My programme run on 2 CPU workstation,at the same time using Hyper-Threading Technology.So OMP_get_processors()=4; I try running programme on two occasions. one is a 2 CPU workstation without Hyper-Threading Technology (OMP_get_processors()=2), the other is the same 2 CPU workstation at the same time using Hyper-Threading Technology (OMP_get_processors()=4), I found the latter programme is quicker that the former under OMP. For latter, the whole programme use 140ms without OMP,when I use OMP , I only see a little improvement, it use 109ms. I expected it should use 50 or 60ms. So I don't know why.
I try replace nspcfft() with other function,I could see a better improvement as I expected, 3 sections with OMP could save 2/3 time than no using OMP.I don't know what's wrong with my original programme.