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Re: [Xen-devel] [PATCH RESEND 05/12] xen: numa-sched: make space for per-vcpu node-affinity

On 11/05/2013 03:23 PM, Jan Beulich wrote:
On 05.11.13 at 16:11, George Dunlap <george.dunlap@xxxxxxxxxxxxx> wrote:
Or, we could internally change the names to "cpu_hard_affinity" and
"cpu_soft_affinity", since that's effectively what the scheduler will
do.  It's possible someone might want to set soft affinities for some
other reason besides NUMA performance.

I like that.

A potential problem with that is the "auto domain numa" thing. In this patch, if the domain numa affinity is not set but vcpu numa affinity is, the domain numa affinity (which will be used to allocate memory for the domain) will be set based on the vcpu numa affinity. That seems like a useful feature (though perhaps it's starting to violate the "policy should be in the tools" principle). If we change this to just "hard affinity" and "soft affinity", we'll lose the natural logical connection there. It might have impacts on how we end up doing vNUMA as well. So I'm a bit torn ATM.

Dario, any thoughts?


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