaskQueue();
+  scoped_refptr<MainThreadTaskQueue> UnpausableTaskQueue();
 
   const FrameScheduler::FrameType frame_type_;
 

third_party/blink/renderer/platform/scheduler/test/scheduler_perftest.cc

+// Copyright 2018 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/test/test_mock_time_task_runner.h"
+#include "base/time/default_tick_clock.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "testing/perf/perf_test.h"
+#include "third_party/blink/renderer/platform/scheduler/base/test/task_queue_manager_for_test.h"
+#include "third_party/blink/renderer/platform/scheduler/main_thread/main_thread_metrics_helper.h"
+#include "third_party/blink/renderer/platform/scheduler/main_thread/main_thread_scheduler_impl.h"
+
+namespace blink {
+namespace scheduler {
+
+class FrameSchedulerForTest : public FrameSchedulerImpl {
+ public:
+  FrameSchedulerForTest(MainThreadSchedulerImpl* main_thread_scheduler,
+                        PageSchedulerImpl* page_scheduler)
+      : FrameSchedulerImpl(main_thread_scheduler,
+                           page_scheduler,
+                           nullptr,
+                           FrameScheduler::FrameType::kMainFrame) {}
+
+  using FrameSchedulerImpl::GetTaskQueueForTesting;
+};
+
+class SchedulerPerfTest : public testing::Test {
+ protected:
+  void SetUp() override {
+    message_loop_ = std::make_unique<base::MessageLoop>();
+    main_thread_scheduler_ = std::make_unique<MainThreadSchedulerImpl>(
+        base::sequence_manager::TaskQueueManagerForTest::Create(
+            message_loop_.get(), message_loop_->task_runner(),
+            base::DefaultTickClock::GetInstance()),
+        base::nullopt);
+    metrics_helper_ = std::make_unique<MainThreadMetricsHelper>(
+        main_thread_scheduler_.get(), base::TimeTicks::Now(), false);
+    page_scheduler_ = std::make_unique<PageSchedulerImpl>(
+        nullptr, main_thread_scheduler_.get());
+    frame_scheduler_ = std::make_unique<FrameSchedulerForTest>(
+        main_thread_scheduler_.get(), page_scheduler_.get());
+  }
+
+  std::unique_ptr<base::MessageLoop> message_loop_;
+  std::unique_ptr<MainThreadSchedulerImpl> main_thread_scheduler_;
+  std::unique_ptr<MainThreadMetricsHelper> metrics_helper_;
+  std::unique_ptr<PageSchedulerImpl> page_scheduler_;
+  std::unique_ptr<FrameSchedulerForTest> frame_scheduler_;
+};
+
+void Measure(base::OnceCallback<void(size_t)> task,
+             size_t num_iterations,
+             std::string name) {
+  base::TimeTicks start = base::TimeTicks::Now();
+  base::ThreadTicks start_thread = base::ThreadTicks::Now();
+
+  std::move(task).Run(num_iterations);
+
+  base::TimeTicks now = base::TimeTicks::Now();
+  base::ThreadTicks now_thread = base::ThreadTicks::Now();
+
+  perf_test::PrintResult(
+      "task", "", name + " (wall time)",
+      (now - start).InMicroseconds() / static_cast<double>(num_iterations),
+      "us/run", true);
+  perf_test::PrintResult("task", "", name + " (thread time)",
+                         (now_thread - start_thread).InMicroseconds() /
+                             static_cast<double>(num_iterations),
+                         "us/run", true);
+}
+
+void RunChainedTask(scoped_refptr<base::SingleThreadTaskRunner> task_runner,
+                    size_t iterations) {
+  if (iterations <= 1)
+    return;
+  task_runner->PostTask(
+      FROM_HERE, base::BindOnce(&RunChainedTask, task_runner, iterations - 1));
+}
+
+TEST_F(SchedulerPerfTest, MeasureTimeCost) {
+  const size_t num_iterations = 1e5;
+
+  Measure(base::BindOnce([](size_t num_iterations) {
+            base::TimeTicks now;
+            for (size_t i = 0; i < num_iterations; ++i) {
+              now = base::TimeTicks::Now();
+            }
+          }),
+          num_iterations, "Measure wall time measurement cost");
+
+  Measure(base::BindOnce([](size_t num_iterations) {
+            base::ThreadTicks now;
+            for (size_t i = 0; i < num_iterations; ++i) {
+              now = base::ThreadTicks::Now();
+            }
+          }),
+          num_iterations, "Measure thread time measurement cost");
+
+  Measure(
+      base::BindOnce(
+          [](MainThreadMetricsHelper* metrics_helper,
+             FrameSchedulerForTest* frame_scheduler, size_t num_iterations) {
+            base::sequence_manager::TaskQueue::Task task(
+                base::sequence_manager::TaskQueue::PostedTask(
+                    base::OnceClosure(), FROM_HERE),
+                base::TimeTicks());
+
+            base::TimeTicks now =
+                base::TimeTicks() + base::TimeDelta::FromSeconds(1);
+            base::TimeDelta delta = base::TimeDelta::FromMilliseconds(10);
+
+            scoped_refptr<MainThreadTaskQueue> queue =
+                frame_scheduler->GetTaskQueueForTesting();
+
+            for (size_t i = 0; i < num_iterations; ++i) {
+              metrics_helper->RecordTaskMetrics(queue.get(), task, now,
+                                                now + delta, base::nullopt);
+              now += delta;
+            }
+          },
+          base::Unretained(metrics_helper_.get()),
+          base::Unretained(frame_scheduler_.get())),
+      num_iterations, "Measure per-task metric cost");
+
+  Measure(
+      base::BindOnce(
+          [](scoped_refptr<MainThreadTaskQueue> queue, size_t num_iterations) {
+            queue->PostTask(FROM_HERE, base::BindOnce(&RunChainedTask, queue,
+                                                      num_iterations));
+            base::RunLoop().RunUntilIdle();
+          },
+          frame_scheduler_->GetTaskQueueForTesting()),
+      num_iterations, "Measure a total cost of running a task");
+
+  DCHECK(false);
+}
+
+}  // namespace scheduler
+}  // namespace blink