FFT performance issue

c__vishnu — Sat, 05 May 2018 06:41:17 GMT

I am evaluating the MKL library for the new project. While computing the FFT, I could see that performance of the FFT (in terms of GFLOP/s) reduces if the threads are in different socket ( using thread affinity). The test was carried out in Intel(R) Xeon(R) CPU E5-2650 processor and compiler is gcc. Please let me know the reason.

Hi Vishnu,

Ying_H_Intel — Tue, 08 May 2018 06:28:18 GMT

Hi Vishnu,

The first thought , it is threading and memory localization problem. The current CPU and memory structure expected the threads have access to their data as near as possible. It may not only about MKL FFT, it should be any mulitithreaded computation task. How do store the FFT data and affinity the thread to different sockets?

And MKL developer guide https://software.intel.com/en-us/mkl-linux-developer-guide-managing-multi-core-performance have some discussed about how to get best performance by thread affinity. for your reference.

You can obtain best performance on systems with multi-core processors by requiring that threads do not migrate from core to core.

Best Regards,

Ying

topic FFT performance issue in Intel® oneAPI Math Kernel Library

FFT performance issue

Hi Vishnu,