Re: [PATCH] syscall interface for cpu affinity

Robert Love (rml@tech9.net)
10 Mar 2002 15:53:38 -0500


On Sun, 2002-03-10 at 15:29, Andreas Jaeger wrote:

> Please add the procinterface also! I've found it today (for 2.4.18)
> and it's much easier to use with existing programs.

I agree and I really like the proc-interface. There is something uber
cool about:

cat 1 > /proc/pid/affinity

I have a patch for 2.5.6 for proc-based affinity interface here:

http://www.kernel.org/pub/linux/kernel/people/rml/cpu-affinity/v2.5/cpu-affinity-proc-rml-2.5.6-1.patch

I suspect, however, that despite both patches being small we really only
want to pick and standardize on one. The syscall interface has two main
things going for it against a proc-based implementation: it is faster
and /proc may not be mounted. The masses have spoken on this issue.

Note you can use the syscall interface with existing programs, too.
Just write a program to take in a pid and mask and call
sched_set_affinity.

> Please add it for all archs - this is not only interesting for x86,

I'll send Linus the patch for other arches if/when he accepts this patch
- I have no problem with that.

Robert Love

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