Hi Guys, there have a issue about smp_affinity cannot work correctly on guest os when PCI passthrough device using msi/msi-x with KVM. My reason: pcpu will occur a lot of ipi interrupt to find the vcpu to handle the irq. so the guest os will VM_EXIT frequelty. right? if smp_affinity can work correctly on guest os, the best way is that the vcpu handle the irq is cputune at the pcpu which handle the kvm:pci-bus irq on the host.but unfortunly, i find that smp_affinity can not work correctly on guest os when msi/msi-x. how to reproduce: 1: passthrough a netcard (Brodcom BCM5716S) to the guest os 2: ifup the netcard, the card will use msi-x interrupt default, and close the irqbalance service 3: echo 4 > cat /proc/irq/NETCARDIRQ/smp_affinity, so we assume the vcpu2 handle the irq. 4: we have set <vcpupin vcpu='2' cpuset='1'/> and set the irq kvm:pci-bus to the pcpu1 on the host. we think this configure will reduce the ipi interrupt when inject interrupt to the guest os. but this irq is not only handle on vcpu2. maybe it is not our expect。 YiLi Thanks -- 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
