scheduler: Trace queue size at post time

content/renderer/scheduler/task_queue_manager.cc

Index: content/renderer/scheduler/task_queue_manager.cc
diff --git a/content/renderer/scheduler/task_queue_manager.cc b/content/renderer/scheduler/task_queue_manager.cc
index 112a37ca33c120b61319a12d587106335badfaf0..0c3fcf58a4f91350f8f968b8e98fea23c1848eb9 100644
--- a/content/renderer/scheduler/task_queue_manager.cc
+++ b/content/renderer/scheduler/task_queue_manager.cc
@@ -69,7 +69,7 @@ class TaskQueue : public base::SingleThreadTaskRunner {
   void PumpQueueLocked();
   void EnqueueTaskLocked(const base::PendingTask& pending_task);
 
-  void TraceWorkQueueSize() const;
+  void TraceQueueSize(bool is_locked) const;
   static void QueueAsValueInto(const base::TaskQueue& queue,
                                base::trace_event::TracedValue* state);
   static void TaskAsValueInto(const base::PendingTask& task,
@@ -155,7 +155,7 @@ bool TaskQueue::UpdateWorkQueue(base::TimeTicks* next_pending_delayed_task) {
     if (!auto_pump_ || incoming_queue_.empty())
       return false;
     work_queue_.Swap(&incoming_queue_);
-    TraceWorkQueueSize();
+    TraceQueueSize(true);
     return true;
   }
 }
@@ -163,15 +163,24 @@ bool TaskQueue::UpdateWorkQueue(base::TimeTicks* next_pending_delayed_task) {
 base::PendingTask TaskQueue::TakeTaskFromWorkQueue() {
   base::PendingTask pending_task = work_queue_.front();
   work_queue_.pop();
-  TraceWorkQueueSize();
+  TraceQueueSize(false);
   return pending_task;
 }
 
-void TaskQueue::TraceWorkQueueSize() const {
-  if (!name_)
+void TaskQueue::TraceQueueSize(bool is_locked) const {
+  bool is_tracing;
+  TRACE_EVENT_CATEGORY_GROUP_ENABLED(
+      TRACE_DISABLED_BY_DEFAULT("renderer.scheduler"), &is_tracing);
+  if (!is_tracing || !name_)
     return;
+  if (!is_locked)

[alex clarke (OOO till 29th), 2015/02/25 12:37:51]

Did you consider using lock_.Try() here?

[alex clarke (OOO till 29th), 2015/02/25 12:38:51]

Ah you can't do that on the same thread.

+    lock_.Acquire();
+  else
+    lock_.AssertAcquired();
   TRACE_COUNTER1(TRACE_DISABLED_BY_DEFAULT("renderer.scheduler"), name_,
-                 work_queue_.size());
+                 incoming_queue_.size() + work_queue_.size());
+  if (!is_locked)
+    lock_.Release();
 }
 
 void TaskQueue::EnqueueTask(const base::PendingTask& pending_task) {
@@ -197,6 +206,7 @@ void TaskQueue::EnqueueTaskLocked(const base::PendingTask& pending_task) {
     // before getting here.
     incoming_queue_.back().delayed_run_time = base::TimeTicks();
   }
+  TraceQueueSize(true);
 }
 
 void TaskQueue::SetAutoPump(bool auto_pump) {