1568107 - Add telemetry to nsRefreshDisplay::Tick

Status: RESOLVED FIXED

(Core :: Layout, task, P3)

Description

[u480271]

The rendering team is interested in collecting telemetry to determine if effort to optimize layout is required and where that effort should be focused.

To aid this effort, we'd like to understand what percentage of time in expensive refresh display ticks is attributable to layout, collect data for expensive refresh ticks and attribute to which sub-system that time was spent in.

Comment 1

[u480271]

Attachment: Bug 1568107 - Collect nsRefreshDriver::Tick phase weighted telemetry.

For a slow tick, where the processing time takes longer than 1/60th sec, record
telemetry for the percentage of that time spent in each sub-system processing
events (ev), style (st), layout (lo), and display (di).

Comment 2

[u480271]

Attachment: data-review-request.txt

Comment 3

[u480271]

Comment on attachment 9079910 [details]
Bug 1568107 - Collect nsRefreshDriver::Tick phase weighted telemetry.

Looking for general feedback from :heycam, asking for review from :mattwoodrow because he's dealt with telemetry for retained display list.

Comment 4

[Emilio Cobos Álvarez (:emilio)]

So one of the issues with this is that explicit layout flushes from e.g. script running on the page may make the layout contribution to the total frame be underrepresented. Do we have a plan to fix or mitigate that?

Comment 5

[Tim Smith (inactive) 👨‍🔬 [:tdsmith]]

Data stewardship programming note: chutten's away this week, but you can flag any of the other data stewards for review if you'd like a response sooner: https://wiki.mozilla.org/Firefox/Data_Collection

Comment 6

[u480271]

(In reply to Tim Smith 👨‍🔬 [:tdsmith] from comment #5)

Data stewardship programming note: chutten's away this week, but you can flag any of the other data stewards for review if you'd like a response sooner: https://wiki.mozilla.org/Firefox/Data_Collection

Thanks. I looked at the list of stewards and :chutten was the only one tagged as Telemetry.

Comment 7

[u480271]

(In reply to Emilio Cobos Álvarez (:emilio) from comment #4)

So one of the issues with this is that explicit layout flushes from e.g. script running on the page may make the layout contribution to the total frame be underrepresented. Do we have a plan to fix or mitigate that?

Emilio, this is the start of more telemetry collection relating to layout to come.

Comment 8

[Tim Smith (inactive) 👨‍🔬 [:tdsmith]]

Comment on attachment 9079916 [details]
data-review-request.txt

Thanks for the thoughtful documentation of the collection and its context!

--

1) Is there or will there be **documentation** that describes the schema for the ultimate data set in a public, complete, and accurate way?

Yes, in Histograms.json.

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

Yes, the Firefox telemetry opt-out.

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

n/a; temporary collection.

4) Using the **[category system of data types](https://wiki.mozilla.org/Firefox/Data_Collection)** on the Mozilla wiki, what collection type of data do the requested measurements fall under?

Category 1, technical data.

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

Default-on, in prerelease channels.

6) Does the instrumentation include the addition of **any *new* identifiers** (whether anonymous or otherwise; e.g., username, random IDs, etc.  See the appendix for more details)?

No.

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

Yes.

8) Does there need to be a check-in in the future to determine whether to renew the data? (Yes/No)

Yes, :kamidphish is responsible for making a decision about whether to renew the collection in a year.

9) Does the data collection use a third-party collection tool?

No.

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/b99bec688dea
Collect nsRefreshDriver::Tick phase weighted telemetry. r=mattwoodrow,heycam

Comment 10

[Andrei Ciure[:aciure]]

https://hg.mozilla.org/mozilla-central/rev/b99bec688dea