GMON_OUT_PREFIX

[rkufrin@ncsa.uiuc.edu (Rick Kufrin)]

Greg,

This seems to work great - I just tried it out on a single-processor
program on Titan, also single and MPI run on Platinum.

I'm not sure if this is documented anywhere, but recent versions
of glibc support the environment variable GMON_OUT_PREFIX, which
causes the resulting files to be named something other than gmon.out,
and instead names them according to the process ID:

	$GMON_OUT_PREFIX.<pid>

I think this is helpful in the case of MPI processes so they don't
overwrite each other's profile.  Another thing that seems to
work is to generate a summary from multiple profiles, e.g.,

	gprof -s a.out $GMON_OUT_PREFIX.*
	gprof a.out gmon.sum > summary-profile

Rick

> ============ Gregory Bauer's message of May 20,  4:28pm ================
> I met with Dan Lapine and he copied the patched version of 
> gcrt1.o to /usr/lib on titan. This file is loaded during compile/link 
> time.
> 
> To profile using efc/ecc, use '-qp -g' and which ever optimization level, 
> '-O2' for example. (Yes, you need to use the -g but since it also allows 
> optimization, it shouldn't be a hinderance.)
> 
> For gcc, use the usual '-pg'. 
> 
> If you run into problems, let me know.
> 
> -Greg  
> ============ End of Gregory Bauer's message of May 20,  4:28pm =========