Chris@42: Next: Thread safety, Previous: Usage of Multi-threaded FFTW, Up: Multi-threaded FFTW [Contents][Index]
Chris@42:There is a fair amount of overhead involved in synchronizing threads, Chris@42: so the optimal number of threads to use depends upon the size of the Chris@42: transform as well as on the number of processors you have. Chris@42:
Chris@42:As a general rule, you don’t want to use more threads than you have Chris@42: processors. (Using more threads will work, but there will be extra Chris@42: overhead with no benefit.) In fact, if the problem size is too small, Chris@42: you may want to use fewer threads than you have processors. Chris@42:
Chris@42:You will have to experiment with your system to see what level of
Chris@42: parallelization is best for your problem size. Typically, the problem
Chris@42: will have to involve at least a few thousand data points before threads
Chris@42: become beneficial. If you plan with FFTW_PATIENT, it will
Chris@42: automatically disable threads for sizes that don’t benefit from
Chris@42: parallelization.
Chris@42:
Chris@42: