Re: [PATCH] proc-based cpu affinity user interface

Robert Love (rml@tech9.net)
26 Nov 2001 23:14:23 -0500


On Mon, 2001-11-26 at 22:52, Davide Libenzi wrote:
> As I said in reply to Ingo patch, it'd be better to expose "number" cpu
> masks not "logical" ( like cpus_allowed ).
> In this way the users can use 0..N-1 ( N == number of cpus phisically
> available ) w/out having to know the internal mapping between logical and
> number ids.

Do you mean you don't like using a bitmask ?

00000001 = first CPU, its not logical, its physical.

Plus, how do you intend to set multiple non-contiguous CPUs? A fraction
of them? With only a 32-bit value?

Note also that my patch understands the underlying CPU nature, such that
"echo 0000ffff > /proc/123/affinity" will only affine task 123 to your
first 2 CPUs if you only have two. Thus, "cat /proc/123/affinity" will
return "00000003".

Robert Love

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