835641 - Lots of UpdateDimensions calls being sent

Status: RESOLVED FIXED

(Core :: General, defect)

Description

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

I see flurries of 20 or so of these guys at a time while running with a logging patch applied.  This may be TabParent viewing inconsistent layout state.

All of the dimensions being sent must be the same, because there's no visual change.  Looks like a reflow triggered by the time changing or something.

We /should/ be smart enough to avoid reflow in the content process when the dimensions don't change, but that's a bit dangerous, and the overhead of sending the IPC's and waking up the various processes is not free either.

So we should cache dimensions in TabParent and skip forwarding these messages when possible.  We already cache part of the needed info.

Comment 1

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

Actually a lot of this is happening on a critical startup path.

Comment 2

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

Attachment: Don't SendUpdateDimensions() when they haven't changed

Going to confirm with my logging that this is actually having the intended effect ...

Comment 3

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

Comment on attachment 707393 [details] [diff] [review]
Don't SendUpdateDimensions() when they haven't changed

It do.

Comment 4

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

Guys, this bug could be causing numerous spurious wakeups in content processes in some cases, which might be dinging power numbers.

Comment 5

[Michael Vines [:m1] [:evilmachines]]

Vasanth, can you please get an eng build to the power guys w/ this patch to see if this helps with some of the wake-ups they are seeing?

Comment 6

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

(--> elsewhere)

Comment 7

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

https://hg.mozilla.org/integration/mozilla-inbound/rev/a24051aa1b46

Comment 8

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/a24051aa1b46

Comment 9

[[:fabrice] Fabrice Desré]

Chris, do we want to uplift that?

Comment 10

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

Comment on attachment 707393 [details] [diff] [review]
Don't SendUpdateDimensions() when they haven't changed

Yes.

This is a safe patch that removes unnecessary work from app startup and will prevent a lot of unnecessary process wakeups, which might be contributing to a power-usage problem.

Comment 11

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-b2g18/rev/51922f3008ff

Comment 12

[Michael Vines [:m1] [:evilmachines]]

Should we land this on v1.0.0 too?

Comment 13

[Alex Keybl [:akeybl]]

(In reply to Michael Vines [:m1] [:evilmachines] from comment #12)
> Should we land this on v1.0.0 too?

Is this a blocker for you? If so, then we'll tef+.

Comment 14

[Michael Vines [:m1] [:evilmachines]]

Yes please, based on comment 10

Comment 15

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-b2g18_v1_0_0/rev/4affefdc4336