For Developers‎ > ‎Speed Infra‎ > ‎

FAQ for when a perf regression bug is assigned to you

Finding more information from the perf dashboard

  • See related regressions and improvements around the same time as your commit at<commit-position>
  • Many tests are comprised of page sets. Click the checkboxes in the chart legend to see individual pages. Some pages usually regress more than others, which may make it easier to reproduce.
  • Many tests upload traces to the perf dashboard. They will show up in the graph tooltips for individual pages.

Reproducing performance regressions locally

  • The command is found at the top of the bisect output. If it's a telemetry test, running tools\perf\run_benchmark <chart name> will run locally. 
  • You can get more info by getting and analyzing a trace; you can pass a --profiler=... flag to the Telemetry run_benchmark command. 

Reproducing performance regressions on the performance try bots

If the test is a Telemetry test, see:

You can also directly trigger a perf try job:
  • Edit src/tools/run-perf-test.cfg in a new git branch and follow the instructions in that file. (Note: strip any src/ directories from the head of relative path names.) Alternatively, use run_benchmark try and modify the automatically uploaded CL.
  • Then run git cl try -b bot-name --svn_repo='svn://' where bot-name is one of the bots on