Closed Bug 1607545 Opened 3 years ago Closed 3 years ago

about_home_topsites_first_paint scalar is recorded on first about:home sighting even if it wasn't the first page loaded


(Firefox :: New Tab Page, defect)

Not set



Firefox 75
Tracking Status
firefox75 --- verified


(Reporter: mconley, Assigned: mconley)


(Blocks 1 open bug)


(Whiteboard: [fxperf:p1])


(1 file, 1 obsolete file)


  1. Ensure Firefox is configured to load about:home by default, and not to restore the previous session.
  2. Launch Firefox Nightly via ./mach with ./mach run
  3. Once the initial tab finishes loading, open a new tab, and browse to about:telemetry
  4. Choose "Scalars" along the left-hand side, and note that the about_home_topsites_first_paint scalar is (correctly) absent.
  5. Open a new window.
  6. Reload about:telemetry


The about_home_topsites_first_paint scalar should still be missing.


The about_home_topsites_first_paint was recorded.

This might account for some of the truly egregious measurements we're getting on the about_home_topsites_first_paint probe, which is supposed to measure the time between process start and rendering the initial about:home.

Blocks: 1610558

Hey k88hudson, if there's someone more appropriate to review this, or you're bogged down, let me know and I'll redirect. Thanks!

Flags: needinfo?(khudson)
Pushed by
Don't record about_home_topsites_first_paint scalar unless the first windows initial tab is about:home. r=k88hudson
Backout by
Backed out changeset cfb9cc9ee352 for node failures on a CLOSED TREE

Backed out changeset cfb9cc9ee352 (bug 1607545) for node failures

Push that started the failures:

Failure log:


[task 2020-01-24T22:54:06.508Z] TEST-UNEXPECTED-FAIL karma | activity-stream:TelemetryFeed:#saveSessionPerfData should call maybeRecordTopsitesPainted when url is about:home and topsites_first_painted_ts is given: AboutNewTabStartupRecorder is not defined
[task 2020-01-24T22:54:06.508Z] saveSessionPerfData@http://localhost:9876/base/test/unit/unit-entry.js?e6e7df87a2ee16648a18118dc3af3e07cb701552:150742:77205
[task 2020-01-24T22:54:06.508Z] @http://localhost:9876/base/test/unit/unit-entry.js?e6e7df87a2ee16648a18118dc3af3e07cb701552:150140:16
[task 2020-01-24T22:54:06.508Z]
[task 2020-01-24T22:54:06.508Z] TEST START | sasslint
[task 2020-01-24T22:54:08.020Z] { karmaPassed: false, sasslintPassed: true }
[task 2020-01-24T22:54:08.020Z] CODE 1
[fetches 2020-01-24T22:54:08.023Z] removing /builds/worker/fetches
[fetches 2020-01-24T22:54:08.057Z] finished
[taskcluster 2020-01-24 22:54:08.389Z] === Task Finished ===
[taskcluster 2020-01-24 22:54:08.389Z] Unsuccessful task run with exit code: 1 completed in 268.196 seconds

Flags: needinfo?(mconley)
Attachment #9123931 - Attachment is obsolete: true
Pushed by
Don't record about_home_topsites_first_paint scalar unless the first windows initial tab is about:home. r=k88hudson

Oh ha ha. I see now why it was a separate phabricator revision with the original getting backed out. Sorry for the delays!

Flags: needinfo?(mconley)
Flags: needinfo?(khudson)
Closed: 3 years ago
Resolution: --- → FIXED
Target Milestone: --- → Firefox 75

I have verified that this issue is no longer reproducible with the latest Firefox Nightly (75.0a1 Build ID - 20200212093201) installed, on Windows 10 x64, Ubuntu 18.04 x64 and Mac 10.15.2. Now, I can confirm that after following the steps from the description the about_home_topsites_first_paint scalar is not displayed on the "about:telemetry" page.

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