Bug: 7.29 - 4.62% welcome FirstVisualChange / welcome ContentfulSpeedIndex + 7 more (Linux, Windows) regression on Mon February 3 2025
Status: NEW
Priority: P1
Created: 2025-02-10 13:18:47+00:00
Resolved: 2025-03-03 16:13:39+00:00

Perfherder has detected a browsertime performance regression from push [07b3408167ff29f5f2cab486a05eeb482088ff81](https://hg.mozilla.org/integration/autoland/pushloghtml?changeset=07b3408167ff29f5f2cab486a05eeb482088ff81). 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** | 
|--|--|--|--|--|--| 
| [7%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,3937754,1,13)  | [welcome](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#welcome-c) FirstVisualChange | linux1804-64-shippable-qr | cold fission webrender | [1,170.47](https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/X4yXm-mZQyeZoNF7CteBHw/runs/0/artifacts/public/test_info/browsertime-results.tgz) -> [1,255.84](https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/UyymBnBLSpGUEy2sfgOqQw/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%2FX4yXm-mZQyeZoNF7CteBHw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_welcome.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FUyymBnBLSpGUEy2sfgOqQw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_welcome.zip) |
| [7%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,3937754,1,13)  | [welcome](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#welcome-c) FirstVisualChange | linux1804-64-shippable-qr | cold fission webrender | 1,171.80 -> 1,250.68 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FX4yXm-mZQyeZoNF7CteBHw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_welcome.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FUyymBnBLSpGUEy2sfgOqQw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_welcome.zip) |
| [6%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,3937753,1,13)  | [welcome](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#welcome-c) SpeedIndex | linux1804-64-shippable-qr | cold fission webrender | 1,209.88 -> 1,286.97 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FX4yXm-mZQyeZoNF7CteBHw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_welcome.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FUyymBnBLSpGUEy2sfgOqQw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_welcome.zip) |
| [6%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,3937758,1,13)  | [welcome](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#welcome-c) PerceptualSpeedIndex | linux1804-64-shippable-qr | cold fission webrender | 1,212.43 -> 1,284.78 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FX4yXm-mZQyeZoNF7CteBHw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_welcome.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FUyymBnBLSpGUEy2sfgOqQw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_welcome.zip) |
| [6%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,85294,1,13)  | [welcome](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#welcome-c) FirstVisualChange | windows11-64-shippable-qr | cold fission webrender | 1,108.08 -> 1,172.57 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FOhiHYB0MTum1mTNdYdWtVw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_welcome.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FHhckc7j8QxqsfTD_JPQnqw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_welcome.zip) |
| [5%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,85297,1,13)  | [welcome](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#welcome-c) SpeedIndex | windows11-64-shippable-qr | cold fission webrender | 1,144.24 -> 1,206.98 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FOhiHYB0MTum1mTNdYdWtVw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_welcome.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FHhckc7j8QxqsfTD_JPQnqw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_welcome.zip) |
| [5%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,3937756,1,13)  | [welcome](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#welcome-c) ContentfulSpeedIndex | linux1804-64-shippable-qr | cold fission webrender | 1,201.18 -> 1,266.74 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FX4yXm-mZQyeZoNF7CteBHw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_welcome.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FUyymBnBLSpGUEy2sfgOqQw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_welcome.zip) |
| [5%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,85296,1,13)  | [welcome](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#welcome-c) PerceptualSpeedIndex | windows11-64-shippable-qr | cold fission webrender | 1,147.39 -> 1,205.21 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FOhiHYB0MTum1mTNdYdWtVw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_welcome.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FHhckc7j8QxqsfTD_JPQnqw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_welcome.zip) |
| [5%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,85293,1,13)  | [welcome](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#welcome-c) ContentfulSpeedIndex | windows11-64-shippable-qr | cold fission webrender | 1,137.15 -> 1,189.66 | [Before](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FOhiHYB0MTum1mTNdYdWtVw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_welcome.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FHhckc7j8QxqsfTD_JPQnqw%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_welcome.zip) |
| [3%](https://treeherder.mozilla.org/perfherder/graphs?timerange=1209600&series=autoland,3776885,1,13)  | [microsoft](https://firefox-source-docs.mozilla.org/testing/perfdocs/raptor.html#microsoft-d) PerceptualSpeedIndex | linux1804-64-shippable-qr | cold fission webrender | [1,353.64](https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/TYsyZsCnRC6VW2EMz_D8eA/runs/0/artifacts/public/test_info/browsertime-results.tgz) -> [1,388.97](https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/XXwyhzprSHORq5wp9_n4_Q/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%2FTYsyZsCnRC6VW2EMz_D8eA%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_microsoft.zip)/[After](https://profiler.firefox.com/from-url/https%3A%2F%2Ffirefox-ci-tc.services.mozilla.com%2Fapi%2Fqueue%2Fv1%2Ftask%2FXXwyhzprSHORq5wp9_n4_Q%2Fruns%2F0%2Fartifacts%2Fpublic%2Ftest_info%2Fprofile_microsoft.zip) |


Details of the alert can be found in the [alert summary](https://treeherder.mozilla.org/perfherder/alerts?id=43760), 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 43760`

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.