Prevent accidental increase of the thread count inside a parallel region - #5949
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martin-frbg wants to merge 1 commit into
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Prevent accidental increase of the thread count inside a parallel region#5949martin-frbg wants to merge 1 commit into
martin-frbg wants to merge 1 commit into
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I added a test case in #5950 that would hopefully catch a future regression in case you wanted to port something like it over to this PR |
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Thanks - now you've got me worrying if my patch could be too simple. But as far as I'm aware, trying to run more than one thread when already inside a parallel region is invoking undefined behavior at least with older OpenMP versions (and I think even with the latest one). And the openblas_num_threads_local is unfinished and unrelated to OpenMP. |
Contributor
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I don't think nested parallel regions (at least with the current standard) is undefined behavior. If it was then the omp_set_max_active_levels API doesn't make much sense https://www.openmp.org/spec-html/5.0/openmpsu125.html |
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fixes #5947