On Wed, 28 Feb 2024 at 17:36, Ivan Krylov <ikry...@disroot.org> wrote: > > В Tue, 27 Feb 2024 11:14:19 +0000 > Jon Clayden <jon.clay...@gmail.com> пишет: > > > My testing route is to install the packages within the > > 'rocker/r-devel' Docker container, which is Debian-based, then use > > 'time' to evaluate CPU usage. Note that, even though 'RNifti' does not > > use OpenMP, setting OMP_NUM_THREADS changes its CPU usage > > I think that's because rocker/r-devel uses parallel OpenBLAS: > > $ podman run --rm -it docker.io/rocker/r-devel \ > R -q -s -e 'sessionInfo()' | grep -A1 BLAS > BLAS: /usr/lib/x86_64-linux-gnu/openblas-pthread/libblas.so.3 > LAPACK: /usr/lib/x86_64-linux-gnu/openblas-pthread/libopenblasp-r0.3.24.so; > LAPACK version 3.11.0 > > The incoming CRAN check machine either sets the BLAS parallellism to 1 > or uses a non-parallel BLAS. With rocker/r-devel, you can run R with > the environment variable OPENBLAS_NUM_THREADS set to 1. It's been > effective in the past to run R -d gdb and set a breakpoint on > pthread_create before launching the test. (In theory, it may be > required to set a breakpoint on every system call that may be used to > create threads, including various variations of clone(), subject to > variations between operating systems, but pthread_create has been > enough for me so far.) > > With OPENBLAS_NUM_THREADS=1, I'm only seeing OpenMP threads created by > the mmand package during tests for your package tractor.base, and the > latest commit (that temporary disables testing of mmand) doesn't hit > the breakpoint or raise any NOTEs at all.
Very many thanks for testing this, Ivan. I did come across the breakpoint suggestion when searching on this, and tried it, but I ran into some problems with gdb within the container. Your experiments confirm that my yardstick was just misleading me; I will add support for explicitly setting the thread count within mmand, which should give me a longer-term solution. Thanks again, Jon ______________________________________________ R-package-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-package-devel
