content: Add RendererScheduler.

content/renderer/scheduler/renderer_scheduler_impl.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 "content/renderer/scheduler/renderer_scheduler_impl.h"
+
+#include "base/bind.h"
+#include "cc/output/begin_frame_args.h"
+#include "content/renderer/scheduler/renderer_task_queue_selector.h"
+#include "ui/gfx/frame_time.h"
+
+namespace content {
+
+RendererSchedulerImpl::RendererSchedulerImpl(
+    scoped_refptr<base::SingleThreadTaskRunner> main_task_runner)
+    : renderer_task_queue_selector_(new RendererTaskQueueSelector()),
+      task_queue_manager_(
+          new TaskQueueManager(TASK_QUEUE_COUNT,
+                               main_task_runner,
+                               renderer_task_queue_selector_.get())),
+      control_task_runner_(
+          task_queue_manager_->TaskRunnerForQueue(CONTROL_TASK_QUEUE)),
+      default_task_runner_(
+          task_queue_manager_->TaskRunnerForQueue(DEFAULT_TASK_QUEUE)),
+      compositor_task_runner_(
+          task_queue_manager_->TaskRunnerForQueue(COMPOSITOR_TASK_QUEUE)),
+      current_policy_(NORMAL_PRIORITY_POLICY),
+      policy_may_need_update_(&incoming_signals_lock_),
+      weak_factory_(this) {
+  weak_renderer_scheduler_ptr_ = weak_factory_.GetWeakPtr();
+  idle_task_runner_ = make_scoped_refptr(new SingleThreadIdleTaskRunner(
+      task_queue_manager_->TaskRunnerForQueue(IDLE_TASK_QUEUE),
+      weak_factory_.GetWeakPtr()));
+  renderer_task_queue_selector_->SetQueuePriority(
+      CONTROL_TASK_QUEUE, RendererTaskQueueSelector::CONTROL_PRIORITY);
+  renderer_task_queue_selector_->DisableQueue(IDLE_TASK_QUEUE);
+  task_queue_manager_->SetAutoPump(IDLE_TASK_QUEUE, false);
+}
+
+RendererSchedulerImpl::~RendererSchedulerImpl() {
+}
+
+void RendererSchedulerImpl::Shutdown() {
+  task_queue_manager_.reset();
+}
+
+scoped_refptr<base::SingleThreadTaskRunner>
+RendererSchedulerImpl::DefaultTaskRunner() {
+  return default_task_runner_;
+}
+
+scoped_refptr<base::SingleThreadTaskRunner>
+RendererSchedulerImpl::CompositorTaskRunner() {
+  return compositor_task_runner_;
+}
+
+scoped_refptr<SingleThreadIdleTaskRunner>
+RendererSchedulerImpl::IdleTaskRunner() {
+  return idle_task_runner_;
+}
+
+void RendererSchedulerImpl::WillBeginFrame(const cc::BeginFrameArgs& args) {
+  main_thread_checker_.CalledOnValidThread();
+  if (!task_queue_manager_)
+    return;
+
+  EndIdlePeriod();
+  estimated_next_frame_begin_ = args.frame_time + args.interval;
+}
+
+void RendererSchedulerImpl::DidCommitFrameToCompositor() {
+  main_thread_checker_.CalledOnValidThread();
+  if (!task_queue_manager_)
+    return;
+
+  base::TimeTicks now(Now());
+  if (now < estimated_next_frame_begin_) {
+    StartIdlePeriod();
+    control_task_runner_->PostDelayedTask(
+        FROM_HERE,
+        base::Bind(&RendererSchedulerImpl::EndIdlePeriod,
+                   weak_renderer_scheduler_ptr_),

[jdduke (slow), 2014/11/03 21:33:48]

See below (wondering if caching the closure provides any benefit here).

[rmcilroy, 2014/11/04 02:22:20]

Done.

+        estimated_next_frame_begin_ - now);
+  }
+}
+
+void RendererSchedulerImpl::DidReceiveInputEvent() {
+  // TODO(rmcilroy): Decide whether only a subset of input events should trigger
+  // compositor priority policy - http://crbug.com/429814.
+  base::AutoLock lock(incoming_signals_lock_);
+  if (last_input_time_.is_null()) {
+    // Update scheduler policy if should start a new compositor policy mode.
+    policy_may_need_update_.SetLocked(true);
+    PostUpdatePolicyOnControlRunner(base::TimeDelta());
+  }
+  last_input_time_ = Now();
+}
+
+bool RendererSchedulerImpl::ShouldYieldForHighPriorityWork() {
+  main_thread_checker_.CalledOnValidThread();
+  if (!task_queue_manager_)
+    return false;
+
+  return SchedulerPolicy() == COMPOSITOR_PRIORITY_POLICY &&
+         !task_queue_manager_->IsQueueEmpty(COMPOSITOR_TASK_QUEUE);
+}
+
+base::TimeTicks RendererSchedulerImpl::CurrentIdleTaskDeadline() const {
+  main_thread_checker_.CalledOnValidThread();
+  return estimated_next_frame_begin_;
+}
+
+RendererSchedulerImpl::Policy RendererSchedulerImpl::SchedulerPolicy() {
+  main_thread_checker_.CalledOnValidThread();
+  if (policy_may_need_update_.IsSet()) {
+    UpdatePolicy();
+  }
+  return current_policy_;
+}
+
+void RendererSchedulerImpl::PostUpdatePolicyOnControlRunner(
+    base::TimeDelta delay) {
+  base::Closure closure = base::Bind(&RendererSchedulerImpl::UpdatePolicy,

