I noticed Firefox getting janky not long after startup and discovered that TestPilot's remote-experiment-loader.js was monopolizing the main thread for about 600ms. From looking at the profile alone, it looks like the time is being spent opening a Zip archive and checking file mtimes. Profile: http://people.mozilla.com/~bgirard/cleopatra/#report=3a3d37e58eacaa8ab13c723a75a31da1b5aa474c TestPilot version 1.2.2 We should look into moving some of the I/O off the main thread. I'm told it's not currently possible to open archives off the main thread.
btw, should pass ".js$" into findEntries in http://email@example.com/modules/jar-code-store.js#53
Fixed by removing test pilot 1. Any new versions we integrate should not have this kind of problem.