1548355 - Tweak sLastCCEndTime handling to be able to check two tasks within < 1ms

Status: RESOLVED FIXED

(Core :: DOM: Core & HTML, enhancement)

Description

[Olli Pettay [:smaug][[e-mail]]]

Attachment: sLastCCEndTime_tweak.diff

This is similar to bug 1548146.
I was wondering why I was getting CCs too close to each others after browsing away from youtube.
This would explain why 5% of CYCLE_COLLECTOR_TIME_BETWEEN is 0.

I guess this isn't quite as safe as bug 1548146.

(still away from my main machine, so moz-phab doesn't work. Misusing data-review)

Comment 1

[Andrew McCreight [:mccr8]]

Comment on attachment 9061985 [details] [diff] [review]
sLastCCEndTime_tweak.diff

Review of attachment 9061985 [details] [diff] [review]:
-----------------------------------------------------------------

Should TimeUntilNow just return 0 if the argument is null?

Comment 2

[Olli Pettay [:smaug][[e-mail]]]

That is the issue that it returns 0. One can't differentiate null timestamp and < 1ms period.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/2aa89383ecb5
Tweak sLastCCEndTime handling to be able to check two tasks within < 1ms, r=mccr8

Comment 4

[Raul Gurzau (:RaulG)]

https://hg.mozilla.org/mozilla-central/rev/2aa89383ecb5

Comment 5

[Andrew Creskey [:acreskey]]

FYI, this change lead to ~16% improvement on the raptor pageload score for reddit:
https://treeherder.mozilla.org/perf.html#/compare?originalProject=try&originalRevision=a2afd1fb84809a04ca02d1305afe376fc42bf523&newProject=try&newRevision=b5047a911aa95f55fcf82d7c605f36d760327a80&framework=10

Including a ~35% improvement on loadtime:
https://treeherder.mozilla.org/perf.html#/comparesubtest?originalProject=try&newProject=try&newRevision=b5047a911aa95f55fcf82d7c605f36d760327a80&originalSignature=1907420&newSignature=1907420&framework=10&originalRevision=a2afd1fb84809a04ca02d1305afe376fc42bf523

Comment 6

[Olli Pettay [:smaug][[e-mail]]]

Which hints that this pushed some GC out from load time, so that bug 1543806 wouldn't get kicked in.

Comment 7

[Florin Strugariu [:Bebe]]

== Change summary for alert #20778 (as of Fri, 03 May 2019 02:53:26 GMT) ==

Improvements:

43% raptor-tp6-reddit-firefox loadtime windows10-64-shippable opt 3,928.25 -> 2,240.46
22% raptor-tp6-reddit-firefox windows10-64-shippable opt 784.05 -> 608.00
16% raptor-tp6-reddit-firefox fcp windows10-64-shippable opt 348.56 -> 294.50
11% raptor-tp6-reddit-firefox loadtime linux64-shippable opt 2,080.54 -> 1,846.17
9% raptor-tp6-reddit-firefox linux64-shippable opt 566.06 -> 513.09
9% raptor-tp6-youtube-firefox loadtime linux64-shippable-qr opt 605.94 -> 553.38
9% raptor-tp6-reddit-firefox fcp linux64-shippable opt 277.15 -> 253.33
5% raptor-tp6-youtube-firefox linux64-shippable-qr opt 308.96 -> 293.23

For up to date results, see: https://treeherder.mozilla.org/perf.html#/alerts?id=20778