> -----Original Message----- > From: Paolo Bonzini [mailto:paolo.bonzini@xxxxxxxxx] On Behalf Of Paolo > Bonzini > Sent: Friday, December 19, 2014 8:01 PM > To: Zhang, Yang Z; Wu, Feng; Paolo Bonzini; KVM list > Cc: iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx > Subject: Re: [v3 25/26] KVM: Suppress posted-interrupt when 'SN' is set > > > > On 19/12/2014 06:25, Zhang, Yang Z wrote: > > I see your point. But from performance point, if we can schedule the > > vCPU to another PCPU to handle the interrupt, it would helpful. But I > > remember current KVM will not schedule the vCPU in run queue (even > > though it got preempted) to another pCPU to run(Am I right?). So it > > may hard to do it. > > Yes. If the vCPU is in the run queue, it means it exhausted its > quantum. As Feng said, the scheduler can decide to migrate it to > another pCPU, or it can decide to leave it runnable but not start it. > KVM doesn't try to force the scheduler one way or the other. > > If the vCPU is I/O bound, it will not exhaust its quantum and will not > be preempted. It will block, and the wakeup vector will restart it. > > I don't think urgent notifications are interesting. If you want to do > real time work, pin the vCPU to a physical CPU, and isolate the pCPU > with isolcpus. Then the vCPU will always be running. > > Paolo I agree, thanks Paolo! Thanks, Feng -- 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
