1505070 - Use un-fuzzed timestamps for engine telemetry

Status: RESOLVED FIXED

(Core :: JavaScript Engine, enhancement)

Description

[Jon Coppeard (:jonco)]

When fuzzyfox (bug 1432429) is enabled, TimeStamp::Now() will return a 'fuzzed' timestamp.  We currently use this to calculating telemetry information for the GC and in a couple of other places.  We should use un-fuzzed timestamps for this as these will be more accurate.

I'm pretty sure we can fix this by making ReallyNow() use TimeStamp::NowUnfuzzed() instead.

Comment 1

[Tom Ritter [:tjr]]

Attachment: Bug 1505070 - Use un-fuzzed timestamps for JS Engine telemetry r?jonco

https://treeherder.mozilla.org/#/jobs?repo=try&revision=ce0255cd9823d6d844c0d55490a94157df39e4dd

Note that fuzyfox pauses the main thread (not workers yet, see Bug 1484300) so while this will report more accurate timestamps, the data will be different (worse) for fuzzyfox users. This is intentional, and we are able to separate out fuzzyfox users from telemetry when this is needed. (Right now we only have 2 users reporting telemetry.)

Comment 2

[Jon Coppeard (:jonco)]

Comment on attachment 9023048 [details] [diff] [review]
Bug 1505070 - Use un-fuzzed timestamps for JS Engine telemetry r?jonco

Review of attachment 9023048 [details] [diff] [review]:
-----------------------------------------------------------------

Great, thanks for taking this.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/80fe34783bfc
Use un-fuzzed timestamps for JS Engine telemetry r=jonco

Comment 4

[Arthur Iakab [arthur_iakab]]

https://hg.mozilla.org/mozilla-central/rev/80fe34783bfc