[Gretl-devel] Re: mols() and multithreading

Am 28.01.2020 um 07:34 schrieb Marcin Błażejowski: > On 17.01.2020 12:13, Sven Schreiber wrote: >> I varied the environment variables OMP_NUM_THREADS and >> OPENBLAS_NUM_THREADS: >> >> OMP...            OPENBLAS...       best of 3 runs >> <unset/default>   <unset/default>   6.4 s >> 4                 4                 6.4 s >> 4                 1                 6.4 s >> 1                 4                 2.9 s >> 1                 1                 2.9 s >> >> > Hi Sven again, > > my machine is still: 4 Hyper-Threaded Core i7-8550U CPU @ 1.80GHz, but > this time we use new Allin's compiler/linker settings for Debian-like > system to force linking against OpenBLAS (0.3.7 + OpenMP). > > My results: > > OMP...            OPENBLAS...       best of 3 runs > <unset/default>   <unset/default>   2.067 > 4                 4                2.83 > 4                 1                2.83 > 1                 4                2.81 > 1                 1                2.80 > ------------------------------------------ > 8                 8                2.86 > 8                 4                2.81 > 4                 8                2.86 > 8                 1                2.81 > 1                 8                2.87 > ------------------------------------------ > Thanks Marcin, that's looking very good! I guess you're using current git for that?

But openblas alone doesn't explain the equality of the 4-thread and the single-thread outcome, at least comparing to the Windows results. Or did you compile openblas yourself? (Perhaps with a different dgemm threshold?)