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

On mar, 2013-11-05 at 16:56 +0000, George Dunlap wrote:
> [Coming back after going through the whole series]
> This is basically the main architectural question that needs to be 
> sorted out with the series: Do we bake in that the "soft affinity" is 
> specifically for NUMA-ness, or not?
Damn... I was really hoping to be almost done with this series!
Unfortunately, this point you're raising is a very good one and, even
more unfortunately, I like the way in which you propose to solve it, so
I've got to re-implement this thing, or --I'm sure of that-- I won't be
able to get any sleep at night for months! :-P :-P :-P

> The patch the way it is does make this connection, and that has several 
> implications:
> * There is no more concept of a separate "domain numa affinity" (Patch 
> 06); the domain numa affinity is just a pre-calculated union of the vcpu 
> affinities.
> * The interface to this "soft affinity" is a bitmask of numa nodes, not 
> a bitmask of cpus.
> If we're OK with that direction, then I think this patch series looks 
> pretty good.
We're not... As said, now that you put it this way, it really sound so
much wrong, that I have to fix it! :-)

> Release-wise, I think as long as we're OK with libxl providing a 
> "set_vcpu_numa_affinity", then we can always come back and change the 
> implementation later if we want to maintain that distinction internally.
That's true too. Let's see how far and how quick can I get to
implementing what you propose and then decide. BTW, if I can ask (and
sorry if it's my fault for having missed it), what's the updated release

Thanks and Regards,

<<This happens because I choose it to happen!>> (Raistlin Majere)
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)

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