[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] About vcpu wakeup and runq tickling in credit
On Thu, 2012-11-15 at 12:18 +0000, George Dunlap wrote: > > So, in the vcpu-affinity case, if pcpu 3 get tickled, when it peeks at > > pcpu 13's runq for work to steal it does not find anything suitable and > > give up, leaving d51v1 in the runq even if there are idle pcpus on which > > it could run, which is already bad. > > In the node-affinity case, pcpu 3 will actually manage in stealing d51v1 > > and running it, even if there are idle pcpus with which it has > > node-affinity, and thus defeating most of the benefits of the whole NUMA > > aware scheduling thing (at least for some workloads). > > Maybe what we should do is do the wake-up based on who is likely to run > on the current cpu: i.e., if "current" is likely to be pre-empted, look > at idlers based on "current"'s mask; if "new" is likely to be put on the > queue, look at idlers based on "new"'s mask. > EhEh, if you check the whole thread, you'll find evidence that I thought this to be a good idea from the very beginning. I've already a patch for that, just let me see if numbers (with and without NUMA scheduling) are aligned with impressions and then I'll send everything together. Thanks for your time, Dario -- <<This happens because I choose it to happen!>> (Raistlin Majere) ----------------------------------------------------------------- Dario Faggioli, Ph.D, http://retis.sssup.it/people/faggioli Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK) Attachment:
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