Suspend more task queues for background renderers (experimental)

components/scheduler/renderer/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 "components/scheduler/renderer/renderer_scheduler_impl.h"
 
 #include "base/bind.h"
 #include "base/debug/stack_trace.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
@@ skipping 101 matching lines @@
       idle_time_estimator(compositor_task_runner,
                           time_source,
                           kShortIdlePeriodDurationSampleCount,
                           kShortIdlePeriodDurationPercentile),
       current_use_case(UseCase::NONE),
       timer_queue_suspend_count(0),
       navigation_task_expected_count(0),
       expensive_task_policy(ExpensiveTaskPolicy::RUN),
       renderer_hidden(false),
       renderer_backgrounded(false),
+      renderer_suspended(false),
       timer_queue_suspension_when_backgrounded_enabled(false),
       timer_queue_suspended_when_backgrounded(false),
       was_shutdown(false),
       loading_tasks_seem_expensive(false),
       timer_tasks_seem_expensive(false),
       touchstart_expected_soon(false),
       have_seen_a_begin_main_frame(false),
       have_reported_blocking_intervention_in_current_policy(false),
       have_reported_blocking_intervention_since_navigation(false),
       has_visible_render_widget_with_touch_handler(false),
@@ skipping 693 matching lines @@
       break;
   }
 
   MainThreadOnly().expensive_task_policy = expensive_task_policy;
 
   if (MainThreadOnly().timer_queue_suspend_count != 0 ||
       MainThreadOnly().timer_queue_suspended_when_backgrounded) {
     new_policy.timer_queue_policy.is_enabled = false;
   }
 
+  if (MainThreadOnly().renderer_suspended) {
+    new_policy.loading_queue_policy.is_enabled = false;
+    DCHECK(!new_policy.timer_queue_policy.is_enabled);
+  }
+
   // Tracing is done before the early out check, because it's quite possible we
   // will otherwise miss this information in traces.
   TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID(
       TRACE_DISABLED_BY_DEFAULT("renderer.scheduler"), "RendererScheduler",
       this, AsValueLocked(now));
   TRACE_COUNTER1(TRACE_DISABLED_BY_DEFAULT("renderer.scheduler"), "use_case",
                  use_case);
   TRACE_COUNTER1(TRACE_DISABLED_BY_DEFAULT("renderer.scheduler"),
                  "touchstart_expected_soon",
                  MainThreadOnly().touchstart_expected_soon);
@@ skipping 362 matching lines @@
          base::TimeDelta::FromMilliseconds(
              kIdlePeriodStarvationThresholdMillis);
 }
 
 void RendererSchedulerImpl::SuspendTimerQueueWhenBackgrounded() {
   DCHECK(MainThreadOnly().renderer_backgrounded);
   if (MainThreadOnly().timer_queue_suspended_when_backgrounded)
     return;
 
   MainThreadOnly().timer_queue_suspended_when_backgrounded = true;
+  MainThreadOnly().renderer_suspended = true;

[Sami, 2016/05/31 10:11:21]

I guess this is just for testing, but ultimately you'd want to do this in
RendererSchedulerImpl::SuspendRenderer().

[hajimehoshi, 2016/05/31 11:10:07]

Ah, this was my mistake: Setting this variable should be in SuspendRenderer as
you suggested. Done.

   ForceUpdatePolicy();
 }
 
 void RendererSchedulerImpl::ResumeTimerQueueWhenForegrounded() {
   DCHECK(!MainThreadOnly().renderer_backgrounded);
   if (!MainThreadOnly().timer_queue_suspended_when_backgrounded)
     return;
 
   MainThreadOnly().timer_queue_suspended_when_backgrounded = false;
+  MainThreadOnly().renderer_suspended = false;
   ForceUpdatePolicy();
 }
 
 void RendererSchedulerImpl::ResetForNavigationLocked() {
   helper_.CheckOnValidThread();
   any_thread_lock_.AssertAcquired();
   AnyThread().user_model.Reset(helper_.scheduler_tqm_delegate()->NowTicks());
   AnyThread().have_seen_touchstart = false;
   MainThreadOnly().loading_task_cost_estimator.Clear();
   MainThreadOnly().timer_task_cost_estimator.Clear();
@@ skipping 88 matching lines @@
     BroadcastConsoleWarning(
         "Blink deferred a task in order to make scrolling smoother. "
         "Your timer and network tasks should take less than 50ms to run "
         "to avoid this. Please see "
         "https://developers.google.com/web/tools/chrome-devtools/profile/evaluate-performance/rail"
         " and https://crbug.com/574343#c40 for more information.");
   }
 }
 
 }  // namespace scheduler