2.05 - 2% speedometer3 TodoMVC-jQuery/Adding100Items/Sync / speedometer3 TodoMVC-jQuery/total + 3 more (OSX) regression on Wed November 12 2025
Categories
(Core :: JavaScript: GC, defect, P1)
Tracking
()
| Tracking | Status | |
|---|---|---|
| firefox-esr140 | --- | unaffected |
| firefox145 | --- | unaffected |
| firefox146 | --- | unaffected |
| firefox147 | --- | affected |
People
(Reporter: intermittent-bug-filer, Unassigned)
References
(Blocks 1 open bug, Regression)
Details
(Keywords: perf, perf-alert, regression)
Perfherder has detected a browsertime performance regression from push 7cc46dd9bdfaafeaf9905a575697366b4f3f07a8. 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 aesanu@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) | Performance Profiles |
|---|---|---|---|---|---|
| 2% | speedometer3 TodoMVC-jQuery/Adding100Items/Sync | macosx1500-aarch64-shippable | fission webrender | 18.83 -> 19.22 | Before/After |
| 2% | speedometer3 TodoMVC-jQuery/CompletingAllItems/Sync | macosx1500-aarch64-shippable | fission webrender | 31.94 -> 32.59 | Before/After |
| 2% | speedometer3 TodoMVC-jQuery/CompletingAllItems/total | macosx1500-aarch64-shippable | fission webrender | 32.97 -> 33.64 | Before/After |
| 2% | speedometer3 TodoMVC-JavaScript-ES6-Webpack-Complex-DOM/Adding100Items/total | macosx1500-aarch64-shippable | fission webrender | 12.84 -> 13.10 | Before/After |
| 2% | speedometer3 TodoMVC-jQuery/total | macosx1500-aarch64-shippable | fission webrender | 69.83 -> 71.22 | Before/After |
Improvements:
| Ratio | Test | Platform | Options | Absolute values (old vs new) | Performance Profiles |
|---|---|---|---|---|---|
| 22% | jetstream3 proxy-mobx-Worst | macosx1500-aarch64-shippable | fission webrender | 2.34 -> 1.82 | Before/After |
| 21% | jetstream3 Air-First | android-hw-a55-14-0-aarch64-shippable | webrender | 48.89 -> 38.43 | |
| 12% | jetstream3 proxy-vue-Worst | android-hw-a55-14-0-aarch64-shippable | fission webrender | 36.38 -> 32.14 | |
| 10% | jetstream3 babel-minify-wtb-First | windows11-64-24h2-shippable | fission webrender | 104.83 -> 93.93 | |
| 10% | jetstream3 proxy-vue-Worst | android-hw-a55-14-0-aarch64-shippable | webrender | 36.72 -> 32.95 | |
| ... | ... | ... | ... | ... | ... |
| 2% | speedometer3 TodoMVC-Vue/Adding100Items/Async | macosx1500-aarch64-shippable | fission webrender | 5.69 -> 5.57 | Before/After |
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 aesanu@mozilla.com to do that for you.
You can run all of these tests on try with ./mach try perf --alert 47480
The following documentation link provides more information about this command.
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Comment 1•3 months ago
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Set release status flags based on info from the regressing bug 1827612
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Updated•3 months ago
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Updated•3 months ago
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Comment 2•3 months ago
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The regressions are small and only appear to affect macOS whereas there are far more improvements, and they are larger and affect more platforms.
There are now a lot more improvements in the alert but I'm not sure all of them are actually due to this change. Regardless this is something we want to keep (it's a dependency for bug 1995021) so I'm going to close this as WONTFIX.
Description
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