On Fri, 23 Feb 2001 00:53:02 EST, Havoc Pennington said:
> - you have to rebuild all your libs with -pg (including libc, though
> Red Hat and Debian at least ship a profiling version of that
> prebuilt), but also libX11 and GTK itself, or profile times
> won't include time spent in the libs
This is usually not a big problem, unless your performance issue is a
tight loop 'for (;;) {if (!call_into_libc() ) break;}' type thing...
> - it has limited precision, so anytime you have code that's only
> executed infrequently there's no way to get an accurate profile
Of course, the *first* rule of program optimization is to tune the hot
spots first, so if you don't have an accurate profile because you only
spend 3% of your time in that code, it's not a big thing. Usually, 80%
or more of your time will be spent in 10% of your code - and gprof will
do a good job of telling you were in that 10% you are...
--
Valdis Kletnieks
Operating Systems Analyst
Virginia Tech
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