Bug: 2.04 - 1.95% google-mail FirstVisualChange / google-mail FirstVisualChange (Windows) regression on Tue August 8 2023
Status: NEW
Priority: --
Created: 2023-08-17 13:50:50+00:00
Resolved: 2023-09-07 15:29:55+00:00

Perfherder has detected a browsertime performance regression from push [80fde27f01a774b21528e4955162e350e4ee1f23](https://hg.mozilla.org/integration/autoland/pushloghtml?changeset=80fde27f01a774b21528e4955162e350e4ee1f23). 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** | 
|--|--|--|--|--|--| 
| [2%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,3778025,1,13)  | [google-mail](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#google-mail-d) FirstVisualChange | windows10-64-shippable-qr | cold fission webrender | 1,077.49 -> 1,099.51 |  |
| [2%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,3778025,1,13)  | [google-mail](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#google-mail-d) FirstVisualChange | windows10-64-shippable-qr | cold fission webrender | [1,080.28](https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/BVv-1FiHRcaYKEIlQi0u5A/runs/0/artifacts/public/test_info/browsertime-results.tgz) -> [1,101.38](https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/U8u--vd3SDaBoQ21Sb_qdQ/runs/0/artifacts/public/test_info/browsertime-results.tgz) |  |
### Improvements:

| **Ratio** | **Test** | **Platform** | **Options** | **Absolute values (old vs new)** |  **Performance Profiles** | 
|--|--|--|--|--|--| 
| [21%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,4405608,1,13)  | [twitter](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#twitter-d) FirstVisualChange | linux1804-64-shippable-qr | bytecode-cached cold fission webrender | 319.12 -> 251.77 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FD_c8Cr5VT_KzlFzJ3BMIlw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_twitter.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FbutfNMMwQH2aODXk127nGg%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_twitter.zip) |
| [5%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,4405613,1,13)  | [twitter](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#twitter-d) fcp | linux1804-64-shippable-qr | bytecode-cached cold fission webrender | 196.54 -> 186.75 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FD_c8Cr5VT_KzlFzJ3BMIlw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_twitter.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FbutfNMMwQH2aODXk127nGg%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_twitter.zip) |
| [4%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,4405610,1,13)  | [twitter](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#twitter-d) PerceptualSpeedIndex | linux1804-64-shippable-qr | bytecode-cached cold fission webrender | 879.05 -> 841.19 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FD_c8Cr5VT_KzlFzJ3BMIlw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_twitter.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FbutfNMMwQH2aODXk127nGg%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_twitter.zip) |


Details of the alert can be found in the [alert summary](https://treeherder.mozilla.org/perfherder/alerts?id=39339), 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 offending 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.

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