base: Test the cost of adding observers on message loops.

base: Test the cost of adding observers on message loops.

Adds about ~5us per task on Nexus 4.

BUG=None

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=266155

[epenner, 2014-04-24 02:01:20]

Ptal. Not as big of a difference as I thought, but it's good to know this path
exits.

[Nico, 2014-04-24 02:52:19]

lgtm

https://codereview.chromium.org/254423003/diff/20001/base/threading/thread_pe...
File base/threading/thread_perftest.cc (right):

https://codereview.chromium.org/254423003/diff/20001/base/threading/thread_pe...
base/threading/thread_perftest.cc:156: MessageLoopObserver
message_loop_observer;
Does this have to be a global? Can you make this a member of
TaskObserverPerfTest instead?

[epenner, 2014-04-24 03:14:35]

https://codereview.chromium.org/254423003/diff/20001/base/threading/thread_pe...
File base/threading/thread_perftest.cc (right):

https://codereview.chromium.org/254423003/diff/20001/base/threading/thread_pe...
base/threading/thread_perftest.cc:156: MessageLoopObserver
message_loop_observer;
On 2014/04/24 02:52:20, Nico wrote:
> Does this have to be a global? Can you make this a member of
> TaskObserverPerfTest instead?

Good point. I wasn't thinking about it since it's a test. But best to have no
globals indeed. Moved it to the class.

[epenner, 2014-04-24 03:14:41]

The CQ bit was checked by epenner@chromium.org

[commit-bot: I haz the power, 2014-04-24 03:15:10]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/epenner@chromium.org/254423003/20001

[commit-bot: I haz the power, 2014-04-24 03:48:28]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-04-24 03:48:28]

Try jobs failed on following builders:
  tryserver.chromium on win_chromium_rel

[epenner, 2014-04-24 18:58:14]

The CQ bit was checked by epenner@chromium.org

[commit-bot: I haz the power, 2014-04-24 21:08:57]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/epenner@chromium.org/254423003/20001

[commit-bot: I haz the power, 2014-04-24 22:58:54]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-04-24 22:58:55]

Try jobs failed on following builders:
  tryserver.chromium on win_chromium_rel

[epennerAtGoogle, 2014-04-25 02:41:34]

The CQ bit was checked by epenner@google.com

[commit-bot: I haz the power, 2014-04-25 02:45:55]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/epenner@chromium.org/254423003/20001

[commit-bot: I haz the power, 2014-04-25 08:28:26]

Change committed as 266155