Re: [Libmesh-users] Questions regarding profiling examples using gprof

[Roy S. <roy...@ic...>]

On Tue, 10 Jul 2018, Boris Boutkov wrote:

> Oh, that's unfortunate. I've uploaded the logs in question to a public google drive folder, they should be available for download at :
> 
> https://drive.google.com/drive/u/1/folders/1-FqKx9FhtSgRAttGVW-4cYNUfzehbpTz

The PerfLog in intro_ex3.log says 97.66% of your time is being spent
in PetscLinearSolver::solve().  What exactly are you trying to profile
here?  There's not even any time spent within PerfLog'ed subroutines
called from within solve(), so you can't be doing a multigrid sweep
here, can you?

If you're not compiling PETSc with -pg that would explain where 97.66%
of your runtime vanished in the gprof output, but I don't see why 99%
of your *call graph* seems to have vanished.  That gprof.log looks as
if you linked a METHOD=prof compiled example against a METHOD=opt
compiled libMesh somehow.
---
Roy