Why you should use `nproc` and not grep /proc/cpuinfo | Lobsters

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Why you should use `nproc` and not grep /proc/cpuinfo linux flamingspork.com
via inactive-user 1 month ago | cached | 1 comment

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junot 1 month ago | link
After reading this I wondered how nproc was implemented. It seems to be getting a cpu affinity mask for the process and passing that through popcnt to get the processor count.
- sched_getaffinity() doc: https://linux.die.net/man/2/sched_getaffinity
- sched_getaffinity() call: https://git.savannah.gnu.org/cgit/gnulib.git/tree/lib/nproc.c?id=af00772324533eec56696f3e0ee23136323ea5f6#n127
- popcnt (via CPU_COUNT): https://sourceware.org/git/?p=glibc.git;a=blob;f=posix/sched_cpucount.c;h=4242b69eec8899d67a8d6c2eaf4006d11785d138;hb=HEAD#l33