В Thu, 7 Oct 2021 21:58:08 -0400 (EDT) Vladimir Dergachev <volo...@mindspring.com> пишет:
> * My understanding from reading documentation and source code is > that there is no dedicated support in R yet, but there are packages > that use multithreading. Are there any plans for multithreading > support in future R versions ? Shared memory multithreading is hard to get right in a memory-safe language (e.g. R), but there's the parallel package, which is a part of base R, which offers process-based parallelism and may run your code on multiple machines at the same time. There's no communication _between_ these machines, though. (But I think there's an MPI package on CRAN.) > * pthread or openmp ? I am particularly concerned about > interaction with other packages. I have seen that using pthread and > openmp libraries simultaneously can result in incorrectly pinned > threads. pthreads-based code could be harder to run on Windows (which is a first-class platform for R, expected to be supported by most packages). OpenMP should be cross-platform, but Apple compilers are sometimes lacking; the latest Apple likely has been solved since I've heard about it. If your problem can be made embarrassingly parallel, you're welcome to use the parallel package. > * control of maximum number of threads. One can default to openmp > environment variable, but these might vary between openmp > implementations. Moreover, CRAN-facing tests aren't allowed to consume more than 200% CPU, so it's a good idea to leave the number of workers in control of the user. According to a reference guide I got from openmp.org, OpenMP implementations are expected to understand omp_set_num_threads() and the OMP_NUM_THREADS environment variable. -- Best regards, Ivan ______________________________________________ R-package-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-package-devel
