I can't get good performance with ippsFir_32f() past the point where it starts using FFTs internally (CORRECTION: that is, past the point where FFTs start getting processed in parallel at order 13). I get about 80% wait time and it's all caused by _kmp_launch_worker threads.
- kmp_set_blocksize(200) via dll import
Yet I still see multiple kmp threads in Vtune and overall cpu usage is about 75% between 4 cores. What could I be doing wrong here?