1637642 - Add missing GC telemetry for the prepare and weak marking phases

Status: RESOLVED FIXED

(Core :: JavaScript: GC, task, P3)

Description

[Jon Coppeard (:jonco)]

Currently there's no individual telemetry for the 'prepare' phase, which is unfortunate as this is non-incremental and something that shows up in GC_SLOW_PHASE. Also there's no telemetry for weak marking which is again unfortunate as it's something we're working on improving with the incremental weak map marking work.

Comment 1

[Jon Coppeard (:jonco)]

Attachment: Bug 1637642 - Add telemetry for GC preparation phase that occurs before root marking r?sfink

Depends on D75147

Comment 2

[Jon Coppeard (:jonco)]

Attachment: Bug 1637642 - Add telemetry for weak marking phases r?sfink

Depends on D75148

Comment 3

[Jon Coppeard (:jonco)]

Attachment: data_collection_request.txt

Requesting data review.

Comment 4

[Chris H-C :chutten]

Comment on attachment 9148080 [details]
data_collection_request.txt

PRELIMINARY NOTES:
You filled the request form out exceedingly well. It was clear and easy to follow. Thank you!

DATA COLLECTION REVIEW RESPONSE:

    Is there or will there be documentation that describes the schema for the ultimate data set available publicly, complete and accurate?

Yes. This collection is Telemetry so is documented in its definitions file [Histograms.json](https://hg.mozilla.org/mozilla-central/file/tip/toolkit/components/telemetry/Histograms.json) and the [Probe Dictionary](https://telemetry.mozilla.org/probe-dictionary/).

    Is there a control mechanism that allows the user to turn the data collection on and off?

Yes. This collection is Telemetry so can be controlled through Firefox's Preferences.

    If the request is for permanent data collection, is there someone who will monitor the data over time?

Yes, :jonco is responsible.

    Using the category system of data types on the Mozilla wiki, what collection type of data do the requested measurements fall under?

Category 1, Technical.

    Is the data collection request for default-on or default-off?

Default on for all channels.

    Does the instrumentation include the addition of any new identifiers?

No.

    Is the data collection covered by the existing Firefox privacy notice?

Yes.

    Does there need to be a check-in in the future to determine whether to renew the data?

No. This collection is permanent.

---
Result: datareview+

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/71f6facd478a
Add telemetry for GC preparation phase that occurs before root marking r=sfink
https://hg.mozilla.org/integration/autoland/rev/0e0c8a33d904
Add telemetry for weak marking phases r=sfink

Comment 6

[Noemi Erli[:noemi_erli]]

https://hg.mozilla.org/mozilla-central/rev/71f6facd478a
https://hg.mozilla.org/mozilla-central/rev/0e0c8a33d904