On Fri, 2017-06-23 at 11:02 +0100, Anshul Makkar wrote: > On 16/06/2017 15:13, Dario Faggioli wrote: > > diff --git a/xen/common/sched_credit.c b/xen/common/sched_credit.c > > index efdf6bf..53773df 100644 > > --- a/xen/common/sched_credit.c > > +++ b/xen/common/sched_credit.c > > @@ -136,27 +136,6 @@ > > * > > + * Hard affinity balancing is always necessary and must never be > > skipped. > > + * But soft affinity need only be considered when it has a > > functionally > > + * different effect than other constraints (such as hard affinity, > > cpus > > + * online, or cpupools). > > + * > > + * Soft affinity only needs to be considered if: > > + * * The cpus in the cpupool are not a subset of soft affinity > > do you mean cpus in a cpupool are not in a subset of the soft > affinity > of a vcpu which is a runnable state ? > Err... not sure. It's probably the same. IAC, what this means is that, if a vcpu is in cpupool C, and the cpus of cpupool C are 1,2,3 _and_ the soft affinity of the vcpu is 0,1,2,3,4,5 then, it does not make sense to check soft-affinity.
In fact, the vcpu will only execute on either 1,2 or 3, which are all part of its soft-affinity anyway. And it should be exactly that the cpupool is *a* *subset* of the soft- affinity. In fact, if cpupool is 1,2,3 and soft-affinity is 0,1,3,4,5 then it _does_ make sense to check soft affinity,, to try not to run the vcpu on 2. Hope this clarify things. Regards, Dario -- <<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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