Messages in this thread | | | Date | Tue, 11 Oct 2011 20:38:04 +0200 | From | "Michael S. Tsirkin" <> | Subject | [PATCH RFC 0/2] kvm: set irq affinity for assigned devices |
| |
To forward an interrupt to a vcpu that runs on a host cpu different from the current one, we need an ipi which likely will cost us as much as delivering the interrupt directly to that cpu would.
So it seems to make sense to set irq affinity hint to point there, irq balancer can then take this into accound and balance interrupts accordingly.
This is what this patchset does. Note: it might make sense to optimize the gsi lookups here for the msi case, using rcu, the way we did for eventfd. But that's a subject for another patch.
Warning: compiled only.
Any early comments / flames?
Thanks,
-- MST
Michael S. Tsirkin (2): kvm: pass host irq number to set irq calls kvm: set affinity hint for assigned device msi
arch/x86/kvm/i8254.c | 4 ++-- arch/x86/kvm/lapic.c | 2 +- arch/x86/kvm/x86.c | 2 +- include/linux/kvm_host.h | 7 ++++--- virt/kvm/assigned-dev.c | 17 ++++++++++------- virt/kvm/eventfd.c | 7 ++++--- virt/kvm/ioapic.c | 2 +- virt/kvm/ioapic.h | 2 +- virt/kvm/irq_comm.c | 35 +++++++++++++++++++++++++++-------- 9 files changed, 51 insertions(+), 27 deletions(-)
-- 1.7.5.53.gc233e
| |