Wu, Feng wrote on 2014-11-13: > > > kvm-owner@xxxxxxxxxxxxxxx wrote on 2014-11-12: >> kvm@xxxxxxxxxxxxxxx; iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; >> linux-kernel@xxxxxxxxxxxxxxx >> Subject: Re: [PATCH 05/13] KVM: Update IRTE according to guest >> interrupt configuration changes >> >> >> >> On 12/11/2014 10:19, Wu, Feng wrote: >>>> You can certainly backport these patches to distros that do not >>>> have VFIO. But upstream we should work on VFIO first. VFIO has >>>> feature parity with legacy device assignment, and adding a new >>>> feature that is not in VFIO would be a bad idea. >>>> >>>> By the way, do you have benchmark results for it? We have not been >>>> able to see any performance improvement for APICv on e.g. netperf. >>> >>> Do you mean benchmark results for APICv itself or VT-d Posted-Interrtups? >> >> Especially for VT-d posted interrupts---but it'd be great to know >> which workloads see the biggest speedup from APICv. > > We have some draft performance data internally, please see the > attached. For VT-d PI, I think we can get the biggest performance gain > if the VCPU is running in non-root mode for most of the time (not in > HLT state), since external interrupt from assigned devices will be delivered by guest directly in this case. > That means we can run some cpu intensive workload in the guests. Have you check that the CPU side posted interrupt is taking effect in w/o VT-D PI case? Per my understanding, the performance gap should be so large if you use CPU side posted interrupt. This data more like the VT-d PI vs non PI(both VT-d and CPU). > > Thanks, > Feng > >> >> Paolo >> -- >> 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 Best regards, Yang ��.n��������+%������w��{.n�����o�^n�r������&��z�ޗ�zf���h���~����������_��+v���)ߣ�
