scheduler: Only prioritize rAF if it is fast

scheduler: Only prioritize rAF if it is fast

To avoid starving other tasks, only prioritize main thread compositing (i.e.,
requestAnimationFrame) if there is more than 80% idle time left in a frame. This can
reduce animation frame rate on sites which can't keep up with the display refresh
rate, but will ensure other tasks (e.g., postMessage) aren't starved as a
side-effect.

BUG=600385
Committed: https://crrev.com/6f3d26fe1385dc74f22bf2cf6bddc6830dd00d6c
Cr-Commit-Position: refs/heads/master@{#391221}

[alex clarke (OOO till 29th), 2016-05-03 09:47:00]

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

[alex clarke (OOO till 29th), 2016-05-03 09:47:01]

https://codereview.chromium.org/1914373004/diff/1/components/scheduler/render...
File components/scheduler/renderer/renderer_scheduler_impl.cc (right):

https://codereview.chromium.org/1914373004/diff/1/components/scheduler/render...
components/scheduler/renderer/renderer_scheduler_impl.cc:687:
base::TimeDelta::FromSeconds(0);
As discussed off line I'm wondering if this might be a fairer computation:

double min_idle_ratio = 0.2;  // needs a better name
bool main_thread_compositing_is_fast =
    MainThreadOnly().idle_time_estimator.GetExpectedIdleDuration(
         MainThreadOnly().compositor_frame_interval) >
    MainThreadOnly().compositor_frame_interval * min_idle_ratio;

[Sami, 2016-05-03 12:49:06]

Description was changed from

==========
scheduler: Only prioritize rAF if it is fast

BUG=600385
==========

to

==========
scheduler: Only prioritize rAF if it is fast

To avoid starving other tasks, only prioritize main thread compositing (i.e., 
requestAnimationFrame) if there is more than 80% idle time left in a frame. This
can
reduce animation frame rate on sites which can't keep up with the display
refresh
rate, but will ensure other tasks (e.g., postMessage) aren't starved as a
side-effect.

BUG=600385
==========

[Sami, 2016-05-03 12:50:00]

https://codereview.chromium.org/1914373004/diff/1/components/scheduler/render...
File components/scheduler/renderer/renderer_scheduler_impl.cc (right):

https://codereview.chromium.org/1914373004/diff/1/components/scheduler/render...
components/scheduler/renderer/renderer_scheduler_impl.cc:687:
base::TimeDelta::FromSeconds(0);
On 2016/05/03 09:47:01, alex clarke wrote:
> As discussed off line I'm wondering if this might be a fairer computation:
> 
> double min_idle_ratio = 0.2;  // needs a better name
> bool main_thread_compositing_is_fast =
>     MainThreadOnly().idle_time_estimator.GetExpectedIdleDuration(
>          MainThreadOnly().compositor_frame_interval) >
>     MainThreadOnly().compositor_frame_interval * min_idle_ratio;

Yep, that's probably safer. Done.

[Sami, 2016-05-03 12:50:23]

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

[commit-bot: I haz the power, 2016-05-03 12:50:32]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1914373004/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1914373004/20001

[alex clarke (OOO till 29th), 2016-05-03 13:05:03]

lgtm

[Sami, 2016-05-03 13:12:28]

The CQ bit was unchecked by skyostil@chromium.org

[Sami, 2016-05-03 13:12:32]

The CQ bit was checked by skyostil@chromium.org

[commit-bot: I haz the power, 2016-05-03 13:12:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1914373004/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1914373004/20001

[commit-bot: I haz the power, 2016-05-03 13:40:52]

Description was changed from

==========
scheduler: Only prioritize rAF if it is fast

To avoid starving other tasks, only prioritize main thread compositing (i.e., 
requestAnimationFrame) if there is more than 80% idle time left in a frame. This
can
reduce animation frame rate on sites which can't keep up with the display
refresh
rate, but will ensure other tasks (e.g., postMessage) aren't starved as a
side-effect.

BUG=600385
==========

to

==========
scheduler: Only prioritize rAF if it is fast

To avoid starving other tasks, only prioritize main thread compositing (i.e., 
requestAnimationFrame) if there is more than 80% idle time left in a frame. This
can
reduce animation frame rate on sites which can't keep up with the display
refresh
rate, but will ensure other tasks (e.g., postMessage) aren't starved as a
side-effect.

BUG=600385
==========

[commit-bot: I haz the power, 2016-05-03 13:40:53]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-05-03 13:42:06]

Description was changed from

==========
scheduler: Only prioritize rAF if it is fast

To avoid starving other tasks, only prioritize main thread compositing (i.e., 
requestAnimationFrame) if there is more than 80% idle time left in a frame. This
can
reduce animation frame rate on sites which can't keep up with the display
refresh
rate, but will ensure other tasks (e.g., postMessage) aren't starved as a
side-effect.

BUG=600385
==========

to

==========
scheduler: Only prioritize rAF if it is fast

To avoid starving other tasks, only prioritize main thread compositing (i.e.,
requestAnimationFrame) if there is more than 80% idle time left in a frame. This
can
reduce animation frame rate on sites which can't keep up with the display
refresh
rate, but will ensure other tasks (e.g., postMessage) aren't starved as a
side-effect.

BUG=600385

Committed: https://crrev.com/6f3d26fe1385dc74f22bf2cf6bddc6830dd00d6c
Cr-Commit-Position: refs/heads/master@{#391221}
==========

[commit-bot: I haz the power, 2016-05-03 13:42:07]

Patchset 2 (id:??) landed as
https://crrev.com/6f3d26fe1385dc74f22bf2cf6bddc6830dd00d6c
Cr-Commit-Position: refs/heads/master@{#391221}