Re: [Xen-devel] [PATCH 3/5] xen: sched-null: support soft-affinity

[George Dunlap <George.Dunlap@xxxxxxxxxxxxx>]

On Thu, Jun 29, 2017 at 1:56 PM, Dario Faggioli
<dario.faggioli@xxxxxxxxxx> wrote:
> The null scheduler does not really use hard-affinity for
> scheduling, it uses it for 'placement', i.e., for deciding
> to what pCPU to statically assign a vCPU.
>
> Let's use soft-affinity in the same way, of course with the
> difference that, if there's no free pCPU within the vCPU's
> soft-affinity, we go checking the hard-affinity, instead of
> putting the vCPU in the waitqueue.
>
> This does has no impact on the scheduling overhead, because
> soft-affinity is only considered in cold-path (like when a
> vCPU joins the scheduler for the first time, or is manually
> moved between pCPUs by the user).
>
> Signed-off-by: Dario Faggioli <dario.faggioli@xxxxxxxxxx>

Reviewed-by: George Dunlap <george.dunlap@xxxxxxxxxx>

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