Bug: 9.33 - 7.77% speedometer3 cpuTime / speedometer3 cpuTime (Linux) regression on Fri September 20 2024
Status: RESOLVED
Priority: --
Resolution: WONTFIX
Created: 2024-09-25 07:14:34+00:00
Resolved: 2024-10-09 17:07:53+00:00

Perfherder has detected a browsertime performance regression from push [a90481dcd451b1b03055be15830b257ce3f4872a](https://hg.mozilla.org/integration/autoland/pushloghtml?changeset=a90481dcd451b1b03055be15830b257ce3f4872a). As author of one of the patches included in that push, we need your help to address this regression.

### Regressions:

| **Ratio** | **Test** | **Platform** | **Options** | **Absolute values (old vs new)** |  **Performance Profiles** | 
|--|--|--|--|--|--| 
| [9%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,195289,1,13)  | [speedometer3](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#speedometer3-d) cpuTime | linux1804-64-nightlyasrelease-qr | fission webrender | [635.83](https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/VW29K3bLQGiMtyVSkdoaxQ/runs/0/artifacts/public/test_info/browsertime-results.tgz) -> [695.17](https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/Un0zTBNbSpm9L1lBTzSTcw/runs/0/artifacts/public/test_info/browsertime-results.tgz) | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FVW29K3bLQGiMtyVSkdoaxQ%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_speedometer3.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FUn0zTBNbSpm9L1lBTzSTcw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_speedometer3.zip) |
| [8%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,195289,1,13)  | [speedometer3](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#speedometer3-d) cpuTime | linux1804-64-nightlyasrelease-qr | fission webrender | 638.43 -> 688.05 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FVW29K3bLQGiMtyVSkdoaxQ%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_speedometer3.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FUn0zTBNbSpm9L1lBTzSTcw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_speedometer3.zip) |


Details of the alert can be found in the [alert summary](https://treeherder.mozilla.org/perfherder/alerts?id=2220), including links to graphs and comparisons for each of the affected tests. Please follow our [guide to handling regression bugs](https://wiki.mozilla.org/TestEngineering/Performance/Handling_regression_bugs) and **let us know your plans within 3 business days, or the patch(es) may be backed out** in accordance with our [regression policy](https://www.mozilla.org/en-US/about/governance/policies/regressions/).

If you need the profiling jobs you can trigger them yourself from treeherder job view or ask a sheriff to do that for you.

You can run all of these tests on try with `./mach try perf --alert 2220`

The following [documentation link](https://firefox-source-docs.mozilla.org/testing/perfdocs/mach-try-perf.html#running-alert-tests) provides more information about this command.

For more information on performance sheriffing please see our [FAQ](https://wiki.mozilla.org/TestEngineering/Performance/FAQ).

If you have any questions, please do not hesitate to reach out to aesanu@mozilla.com.