[Gretl-devel] Re: MPI and OpenMP (and openblas?)

Am 16.01.2020 um 17:42 schrieb Allin Cottrell: ... Here's what I'm getting with the latest snapshot (slightly edited script attached, remember number of MPI processes is fixed at 2 there), and I'm running this with gretlcli.exe. This is Windows 10 on an i7-8550U (4 cores plus HT; not the same machine when I started this thread - nomen est omen!). * Indeed when the --omp-threads=1 option is used, the setting of OMP_NUM_THREADS makes no difference. This is different to what I had before, but the machine and the snapshot have changed. (The different application doesn't matter.) I will re-check on the other machine later. * But in general the interaction nevertheless seems more complicated, not just a matter of what takes precedence. I'm pasting the results below. thanks sven -------------------- - local setting 2, environment setting going from 1 to 2 dramatically increases the time: GRETL_OLD_SVD is 1 OMP_NUM_THREADS is 1 --omp-threads option is 2 Entering MPI real-time read loop gretlmpi 2020a-git Aktuelle Sitzung: 2020-01-16 19:26 k = 40, elapsed: 1.83464s k = 40, elapsed: 1.94281s GRETL_OLD_SVD is 1 OMP_NUM_THREADS is 2 --omp-threads option is 2 Entering MPI real-time read loop gretlmpi 2020a-git Aktuelle Sitzung: 2020-01-16 19:29 k = 40, elapsed: 10.7115s k = 40, elapsed: 10.8237s - local setting 4, environment going from 1 to 2 even more so: GRETL_OLD_SVD is 1 OMP_NUM_THREADS is 1 --omp-threads option is 4 Entering MPI real-time read loop gretlmpi 2020a-git Aktuelle Sitzung: 2020-01-16 19:27 k = 40, elapsed: 1.82055s k = 40, elapsed: 1.93062s GRETL_OLD_SVD is 1 OMP_NUM_THREADS is 2 --omp-threads option is 4 Entering MPI real-time read loop gretlmpi 2020a-git Aktuelle Sitzung: 2020-01-16 19:28 k = 40, elapsed: 14.9104s k = 40, elapsed: 15.0594s