RDTSC for good profiling under Linux

Michael B Herf (herf+@cmu.edu)
Sun, 15 Sep 1996 15:35:59 -0400 (EDT)

I'm developing some high-performance graphics applications under Linux,
and I was looking for a good profiler (i.e. better than gprof). I've
learned of the RDTSC and related profiling instructions available on the
Pentium and P-Pro processors. These return cycle-level performance
(including cycles elapsed, cache information, and related items). On
the P-Pro, these instructions can be run in Ring 3, which is really good.

However, on the Pentium, they require Ring 0 execution, which makes
things hard under Linux. Does anyone out there have a kernel module
that allows access to these instructions on the Pentium, or does anyone
more knowledgeable about the kernel want to help me write a set of
system calls to give high-performance profiling information?

thanks,
mike