2015-01-13 00:27+0000, Wu, Feng: > > On 09/01/2015 15:54, Radim Krčmář wrote: > > > There are two points relevant to this patch in new KVM's implementation, > > > ("KVM: x86: amend APIC lowest priority arbitration", > > > https://lkml.org/lkml/2015/1/9/362) > > > > > > 1) lowest priority depends on TPR > > > 2) there is no need for balancing > > > > > > (1) has to be considered with PI as well. > > > > The chipset doesn't support it. :( > > > > > I kept (2) to avoid whining from people building on that behaviour, but > > > lowest priority backed by PI could be transparent without it. > > > > > > Patch below removes the balancing, but I am not sure this is a price we > > > allowed ourselves to pay ... what are your opinions? > > > > I wouldn't mind, but it requires a lot of benchmarking. > > In fact, the real hardware may do lowest priority in round robin way,
Yes, but we won't emulate round robin with PI and I think it is wrong to have backends with significantly different guest-visible behaviors. > the new > hardware even doesn't consider the TPR for lowest priority interrupts > delivery. A bold move ... what hardware was the first to do so? > As discussed with Paolo before, I will submit a patch to support lowest > priority for PI > after this series is merged. Sure, I see only two good solutions though 1) don't optimize lowest priority with PI 2) don't balance lowest priority -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html