Peptest: A new harness for testing responsiveness

While responsiveness is one of the main goals for Firefox this quarter, we still don’t quite have the means to measure and test our progress towards this goal. The good news is that there are, and have been for some time, several efforts to fix this problem. Back in June, Ted wrote some event tracing instrumentation that gives us a reasonable idea of when the browser becomes unresponsive. This event tracer is already being used by some Talos tests which gives us a good general idea of whether or not Firefox is more or less responsive than it was previously. What it doesn’t give us is a method for developers to write their own tests and determine whether a specific action or feature they are working on is causing unresponsivness.

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