relnote: Use NotifyChangedPriority when updating alarms instead of canceling and reregistering. Gua…

relnote: Use UpdateImpl to cancel and set alarms. Guarded by quic_change_alarms_efficiently. Chromium doesn't support EpollAlarmQueue, this merge is to keep code consist. 

Merge internal change: 127449992

BUG=

[Zhongyi Shi, 2016-07-19 19:18:31]

zhongyi@chromium.org changed reviewers:
+ rch@chromium.org

[Zhongyi Shi, 2016-07-19 19:29:22]

+jdorfman

[Jeremy Dorfman, 2016-07-19 19:37:47]

On 2016/07/19 19:29:22, Zhongyi Shi wrote:
> +jdorfman

LGTM.

[Ryan Hamilton, 2016-07-19 21:13:38]

LGTM, but can you tweak the CL description (in the final CL too) 'since it does
not use NotifyChangedPriority.

https://codereview.chromium.org/2164483003/diff/1/net/quic/quic_alarm.cc
File net/quic/quic_alarm.cc (right):

https://codereview.chromium.org/2164483003/diff/1/net/quic/quic_alarm.cc#newc...
net/quic/quic_alarm.cc:78: SetImpl();
Hah! So in chromium UpdateImpl is basically Cancel() / Set(new_deadline)?

[Zhongyi Shi, 2016-07-19 22:33:54]

Description was changed from

==========
relnote: Use NotifyChangedPriority when updating alarms instead of canceling and
reregistering. Guarded by quic_change_alarms_efficiently.

The current approach of calling Cancel() and Set() when updating alarms
causes worst-case alarm churn in the priority queue. The faster approach is to
use NotifyChangedPriority directly.

Merge internal change: 127449992

BUG=
==========

to

==========
relnote: Use UpdateImpl to cancel and set alarms. Guarded by
quic_change_alarms_efficiently. Chromium doesn't support EpollAlarmQueue, this
merge is to keep code consist. 

Merge internal change: 127449992

BUG=
==========

[Zhongyi Shi, 2016-07-19 22:34:12]

On 2016/07/19 21:13:38, Ryan Hamilton wrote:
> LGTM, but can you tweak the CL description (in the final CL too) 'since it
does
> not use NotifyChangedPriority.
> 
> https://codereview.chromium.org/2164483003/diff/1/net/quic/quic_alarm.cc
> File net/quic/quic_alarm.cc (right):
> 
>
https://codereview.chromium.org/2164483003/diff/1/net/quic/quic_alarm.cc#newc...
> net/quic/quic_alarm.cc:78: SetImpl();
> Hah! So in chromium UpdateImpl is basically Cancel() / Set(new_deadline)?

Done.