1369538 - Add telemetry about MediaCacheStream lengths

Status: RESOLVED FIXED

(Core :: Audio/Video: Playback, enhancement)

Description

[Gerald Squelart (he/him) (not at Mozilla since 2022-09-15)]

One idea of avoid file IOs would be to keeo "small-enough" media resources completely in memory.
This probe will help us judge if this could actually be beneficial.

Comment 1

[Gerald Squelart (he/him) (not at Mozilla since 2022-09-15)]

Attachment: Bug 1369538 - Telemetry MEDIACACHESTREAM_LENGTH_KB -

Capture each media stream's length (as provided, otherwise as actually
downloaded), to gauge whether keeping media in memory would have a significant
impact.

Review commit: https://reviewboard.mozilla.org/r/145040/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/145040/

Comment 2

[François Marier [:francois]]

Comment on attachment 8873654 [details]
Bug 1369538 - Telemetry MEDIACACHESTREAM_LENGTH_KB -

https://reviewboard.mozilla.org/r/145040/#review148998

datareview+

::: toolkit/components/telemetry/Histograms.json:8408
(Diff revision 1)
> +    "bug_numbers": [1369538],
> +    "expires_in_version": "60",
> +    "kind": "linear",
> +    "high": 520000,
> +    "n_buckets": 66,
> +    "description": "MediaCacheStream stream length size in KB; Either known size (from HTTP header), or otherwise actually downloaded. Recorded at every MediaCacheStream destruction."

What determines whether it's the known size of the actual download?

Is it the presence of the header?

If so, you could rephrase that part to "Either known size from the HTTP header, if available, or otherwise the size actually downloaded."

Comment 3

[Gerald Squelart (he/him) (not at Mozilla since 2022-09-15)]

Comment on attachment 8873654 [details]
Bug 1369538 - Telemetry MEDIACACHESTREAM_LENGTH_KB -

https://reviewboard.mozilla.org/r/145040/#review148998

> What determines whether it's the known size of the actual download?
> 
> Is it the presence of the header?
> 
> If so, you could rephrase that part to "Either known size from the HTTP header, if available, or otherwise the size actually downloaded."

Done, it's a bit clearer now, thanks for the suggestion.

Comment 4

[Gerald Squelart (he/him) (not at Mozilla since 2022-09-15)]

Comment on attachment 8873654 [details]
Bug 1369538 - Telemetry MEDIACACHESTREAM_LENGTH_KB -

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/145040/diff/1-2/

Comment 5

[Chris Pearce [:cpearce (Not reading bugmail)]]

Comment on attachment 8873654 [details]
Bug 1369538 - Telemetry MEDIACACHESTREAM_LENGTH_KB -

https://reviewboard.mozilla.org/r/145040/#review149008

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/12e990a89018
Telemetry MEDIACACHESTREAM_LENGTH_KB - r=cpearce,francois

Comment 7

[Gerald Squelart (he/him) (not at Mozilla since 2022-09-15)]

Thank you François and Chris for the review.

Comment 8

[Carsten Book [:Tomcat]]

sorry gerald had to back this out for causing https://treeherder.mozilla.org/logviewer.html#?job_id=103988064&repo=autoland

Comment 9

[Pulsebot]

Backout by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/c552b68a1c94
Backed out changeset 12e990a89018 for causing new intermittent leak in browser_devices_get_user_media_in_frame.js

Comment 10

[Gerald Squelart (he/him) (not at Mozilla since 2022-09-15)]

I doubt this patch could have caused this, as it's just reporting a number to Telemetry.

As further proof, the same intermittent leak continues after the backout, e.g., the most appearance (5h ago) is in:
https://treeherder.mozilla.org/#/jobs?repo=autoland&revision=8814375529f130f680f1257c14a678bbc65ce440
This intermittent is now followed by bug 1369731.

So I will reland.

Comment 11

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/a7e36fe5ac72
Telemetry MEDIACACHESTREAM_LENGTH_KB - r=cpearce,francois

Comment 12

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

https://hg.mozilla.org/mozilla-central/rev/a7e36fe5ac72