On Mon, Aug 02, 2010 at 11:40:23AM +0300, Avi Kivity wrote: > >>Can you do a directed yield? > >We don't have that support yet in Linux scheduler. > > If you think it's useful, it would be good to design it into the > interface, and fall back to ordinary yield if the host doesn't > support it. > > A big advantage of directed yield vs yield is that you conserve > resources within a VM; a simple yield will cause the guest to drop > its share of cpu to other guest. Hmm .. I see possibility of modifying yield to reclaim its "lost" timeslice when its scheduled next as well. Basically remember what timeslice we have given up and add that as its "bonus" when it runs next. That would keep the dynamics of yield donation/reclaim local to the (physical) cpu and IMHO is less complex than dealing with directed yield between tasks located across different physical cpus. That would also address the fairness issue with yield you are pointing at? - vatsa -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
