Reduce the number of delayed tasks on chromium run loop

Reduce the number of delayed tasks on chromium run loop

Previously if there were N distinct delayed times for dealyed tasks
posted to the scheduler, there would be N delayed tasks posted on the
chromium run loop.  We only really need to post timers for the next
delayed task.  This patch implements that. Caveat: because it's not
possible to cancel tasks posted to the chromium runloop, we will still
have more than one task outstanding if delayed tasks get posted in
reverse order.

BUG=510398, 546953
Committed: https://crrev.com/a0a01db6cee762f21b59648a6a4e0c2017b2f934
Cr-Commit-Position: refs/heads/master@{#361086}

[alex clarke (OOO till 29th), 2015-11-20 11:44:48]

Description was changed from

==========
Reduce the number of delayed tasks on chromium run loop

Previously if there were N distinct delayed time for dealyed tasks there
would be N delayed tasks posted on the chromium run loop.  We only
really need to post timers for the next delayed task.  This patch
implements that, although because it's not possible to cancel tasks
posted to the chromoum runloop, we will still have more than one
task outstanding if a delayed task that needs to get run sooner than
the current next delayed task is posted.

BUG=510398, 546953
==========

to

==========
Reduce the number of delayed tasks on chromium run loop

Previously if there were N distinct delayed time for dealyed tasks there
would be N delayed tasks posted on the chromium run loop.  We only
really need to post timers for the next delayed task.  This patch
implements that, although because it's not possible to cancel tasks
posted to the chromoum runloop, we will still have more than one
task outstanding if a delayed task that needs to get run sooner than
the current next delayed task is posted.

BUG=510398, 546953
==========

[alex clarke (OOO till 29th), 2015-11-20 11:44:48]

alexclarke@chromium.org changed reviewers:
+ skyostil@chromium.org

[alex clarke (OOO till 29th), 2015-11-20 11:50:04]

Description was changed from

==========
Reduce the number of delayed tasks on chromium run loop

Previously if there were N distinct delayed time for dealyed tasks there
would be N delayed tasks posted on the chromium run loop.  We only
really need to post timers for the next delayed task.  This patch
implements that, although because it's not possible to cancel tasks
posted to the chromoum runloop, we will still have more than one
task outstanding if a delayed task that needs to get run sooner than
the current next delayed task is posted.

BUG=510398, 546953
==========

to

==========
Reduce the number of delayed tasks on chromium run loop

Previously if there were N distinct delayed times for dealyed tasks
there would be N delayed tasks posted on the chromium run loop.  We
only really need to post timers for the next delayed task.  This patch
implements that. Caveat: because it's not possible to cancel tasks
posted to the chromium runloop, we will still have more than one
task outstanding if delayed tasks get posted in reverse
order.

BUG=510398, 546953
==========

[alex clarke (OOO till 29th), 2015-11-20 11:50:15]

Description was changed from

==========
Reduce the number of delayed tasks on chromium run loop

Previously if there were N distinct delayed times for dealyed tasks
there would be N delayed tasks posted on the chromium run loop.  We
only really need to post timers for the next delayed task.  This patch
implements that. Caveat: because it's not possible to cancel tasks
posted to the chromium runloop, we will still have more than one
task outstanding if delayed tasks get posted in reverse
order.

BUG=510398, 546953
==========

to

==========
Reduce the number of delayed tasks on chromium run loop

Previously if there were N distinct delayed times for dealyed tasks
there would be N delayed tasks posted on the chromium run loop.  We
only really need to post timers for the next delayed task.  This patch
implements that. Caveat: because it's not possible to cancel tasks
posted to the chromium runloop, we will still have more than one
task outstanding if delayed tasks get posted in reverse order.

BUG=510398, 546953
==========

[alex clarke (OOO till 29th), 2015-11-20 11:51:12]

Description was changed from

==========
Reduce the number of delayed tasks on chromium run loop

Previously if there were N distinct delayed times for dealyed tasks
there would be N delayed tasks posted on the chromium run loop.  We
only really need to post timers for the next delayed task.  This patch
implements that. Caveat: because it's not possible to cancel tasks
posted to the chromium runloop, we will still have more than one
task outstanding if delayed tasks get posted in reverse order.

BUG=510398, 546953
==========

to

==========
Reduce the number of delayed tasks on chromium run loop

Previously if there were N distinct delayed times for dealyed tasks
posted to the scheduler, there would be N delayed tasks posted on the
chromium run loop.  We only really need to post timers for the next
delayed task.  This patch implements that. Caveat: because it's not
possible to cancel tasks posted to the chromium runloop, we will still
have more than one task outstanding if delayed tasks get posted in 
reverse order.

