Open Bug 1458088 Opened Last year Updated Last year
Indicate profiler initialization time properly (especially on Linux where LUL initialization takes a long time)
If you take a look at a profile, such as https://perfht.ml/2Hz3uUR, you can see that there's a long gap with white/blue stripes during the content process initialization that is unprofiled (about 18s in this profile) The tooltip says the buffer was empty, but it probably is caused by something else. We should understand what is causing it and how to reduce that gap.
This time is spent initializing the profiler itself - LUL needs to read libxul.so's unwinding information and convert it into its own format. I agree that the current indicator is very misleading. There's also more dark matter before the indicated main thread start time which we don't indicate at all.
Summary: Understand and reduce the unprofiled gap during content process startup → Indicate profiler initialization time properly (especially on Linux where LUL initialization takes a long time)
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