13.5% facebook-nav.marketplace loadtime (Linux) regression on Tue August 19 2025
Categories
(Core :: Networking, defect)
Tracking
()
| Tracking | Status | |
|---|---|---|
| firefox-esr128 | --- | unaffected |
| firefox-esr140 | --- | unaffected |
| firefox142 | --- | unaffected |
| firefox143 | --- | unaffected |
| firefox144 | --- | affected |
People
(Reporter: intermittent-bug-filer, Unassigned)
References
(Depends on 1 open bug, Regression)
Details
(Keywords: perf, perf-alert, regression)
Perfherder has detected a browsertime performance regression from push 8537f385afd64dffe8195d44bdcb7a7df27cf321. As author of one of the patches included in that push, we need your help to address this regression.
Please acknowledge, and begin investigating this alert within 3 business days, or the patch(es) may be backed out in accordance with our regression policy. Our guide to handling regression bugs has information about how you can proceed with this investigation.
If you have any questions or need any help with the investigation, please reach out to fbilt@mozilla.com. Alternatively, you can find help on Slack by joining #perf-help, and on Matrix you can find help by joining #perftest.
Regressions:
| Ratio | Test | Platform | Options | Absolute values (old vs new) |
|---|---|---|---|---|
| 14% | facebook-nav.marketplace loadtime | linux1804-64-shippable-qr | cold fission webrender | 627.39 -> 712.06 |
Improvements:
| Ratio | Test | Platform | Options | Absolute values (old vs new) |
|---|---|---|---|---|
| 20% | facebook-nav.marketplace fcp | linux1804-64-shippable-qr | cold fission webrender | 458.81 -> 366.60 |
| 9% | facebook-nav.marketplace PerceptualSpeedIndex | linux1804-64-shippable-qr | cold fission webrender | 513.79 -> 467.82 |
Details of the alert can be found in the alert summary, including links to graphs and comparisons for each of the affected tests.
If you need the profiling jobs you can trigger them yourself from treeherder job view or ask fbilt@mozilla.com to do that for you.
You can run all of these tests on try with ./mach try perf --alert 46391
The following documentation link provides more information about this command.
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Comment 1•7 months ago
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Set release status flags based on info from the regressing bug 1978936
We see a compelling win for fcp and PerceptualSpeedIndex, and we believe that these speedups cause more items get added to the load group so it takes longer to do the full loadtime because we end up loading more resources. This is somewhat expected and not a real loss in performance.
Description
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