How to profile www/firefox to find out the reason for high CPU usage

[Arto Pekkanen]

Hello.

I've noticed that there is a constant problem with high CPU usage with
www/firefox on my laptop (Thinkpad T430, dual-core i5, 8 Gt RAM). The
high CPU usage is primarily on the firefox process itself.

Firefox is installed from FreeBSD-latest repository, and all the related
components are also vanilla, so the should be no margin for user error.

I can reproduce the high CPU usage just by opening a couple dozen tabs
and then letting Firefox run for a few hours.

In order to fix this high CPU usage, I would need to figure out how much
time gets spent in which components of Firefox, ie. I need to profile
Firefox.

However, I lack knowledge on how to do this. The "official"
documentation only mentions installing the profiler plugin (.xpi), but
the plugin does NOT work on FreeBSD out of box. It doesn't work even if
I build Firefox with profiling support enabled.

So ... how can profile Firefox, any ideas? How do you guys do it? Is
there some complicated set of utilities I need to use?

-- 
Arto Pekkanen

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