Add heap allocator usage to task profiler.

base/debug/task_annotator.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 "base/debug/task_annotator.h"
 
 #include "base/debug/activity_tracker.h"
 #include "base/debug/alias.h"
 #include "base/pending_task.h"
 #include "base/trace_event/trace_event.h"
@@ skipping 13 matching lines @@
   TRACE_EVENT_WITH_FLOW0(TRACE_DISABLED_BY_DEFAULT("toplevel.flow"),
                           queue_function,
                           TRACE_ID_MANGLE(GetTaskTraceID(pending_task)),
                           TRACE_EVENT_FLAG_FLOW_OUT);
 }
 
 void TaskAnnotator::RunTask(const char* queue_function,
                             const PendingTask& pending_task) {
   ScopedTaskRunActivity task_activity(pending_task);
 
+  base::debug::HeapUsageTracker heap_usage;

[Primiano Tucci (use gerrit), 2016/10/13 20:47:44]

btw  liked Scoped in the name, made it clear that heap_usage here is a scoped
thing.

[Sigurður Ásgeirsson, 2016/10/14 20:11:35]

Yeah, the problem is that the existing instrumentation collects exclusive
metrics (e.g. an inner measured thing does not contribute cost to the outer
measured thing).
A Scoped* thingy can't support that, as there will always be a gap from
Scoped*::ReadUsage to it passing out of scope, and that gap will be altogether
missing from the tally.

I could reinstate a Scoped* as a subclass of HeapUsageTracker, which only
supports inclusive measurement?

   tracked_objects::TaskStopwatch stopwatch;
   stopwatch.Start();
   tracked_objects::Duration queue_duration =
       stopwatch.StartTime() - pending_task.EffectiveTimePosted();
 
   TRACE_EVENT_WITH_FLOW1(TRACE_DISABLED_BY_DEFAULT("toplevel.flow"),
                           queue_function,
                           TRACE_ID_MANGLE(GetTaskTraceID(pending_task)),
                           TRACE_EVENT_FLAG_FLOW_IN,
                           "queue_duration",
                           queue_duration.InMilliseconds());
 
   // Before running the task, store the program counter where it was posted
   // and deliberately alias it to ensure it is on the stack if the task
   // crashes. Be careful not to assume that the variable itself will have the
   // expected value when displayed by the optimizer in an optimized build.
   // Look at a memory dump of the stack.
   const void* program_counter = pending_task.posted_from.program_counter();
   debug::Alias(&program_counter);
 
   pending_task.task.Run();
 
   stopwatch.Stop();
+

[Primiano Tucci (use gerrit), 2016/10/13 20:47:44]

silly question: what's the point of this scoped HeapUsageTracker if you never
collect the data at the end here?

[Sigurður Ásgeirsson, 2016/10/14 20:11:35]

Good catch - I've moved the HUT into the StopWatch, forgot to clean this up.

   tracked_objects::ThreadData::TallyRunOnNamedThreadIfTracking(
       pending_task, stopwatch);
 }
 
 uint64_t TaskAnnotator::GetTaskTraceID(const PendingTask& task) const {
   return (static_cast<uint64_t>(task.sequence_num) << 32) |
          ((static_cast<uint64_t>(reinterpret_cast<intptr_t>(this)) << 32) >>
           32);
 }
 
 }  // namespace debug
 }  // namespace base