Telemetry infrastructure has only been deployed for week, but we are already gathering interesting data:
- Memory usage from about:memory gives us an idea of what constitutes typical memory usage for Firefox
- Cycle-collection overhead, stats tell us about browser pauses due to memory cleanup
- Detailed startup profiling tells us whether our new library preloading logic is effective
- Info on whether the browser was shutdown correctly will help us diagnose shutdown problems
- Plugin enumeration timing to make sure my faster plugin enumeration stays fast
- HTTP connection profiling to help optimize page loads
Since the branch point for Aurora is approaching in less than a week, I don’t expect many more probes for Firefox 7.
One problem with doing awesome optimizations that as code changes, they frequently get accidentally undone. I plan to add telemetry to keep tabs on every significant optimization that I do in the future, in addition to retroactively adding it to the past ones. I expect other Mozilla developers to do the same.