528273 - Remove jitter and ringing in setTimeout/setInterval

Status: NEW

(Core :: DOM: Core & HTML, defect, P3)

Description

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

setTimeout and setInterval exibit significant jitter, and more worryingly, some extreme ringing.  We should try to remove both of these effects.  Two benchmarks are attached, one for setTimeout and one for setInterval, both using an explicit 10ms interval.

Comment 1

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

Attachment: setTimeout test

Comment 2

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

Attachment: setInterval test

Comment 3

[Boris Zbarsky [:bzbarsky]]

Fundamentally, I think it's the timer thread's attempts at correction that screw us over here....

Comment 4

[Ben Kelly [:bkelly, not reviewing]]

FWIW, we seem to be pretty good on the two test cases here on both linux/mac.  We only jitter by ~1ms.

On windows, though, we seem to be bimodal between 10ms (the target) and 15ms.  Its unclear to me why we vary by 5ms instead of 1ms on windows.  I assume because of some platform specific nsTimer effect or rounding through the TimeoutExecutor.

Comment 5

[Ben Kelly [:bkelly, not reviewing]]

Andreas, Nathan, see comment 4.

Comment 6

[Marion Daly [:mdaly]]

Overholt: is this still relevant ?