Improve GC telemetry

RESOLVED FIXED in mozilla17

Status

()

Core
JavaScript Engine
RESOLVED FIXED
5 years ago
5 years ago

People

(Reporter: billm, Assigned: billm)

Tracking

unspecified
mozilla17
Points:
---

Firefox Tracking Flags

(Not tracked)

Details

Attachments

(1 attachment)

(Assignee)

Description

5 years ago
Created attachment 651010 [details] [diff] [review]
patch

This fixes the problem where GC_MS records the total time between the start and the end of the GC. I considered using a different histogram for this, but since the old one is totally useless, I think we should just replace it.

It also adds a max pause field, which is a little more useful than the GC_SLICE_MS histogram, which records the time of every slice, and so tends to be somewhat optimistic.

I also had it record the time for root marking and gray marking. I don't have a good idea of how long these phases are taking in the wild, so it would be good to get some data on this.
Attachment #651010 - Flags: review?(continuation)
Comment on attachment 651010 [details] [diff] [review]
patch

Review of attachment 651010 [details] [diff] [review]:
-----------------------------------------------------------------

Nice!

::: toolkit/components/telemetry/TelemetryHistograms.h
@@ +56,4 @@
>  HISTOGRAM(GC_MARK_MS, 1, 10000, 50, EXPONENTIAL, "Time spent running JS GC mark phase (ms)")
>  HISTOGRAM(GC_SWEEP_MS, 1, 10000, 50, EXPONENTIAL, "Time spent running JS GC sweep phase (ms)")
> +HISTOGRAM(GC_MARK_ROOTS_MS, 1, 200, 50, LINEAR, "Time spent running JS GC mark phase (ms)")
> +HISTOGRAM(GC_MARK_GRAY_MS, 1, 200, 50, LINEAR, "Time spent running JS GC mark phase (ms)")

nit: The descriptions of MARK_GRAY needs to be fixed.
Attachment #651010 - Flags: review?(continuation) → review+
(Assignee)

Comment 2

5 years ago
https://hg.mozilla.org/integration/mozilla-inbound/rev/65bc2e5b574f

Comment 3

5 years ago
https://hg.mozilla.org/mozilla-central/rev/65bc2e5b574f
Status: NEW → RESOLVED
Last Resolved: 5 years ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla17
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