On Nov 2, 2012, at 9:54 PM, Mohammad Mirzadeh wrote: > Hi, > > To use the new thread model in PETSc, does it suffice to run the code with > the following? > > -threadcomm_type <openmp/pthread> -threadcomm_nthreads <#> > > When I run the code with openmp, only 1 processor/core is active (looking at > top). When using pthread, all cores are active. Am I missing something? OpenMP defaults to binding all threads to a single core if the cpu affinity is not specified explicitly. If you are using GNU OpenMP then you can bind the threads to specific cores using the environment variable GOMP_CPU_AFFINITY http://gcc.gnu.org/onlinedocs/libgomp/GOMP_005fCPU_005fAFFINITY.html If you are some other OpenMP implementation then check its manual to see how to set cpu affinity.
Shri
