On Mon, 2013-01-07 at 20:14 +0000, Krishna J wrote: > Hi Alex, > > MSI routing updates aren't currently handled by pci-assign or > > vfio-pci (when using KVM acceleration), which means that trying to > > set interrupt SMP affinity in the guest has no effect unless MSI is > > completely disabled and re-enabled. This series fixes this for both > > device assignment backends using similar schemes. We store the last > > MSIMessage programmed to KVM and do updates to the MSI route when it > > changes. pci-assign takes a little bit of refactoring to make this > > happen cleanly. Thanks, > > I am using the MSI affinity for assigned devices patch 1 to 4. I have > setup the guest such that VCPU0 is pinned to PCPU1, VCPU1 is pinned to > PCPU2, VCPU2 is pinned to PCPU3 and VCPU3 is pinned to PCPU4. I do > this by taskset after the guest boots. I then start generating > interrupts affined to VCPU3. I see all the interrupts directly > delivered to VCPU 3. Now i do the same test but interrupt affined to > VCPU 2. Although the interrupts are delivered to VCPU2 there are lot > of "Rescheduling interrupts" in VCPU 3. I have checked the > smp_affinity and it is updated to VCPU 2. > Wanted to know your feedback on this usecase and what might be the > impact. > CPU0 CPU1 CPU2 CPU3 > 0: 211 0 0 0 IO-APIC-edge timer > 4: 60940 0 0 0 IO-APIC-edge serial > 8: 65 0 0 0 IO-APIC-edge rtc0 > 9: 0 0 0 0 IO-APIC-fasteoi acpi > 40: 0 0 0 0 PCI-MSI-edge virtio1-config > 41: 1910 0 0 0 PCI-MSI-edge virtio1-requests > 42: 0 0 0 0 PCI-MSI-edge virtio0-config > 43: 127 0 0 0 PCI-MSI-edge virtio0-input > 44: 1 0 0 0 PCI-MSI-edge virtio0-output > 45: 1 0 3377 11194 PCI-MSI-edge FPGA_DEV > NMI: 0 0 0 0 Non-maskable interrupts > LOC: 225880 231572 223670 223612 Local timer interrupts > SPU: 0 0 0 0 Spurious interrupts > PMI: 0 0 0 0 Performance monitoring interrupts > IWI: 0 0 0 0 IRQ work interrupts > RTR: 0 0 0 0 APIC ICR read retries > RES: 14 20 21 3398 Rescheduling interrupts-------> Many RES Interrtups!!!!!! > CAL: 0 14 14 16 Function call interrupts > TLB: 0 0 0 0 TLB shootdowns I don't know, but I'll fix the line wrap for anyone else that wants to have a look. The count looks roughly similar to the number of interrupts to VCPU2. Is your application somehow tied to VCPU3? Thanks, Alex -- 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
