On Thu, 28 May 2020 at 10:04, Susi Lehtola <jussilehtola@xxxxxxxxxxxxxxxxx> wrote: > > The correct case is to use the OpenMP flavor of OpenBLAS to avoid these > issues. If you use the OpenMP library in a sequential program, the BLAS > runs in parallel, and if you use the OpenMP library in an OpenMP > parallel program the BLAS runs either sequentally (within > already-parallel regions) or in parallel (within sequential regions). The problem arised in a threaded algorithm. Reference BLAS, as well as serial MKL and Atlas are thread-safe. I did recommend openblas-openmp to the user that reported the issue with an R package, but not everybody knows or understands why there are so many versions. > > So it's clear that things are failing out there, and USE_LOCKING=1 is > > a sensible default that we should apply. I didn't find though what's > > the performance penalty of setting such a flag. > > I've toggled USE_LOCKING=1 in openblas-0.3.9-3. Great, thanks! > > But if that's noticeable, then this is another argument in favour of > > providing a proper mechanism for the user to switch the > > implementation, as e.g. Debian does. > > Debian's mechanism for switching the implementations is improper, due > to reasons already discussed on this list. I'm not proposing Debian's mechanism. I just say that Debian has *a* mechanism, and for that reason some people prefer Debian. But there may be a better way: see [1]. [1] https://lists.fedoraproject.org/archives/list/devel@xxxxxxxxxxxxxxxxxxxxxxx/message/DEMALSR4HB7IQ3JIUN4OMJXUDWY4HZ26/ -- Iñaki Úcar _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@xxxxxxxxxxxxxxxxxxxxxxx