[jdduke (slow), 2014/11/03 21:33:48]

It looks like |weak_renderer_scheduler_ptr_| never changes. I don't know enough
about the details of our Callback implementation, but would we benefit from
caching the closure and not regenerating for every update (i.e., can we avoid a
heap alloc here?)?

[rmcilroy, 2014/11/04 02:22:20]

Yes, it looks like caching the closure would avoid at least one heap alloc here
- done.

+                                     weak_renderer_scheduler_ptr_);
+  control_task_runner_->PostDelayedTask(FROM_HERE, closure, delay);
+}
+
+void RendererSchedulerImpl::UpdatePolicy() {
+  main_thread_checker_.CalledOnValidThread();
+  if (!task_queue_manager_)
+    return;
+
+  base::AutoLock lock(incoming_signals_lock_);
+  policy_may_need_update_.SetLocked(false);
+
+  Policy new_policy = NORMAL_PRIORITY_POLICY;
+  if (!last_input_time_.is_null()) {
+    base::TimeDelta compositor_priority_duration =
+        base::TimeDelta::FromMilliseconds(kCompositorPriorityAfterTouchMillis);
+    base::TimeTicks compositor_priority_end(last_input_time_ +
+                                            compositor_priority_duration);
+    base::TimeTicks now(Now());
+    if (compositor_priority_end > now) {
+      PostUpdatePolicyOnControlRunner(compositor_priority_end - now);
+      new_policy = COMPOSITOR_PRIORITY_POLICY;
+    } else {
+      // Null out last_input_time_ to ensure DidReceiveInputEvent will post an
+      // UpdatePolicy task when it's next called.
+      last_input_time_ = base::TimeTicks();
+    }
+  }
+
+  if (new_policy == current_policy_) {

[jdduke (slow), 2014/11/03 21:33:48]

Nit: No braces necessary.

[rmcilroy, 2014/11/04 02:22:20]

Done.

+    return;
+  }
+
+  switch (new_policy) {
+    case COMPOSITOR_PRIORITY_POLICY:
+      renderer_task_queue_selector_->SetQueuePriority(
+          COMPOSITOR_TASK_QUEUE, RendererTaskQueueSelector::HIGH_PRIORITY);
+      break;
+    case NORMAL_PRIORITY_POLICY:
+      renderer_task_queue_selector_->SetQueuePriority(
+          COMPOSITOR_TASK_QUEUE, RendererTaskQueueSelector::NORMAL_PRIORITY);
+      break;
+  }
+  current_policy_ = new_policy;
+}
+
+void RendererSchedulerImpl::StartIdlePeriod() {
+  renderer_task_queue_selector_->EnableQueue(
+      IDLE_TASK_QUEUE, RendererTaskQueueSelector::BEST_EFFORT_PRIORITY);
+  task_queue_manager_->PumpQueue(IDLE_TASK_QUEUE);
+}
+
+void RendererSchedulerImpl::EndIdlePeriod() {
+  renderer_task_queue_selector_->DisableQueue(IDLE_TASK_QUEUE);
+}
+
+base::TimeTicks RendererSchedulerImpl::Now() const {
+  return gfx::FrameTime::Now();
+}
+
+PolicyNeedsUpdateFlag::PolicyNeedsUpdateFlag(base::Lock* write_lock_)
+    : flag_(false), write_lock_(write_lock_) {
+}
+
+PolicyNeedsUpdateFlag::~PolicyNeedsUpdateFlag() {
+}
+
+void PolicyNeedsUpdateFlag::SetLocked(bool value) {
+  write_lock_->AssertAcquired();
+  base::subtle::Release_Store(&flag_, value);
+}
+
+bool PolicyNeedsUpdateFlag::IsSet() const {
+  thread_checker_.CalledOnValidThread();
+  return base::subtle::Acquire_Load(&flag_);
+}
+}  // namespace content