Re: numactl using it's own affinity to determine CPU set

Hi everyone,

On Mon, 22 Oct 2012, Jon Stanley wrote:
> On Mon, Oct 22, 2012 at 3:41 PM, Andi Kleen <[email protected]> wrote:
> > That was done intentional at some point to handle cpusets.
> > numactl 1.0 or so didn't have that problem.
> 
> I'll happily admit to not being an expert here :)

I've added new interface for parsing cpusets/nodesets with _all() suffix
in 2.0.8-rc5 libnuma, but numactl utility still uses old ones with cpuset
awareness. I didn't want to dig into some libnuma internals and change
behaviour of dependent utils in such way.

> 
> However, I thought that the concept of cpusets was that if you
> attempted to set affinity outside of your cpuset, that would silently
> fail. I assume that the reason that libnuma didn't want to set outside
> of it's own affinity mask is to avoid such a silent failure?
> 
> Also, I question the Real World(TM) prevalence of cpusets.
> 
> > However it's unclear if it's really bug.
> 
> Not sure if I'd call it a bug since it was intentional, but sure would
> call it an unexpected change in behavior :)

I like the idea of some overriding option proposed by Andi.

btw, Cliff, can you remember what was the reason for this change in some
version after 1.0?

Petr