Firefox OS/Performance/Bisecting Regressions

Bisecting Regressions

This page will walk you through finding and bisecting performance regressions in Firefox OS.

Datazilla

Datazilla makes it easy to spot performance regressions in Firefox OS apps. The page that shows the performance test numbers is here: [1].

Performance regressions show up as spikes in the graphs like so (circled in red):

When you find a regression, you need to get the "regression range" for the regression. The regression range is the last known good revision to the first known bad revision for both Gecko and Gaia. To get the last known good revision IDs for both, click on the data point in the graph right before the spike. You will see something like this:

The Gaia and Gecko revisions used in the build and test that generated that data point are shown, circled in red. Write these down. You only need the first 7 characters of the IDs. So in this case you would write down d4655e7 for Gaia and a9f77f8 for Gecko.

To get the first know bad revision, click on the first data point after the spike. You will see something like this: