Update: fpm_backend with dynamic openmp scheduling #345
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awvwgk
approved these changes
Jan 29, 2021
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I noticed the parallel compilation time for my stdlib-fpm package was quite poor (on 4 threads) and realised the default static scheduling of threads was causing poor utilisation since compilation times can vary significantly between individual targets. (This is less of a problem for higher core counts)
This PR makes dynamic scheduling explicit when using OpenMP for parallel compilation which gives much better utilisation (2x improvement for stdlib-fpm) and avoids implementation-dependent choice of scheduling. We have no pressing need for static scheduling and the overhead for dynamic scheduling appears to be small compared to the time for compilation.