topic Multi-threaded performance on MKL on highly loaded CPUs.... in Intel® oneAPI Math Kernel Library

Multi-threaded performance on MKL on highly loaded CPUs....

Tony_Garratt — Thu, 22 Apr 2010 17:05:03 GMT

Suppose I have dual core machine and I am using MKL in my application. I have not set MKL_NUM_THREADS, so my MKL routines will try to use both cores. Suppose though that another application is hammering both my cores; will MKL release that both cores are fully utilised and will back off and use only 1?

This is not stated anywhere in the documentation (unless I missed it), so some clarification would be helpful please.

thanks!
Tony

Multi-threaded performance on MKL on highly loaded CPUs....

TimP — Thu, 22 Apr 2010 18:13:48 GMT

No, I don't expect MKL to perform any checks on which cores are busy. When you don't set KMP_AFFINITY, you leave scheduling to the OS. As you hinted, you can cut back to 1 thread by setting MKL_NUM_THREADS or OMP_NUM_THREADS.

Multi-threaded performance on MKL on highly loaded CPUs....

Gennady_F_Intel — Fri, 23 Apr 2010 04:30:02 GMT

That's right. MKL doesn't checkwhether the processors are busy or in any application or not.

--Gennady