Messages in this thread | | | Date | Mon, 11 May 2015 13:45:15 +0200 | From | Paolo Bonzini <> | Subject | Re: [PATCH] kvm: irqchip: Break up high order allocations of kvm_irq_routing_table |
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On 11/05/2015 13:25, Joerg Roedel wrote: >> > It probably doesn't matter much indeed, but can you time the difference? >> > kvm_set_irq_routing is not too frequent, but happens enough often that >> > we had to use a separate SRCU instance just to speed it up (see commit >> > 719d93cd5f5, kvm/irqchip: Speed up KVM_SET_GSI_ROUTING, 2014-01-16). > The results vary a lot, but what I can say for sure is that the > kvm_set_irq_routing function takes at least twice as long (~10.000 vs > ~22.000 cycles) as before on my AMD Kaveri machine (maximum was between > 3-4 times as long). > > On the other side this function is only called 2 times at boot in my > test, so I couldn't detect a noticable effect on the overall boot time > of the guest (37 disks were attached).
Christian, can you test this?
Paolo
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