Some (small) c++ compilation profiling data (oprofile)

[Will Cohen <wcohen at redhat dot com>]

Profiling and characterization of gcc by oprofile would be very useful.

The cvs version of oprofile has a "--reverse" option for oprofpp, which 
lists things from largest to smallest. This will put the largest samples 
right after the information about what was being sampled, so the most 
interesting information is together. It would be useful to include that 
  header information about what is being sampled and what the rate is.
One of the strengths of oprofile is it can measure things other than 
time, e.g. cache misses and branch mispredictions. Having the header 
information with the measurements will avoid confusion.

What environment (hardware and software) did you use to take these 
measurements? Ideally, someone else should be able to reproduce and 
verify the result.  GCC is a moving target, the cvs tag used to check 
out the code should be included. Is the bootstrapped compiler being used 
for the tests? If just the stage1 compiler is being used, the compiler 
used to build the GCC being profiled can influence the measurements.

You might want to get copies of the Intel software optimization manuals 
to get an idea of what other metrics to measure.

Pentium III software optimization manual:

http://www.intel.com/design/pentiumii/manuals/245127.htm

Right now oprofile only provide RTC sampling for Pentium 4, but here is 
link to the web page for the Pentium 4 software optimization manual:

http://www.intel.com/design/pentium4/manuals/248966.htm

-Will


-- 
Will Cohen, GCC Engineer