[petsc-users] petsc and goto blas

[Barry Smith]

On Aug 29, 2011, at 5:49 PM, David Fuentes wrote:

> Is there any reason why petsc compiled to link with goto blas shared
> libraries would not run multi-threaded by default ?

   We don't do anything to prevent it from using multi-threaded. Te first thing I would suggest is make sure it truly is linking and running against the threaded goblas and something else doesn't get in between.

   Barry

> 
> I've set (OMP/GOTO)_NUM_THREADS=8
> 
> but when I call dgemm from PETSc I can't seem to get it to run on
> multiple cores (<= 100% cpu usage from top).
> I checked and the test routines installed with goto library build
> called w/o petsc runs multi-threaded (~600% cpu usage on top).
> 
> 
> I'm calling MatMatMult with dense matrices from petsc4py.
> 
> from petsc4py import PETSc
> import numpy
> n = 10000
> J1 = PETSc.Mat().createDense([n, n], array=numpy.random.rand(n,n),
> comm=PETSc.COMM_WORLD)
> J1.assemblyBegin();J1.assemblyEnd()
> J2 = PETSc.Mat().createDense([n, n],
> array=numpy.random.rand(n,n),comm=PETSc.COMM_WORLD)
> J2.assemblyBegin(); J2.assemblyEnd()
> X = J1.matMult(J2)