1772429 - Remove or update probes expiring in Firefox 104: CONTENT_PROCESS_*

Status: RESOLVED FIXED

(Core :: Performance Engineering, task)

Description

[telemetry-probes]

The following Firefox probes will expire in the next major Firefox nightly release: version 104 [1].

CONTENT_PROCESS_COUNT
CONTENT_PROCESS_PRECISE_COUNT
CONTENT_PROCESS_TIME_SINCE_LAST_LAUNCH_MS
content.process_max_precise

What to do about this:

1. If one, some, or all of the metrics are no longer needed, please remove them from their definitions files (Histograms.json, Scalars.yaml, Events.yaml).
2. If one, some, or all of the metrics are still required, please submit a Data Collection Review [2] and patch to extend their expiry. There is a shorter form for data collection renewal [3].

If you have any problems, please ask for help on the #data-help Slack channel or the #telemetry Matrix room at https://chat.mozilla.org/#/room/#telemetry:mozilla.org. We'll give you a hand.

Your Friendly, Neighborhood Telemetry Team

[1] https://wiki.mozilla.org/Release_Management/Calendar
[2] https://wiki.mozilla.org/Firefox/Data_Collection
[3] https://github.com/mozilla/data-review/blob/master/renewal_request.md

This is an automated message sent from probe-scraper. See https://github.com/mozilla/probe-scraper for details.

Comment 1

[Markus Stange [:mstange]]

Randell, is this probe worth refreshing?

Comment 2

[Benjamin De Kosnik [:bdekoz]]

Some triage.

Last reviewed 6 months ago for Firefox 98: https://bugzilla.mozilla.org/show_bug.cgi?id=1745268

From looking at STMO, these probes are used in the following saved queries:
payload.histograms.content_process_count == 1, from a year ago, unpublished
payload.histograms.content_process_precise_count == 0
payload.histograms.content_process_time_since_last_launch_ms == 0
payload.processes.parent.scalars.content_process_max_precise == 0

Ie, they are largely unused. What is or was used:

total crashes per content process for fission:
https://sql.telemetry.mozilla.org/queries/76430/source

number of content processes
https://sql.telemetry.mozilla.org/queries/78752/source

In a related area, the payload.histograms.content_documents_destroyed/payload.histograms.top_level_content_documents_destroyed are used in existing queries for use counters.

From looking at the originating bugzillas, it seems to me that these modifications might be useful:

1. CONTENT_PROCESS_COUNT and CONTENT_PROCESS_PRECISE_COUNT are mostly the same. Recommend: dropping CONTENT_PROCESS_COUNT and continuing CONTENT_PROCESS_PRECISE_COUNT, which looks to have superior bucketing

2. Continue CONTENT_PROCESS_TIME_SINCE_LAST_LAUNCH_MS, and note that maybe MS wasn't the right unit for this probe, given the distribution. Because this is exponential histogram it's not a deal breaker. This probe looks like it is/can be a useful guardrail type probe for future releases. Would like a fusion-related SME to comment, and see Barret picked Randall for the earlier iterations.

3. content_process_max_precise continue, useful scalar for guardrail type as above.

Comment 3

[Barret Rennie [:barret] (they/them)]

:bdekoz if you decide to remove this telemetry (which seems unused) here is a patch

Comment 4

[Barret Rennie [:barret] (they/them)]

Attachment: Bug 1772429 - Remove unused content process count / launch delta telemetry r=bdekoz

Comment 5

[Florian Quèze [:florian]]

The code of these probes uses a 5 minutes repeating timer that keeps running all the time even when the user is completely idle. Currently this timer is pointless as the probe has expired several releases ago. I would like to remove the timer. Benjamin, are you planning to update the probes (if so it would be nice to implement it in a way that doesn't use a timer; it could instead record data when content processes are started and stopped), or should we go ahead and remove it?

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/4ac1b84a400b
Remove unused content process count / launch delta telemetry r=bdekoz

Comment 7

[Atila Butkovits]

https://hg.mozilla.org/mozilla-central/rev/4ac1b84a400b