BUG=510398, 546953
==========

[alex clarke (OOO till 29th), 2015-11-20 12:05:45]

The CQ bit was checked by alexclarke@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-11-20 12:05:58]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1468443002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1468443002/20001

[commit-bot: I haz the power, 2015-11-20 12:32:50]

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

[commit-bot: I haz the power, 2015-11-20 12:32:50]

Dry run: Try jobs failed on following builders:
  linux_chromium_chromeos_rel_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[alex clarke (OOO till 29th), 2015-11-20 15:10:53]

The CQ bit was checked by alexclarke@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-11-20 15:11:14]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1468443002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1468443002/40001

[commit-bot: I haz the power, 2015-11-20 16:11:19]

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

[commit-bot: I haz the power, 2015-11-20 16:11:21]

Dry run: This issue passed the CQ dry run.

[Sami, 2015-11-20 17:58:53]

To summarize our discussion: Let's give registered TimeDomains access to the TQM
delegate and the DoWork closure so that VirtualTimeDomain::AdvanceTime can just
post DoWork() and we can avoid special casing what happens in
EnqueueReadyDelayedTasks.

[alex clarke (OOO till 29th), 2015-11-20 18:20:29]

On 2015/11/20 17:58:53, Sami wrote:
> To summarize our discussion: Let's give registered TimeDomains access to the
TQM
> delegate and the DoWork closure so that VirtualTimeDomain::AdvanceTime can
just
> post DoWork() and we can avoid special casing what happens in
> EnqueueReadyDelayedTasks.

I've done that. PTAL

[alex clarke (OOO till 29th), 2015-11-20 18:20:34]

The CQ bit was checked by alexclarke@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-11-20 18:21:30]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1468443002/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1468443002/60001

[alex clarke (OOO till 29th), 2015-11-20 18:22:07]

The CQ bit was checked by alexclarke@chromium.org to run a CQ dry run

[alex clarke (OOO till 29th), 2015-11-20 18:23:01]

The CQ bit was checked by alexclarke@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-11-20 18:23:23]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1468443002/80001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1468443002/80001

[Sami, 2015-11-20 19:20:00]

lgtm % weakpointerification.

https://codereview.chromium.org/1468443002/diff/100001/components/scheduler/b...
File components/scheduler/base/real_time_domain.cc (right):

https://codereview.chromium.org/1468443002/diff/100001/components/scheduler/b...
components/scheduler/base/real_time_domain.cc:55:
base::Bind(&RealTimeDomain::WrappedDoWorkTask, this, run_time),
I think this might need to be a weak pointer to guard against the domain getting
destroyed before the timeout expires.

[commit-bot: I haz the power, 2015-11-20 19:46:38]

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

[commit-bot: I haz the power, 2015-11-20 19:46:38]

Dry run: This issue passed the CQ dry run.

[alex clarke (OOO till 29th), 2015-11-23 10:11:51]

https://codereview.chromium.org/1468443002/diff/100001/components/scheduler/b...
File components/scheduler/base/real_time_domain.cc (right):

https://codereview.chromium.org/1468443002/diff/100001/components/scheduler/b...
components/scheduler/base/real_time_domain.cc:55:
base::Bind(&RealTimeDomain::WrappedDoWorkTask, this, run_time),
On 2015/11/20 19:20:00, Sami wrote:
> I think this might need to be a weak pointer to guard against the domain
getting
> destroyed before the timeout expires.

Done.

[alex clarke (OOO till 29th), 2015-11-23 10:11:57]

The CQ bit was checked by alexclarke@chromium.org

[alex clarke (OOO till 29th), 2015-11-23 10:11:57]

The patchset sent to the CQ was uploaded after l-g-t-m from
skyostil@chromium.org
Link to the patchset: https://codereview.chromium.org/1468443002/#ps120001
(title: "Weak pointer")

[commit-bot: I haz the power, 2015-11-23 10:12:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1468443002/120001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1468443002/120001

[commit-bot: I haz the power, 2015-11-23 11:10:35]

Committed patchset #7 (id:120001)

[commit-bot: I haz the power, 2015-11-23 11:11:30]

Patchset 7 (id:??) landed as
https://crrev.com/a0a01db6cee762f21b59648a6a4e0c2017b2f934
Cr-Commit-Position: refs/heads/master@{#361086}