topic Fast poisson solver threading control in Intel® oneAPI Math Kernel Library

Fast poisson solver threading control

Nafees_B_ — Wed, 27 Apr 2016 09:08:27 GMT

I'm trying to control the number of threads used by the fast poisson solver *_Helmholtz_3D. The code is compiled with -tbb and -mkl, and I'm using tbb::task_scheduler_init() function to control the thread count. However, this solver seem to be multithreaded regardless of the number of threads I tell tbb to use. How can I control this?

MKL Version 11.3.2
ICPC Version 2016.2.062

Thanks!

Hi Nafees,

Ying_H_Intel — Fri, 06 May 2016 03:14:35 GMT

Hi Nafees,

As I understand, in your case -tbb and -mkl, there are two kind of thread methods:

tbb,

and

OpenMP (-mkl, by default mkl routine will use OpenMP thread)

tbb::task_scheduler_init() function to control the thread count. but it can't control the thread within MKL routine.

How about you to try

>export KMP_AFFINITY= verbose

>export OMP_NUM_THREADS=1 (Linux)

or set OMP_NUM_THREADS=1 (windows)

and see if there is any change.

Best Regards,

Ying