2020-05-19 18:20:18 +02:00
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title = "Linux: HOWTO get the number of CPUs"
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date = 2013-11-13T12:13:04+00:00
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2023-10-26 11:53:38 +02:00
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[taxonomies]
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tags = ["linux", "fedora"]
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2020-05-19 18:20:18 +02:00
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```console
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$ getconf _NPROCESSORS_ONLN
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```
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returns the number of CPUs online.
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<!-- more -->
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Internally it is parsing
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`/sys/devices/system/cpu/online`, which can have the contents: `0-3,5,7-9`.
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Better let getconf [do all the counting for you](https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/getsysstats.c#l127).
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This is very useful, if you want to optimize the number of threads.
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