Hi, just noticed this and thought I might just jump in. :) On 20/04/17 16:00, Paolo Bonzini wrote: > Adding Rik. > > Paolo > > On 20/04/2017 15:32, Gonglei (Arei) wrote: > > Hi all, > > > > Currently, KVM do the CPU resource reservation by the cgroup mechanism > > which can't do entire accurate separation because the capacity of the Linux > > scheduler. Take the public cloud as an example, some customers rent one vm > > with 8 CPUs paid by enough money, they want to get enough response > > speed on CPU scheduling. So we (the cloud platform providers ) reserve 1GHz > > CPU resources by cgroup for those VM's vcpu/pcpu. > > > > But the actual effects can't meet those requirements because the cgroup is > > limiting share usage of other processes in order to attach the reservation proportion, > > but the scheduler can't assure that. This mechanism is different with Xen, > > We can directly change the CPU weight on Xen hypervisor so that we can > > get entire accurate control on CPU resources based on accurate capacity (upper limit), > > share (weight) and reservation. > > > > So my question is do we have a good method to do CPU reservation in KVM? > > > > Thanks, > > -Gonglei Not entirely sure what your particular requirements are Gonglei, but you might be interested to know that there has been research work [1,2,3, just to name a few] that used a mainline real-time scheduling policy (SCHED_DEADLINE) to provide Qos support to virtual machines (KVM). I won't enter in too much detail, but the basic idea is to use reservation based scheduling mechanisms to enforce temporal isolation and guaranteed CPU bandwidth to VM's vcpu(s). I'm Cc-ing Tommaso, Luca and Carlo, whom can provide more information as needed. Best, - Juri [1] - http://retis.sssup.it/~nino/publication/rtlws14sdnnfs.pdf [2] - http://retis.sssup.it/~tommaso/publications/VHPC-2010.pdf [3] - http://retis.sssup.it/~tommaso/publications/RTSOAA-2009-RTV.pdf Skimming through Tommaso and Luca publications might be interesting as well. I'm pretty sure I missed the most importants papers. :) http://retis.sssup.it/~tommaso/eng/publications.html https://scholar.google.co.uk/citations?user=C3a6glEAAAAJ&hl=en -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
