Bug: 4.6 - 2.08% google-mail FirstVisualChange / twitter loadtime + 28 more (Windows) regression on Sat September 28 2024
Status: RESOLVED
Priority: --
Resolution: FIXED
Created: 2024-10-01 14:21:47+00:00
Resolved: 2024-10-24 00:42:16+00:00

Perfherder has detected a browsertime performance regression from push [e488803f8f2d64a0eb122de50f6f74e596f012ff](https://hg.mozilla.org/integration/autoland/pushloghtml?changeset=e488803f8f2d64a0eb122de50f6f74e596f012ff). 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** | 
|--|--|--|--|--|--| 
| [5%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,85112,1,13)  | [google-mail](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#google-mail-d) FirstVisualChange | windows11-64-shippable-qr | fission warm webrender | 545.83 -> 570.96 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FDAop8Sp5QTmdKuBEjObTGQ%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_google-mail.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FUD9iS75RT7qeN2uwlvxJKA%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_google-mail.zip) |
| [5%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,85111,1,13)  | [google-mail](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#google-mail-d) ContentfulSpeedIndex | windows11-64-shippable-qr | fission warm webrender | 546.83 -> 571.96 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FDAop8Sp5QTmdKuBEjObTGQ%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_google-mail.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FUD9iS75RT7qeN2uwlvxJKA%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_google-mail.zip) |
| [5%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,85559,1,13)  | [office](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#office-d) ContentfulSpeedIndex | windows11-64-shippable-qr | fission warm webrender | 299.43 -> 312.99 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FHVM4S8PhTqaIkMf6nx9-Pw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_office.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FQylOG9f2TRaDkLE502yteQ%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_office.zip) |
| [4%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,85115,1,13)  | [google-mail](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#google-mail-d) SpeedIndex | windows11-64-shippable-qr | fission warm webrender | 548.06 -> 572.38 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FDAop8Sp5QTmdKuBEjObTGQ%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_google-mail.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FUD9iS75RT7qeN2uwlvxJKA%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_google-mail.zip) |
| [4%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,85114,1,13)  | [google-mail](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#google-mail-d) PerceptualSpeedIndex | windows11-64-shippable-qr | fission warm webrender | 552.80 -> 577.09 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FDAop8Sp5QTmdKuBEjObTGQ%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_google-mail.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FUD9iS75RT7qeN2uwlvxJKA%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_google-mail.zip) |
| [4%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,85357,1,13)  | [instagram](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#instagram-d) largestContentfulPaint | windows11-64-shippable-qr | fission warm webrender | 577.35 -> 599.21 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2Fa7mDTlwBRtKLYcXT6XLCbg%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_instagram.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FQR05npW6SueV7oGtuppfZw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_instagram.zip) |
| [4%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,86016,1,13)  | [pinterest](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#pinterest-d) PerceptualSpeedIndex | windows11-64-shippable-qr | fission warm webrender | 711.38 -> 736.39 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FVPXJuwxETVGvTBj3pAAdvw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_pinterest.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2Fe_NKd-33R-OyrYaJrc5_6Q%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_pinterest.zip) |
| [4%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,86022,1,13)  | [pinterest](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#pinterest-d) loadtime | windows11-64-shippable-qr | fission warm webrender | 604.25 -> 625.40 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FVPXJuwxETVGvTBj3pAAdvw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_pinterest.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2Fe_NKd-33R-OyrYaJrc5_6Q%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_pinterest.zip) |
| [3%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,85565,1,13)  | [office](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#office-d) fcp | windows11-64-shippable-qr | fission warm webrender | 205.44 -> 211.82 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FHVM4S8PhTqaIkMf6nx9-Pw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_office.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FQylOG9f2TRaDkLE502yteQ%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_office.zip) |
| [3%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,85555,1,13)  | [office](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#office-d) fcp | windows11-64-shippable-qr | cold fission webrender | 345.34 -> 356.00 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FHVM4S8PhTqaIkMf6nx9-Pw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_office.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FQylOG9f2TRaDkLE502yteQ%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_office.zip) |
|...|...|...|...|...|...|
| [2%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,86172,1,13)  | [twitter](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#twitter-d) PerceptualSpeedIndex | windows11-64-shippable-qr | bytecode-cached fission warm webrender | [306.45](https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/UhmVjjNJRRidIDa5NMwSzQ/runs/0/artifacts/public/test_info/browsertime-results.tgz) -> [313.81](https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/DgVe9PzcToWTr16YZVLbmQ/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%2FUhmVjjNJRRidIDa5NMwSzQ%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%2FDgVe9PzcToWTr16YZVLbmQ%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_twitter.zip) |
| [2%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,85120,1,13)  | [google-mail](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#google-mail-d) loadtime | windows11-64-shippable-qr | fission warm webrender | 215.20 -> 220.28 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FDAop8Sp5QTmdKuBEjObTGQ%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_google-mail.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FUD9iS75RT7qeN2uwlvxJKA%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_google-mail.zip) |
| [2%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,86173,1,13)  | [twitter](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#twitter-d) SpeedIndex | windows11-64-shippable-qr | bytecode-cached fission warm webrender | 468.64 -> 479.02 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FUhmVjjNJRRidIDa5NMwSzQ%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%2FDgVe9PzcToWTr16YZVLbmQ%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_twitter.zip) |
| [2%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,86171,1,13)  | [twitter](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#twitter-d) LastVisualChange | windows11-64-shippable-qr | bytecode-cached fission warm webrender | 648.96 -> 663.11 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FUhmVjjNJRRidIDa5NMwSzQ%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%2FDgVe9PzcToWTr16YZVLbmQ%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_twitter.zip) |
| [2%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,86178,1,13)  | [twitter](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#twitter-d) loadtime | windows11-64-shippable-qr | bytecode-cached fission warm webrender | 307.93 -> 314.33 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FUhmVjjNJRRidIDa5NMwSzQ%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%2FDgVe9PzcToWTr16YZVLbmQ%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=2294), 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 2294`

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 fbilt@mozilla.com.