Message ID | CAJfdMYAjHFVVAzekDA_L=q+xYvPeM_mcAU5okgLJedtts0P2jQ@mail.gmail.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Maybe the patch have a risk to break the process of lapic.just avoid a IPI between the cpu core asap. Thanks YiLi 2012/12/4 yi li <yilikernel@gmail.com>: > The cpu inject the interrupt to vcpu which vcpu->cpu is the same as it. > And it maybe avoid a IPI between the cpu core. > > Signed-off-by: Yi Li <yilikernel@gmail.com> > > --- linux/virt/kvm/irq_comm.c 2012-12-04 10:14:57.711024619 +0800 > +++ linux/virt/kvm/irq_comm.c 2012-12-04 11:01:27.728859597 +0800 > @@ -64,9 +64,10 @@ inline static bool kvm_is_dm_lowest_prio > int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src, > struct kvm_lapic_irq *irq) > { > - int i, r = -1; > + int i, cpu, r = -1; > struct kvm_vcpu *vcpu, *lowest = NULL; > > + cpu = get_cpu(); > if (irq->dest_mode == 0 && irq->dest_id == 0xff && > kvm_is_dm_lowest_prio(irq)) { > printk(KERN_INFO "kvm: apic: phys broadcast and lowest prio\n"); > @@ -89,13 +90,17 @@ int kvm_irq_delivery_to_apic(struct kvm > r = 0; > r += kvm_apic_set_irq(vcpu, irq); > } else if (kvm_lapic_enabled(vcpu)) { > - if (!lowest) > + if(vcpu->cpu == cpu) { > + lowest = vcpu; > + break; > + } > + else if (!lowest) > lowest = vcpu; > else if (kvm_apic_compare_prio(vcpu, lowest) < 0) > lowest = vcpu; > } > } > - > + put_cpu(); > if (lowest) > r = kvm_apic_set_irq(lowest, irq); > > > YiLi > Thanks -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Dec 04, 2012 at 11:08:41AM +0800, yi li wrote: > The cpu inject the interrupt to vcpu which vcpu->cpu is the same as it. > And it maybe avoid a IPI between the cpu core. > How often this happens in your testing? Regardless we cannot disable preemption while iterating over all vcpus. Low latency people will kill us. > Signed-off-by: Yi Li <yilikernel@gmail.com> > > --- linux/virt/kvm/irq_comm.c 2012-12-04 10:14:57.711024619 +0800 > +++ linux/virt/kvm/irq_comm.c 2012-12-04 11:01:27.728859597 +0800 > @@ -64,9 +64,10 @@ inline static bool kvm_is_dm_lowest_prio > int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src, > struct kvm_lapic_irq *irq) > { > - int i, r = -1; > + int i, cpu, r = -1; > struct kvm_vcpu *vcpu, *lowest = NULL; > > + cpu = get_cpu(); > if (irq->dest_mode == 0 && irq->dest_id == 0xff && > kvm_is_dm_lowest_prio(irq)) { > printk(KERN_INFO "kvm: apic: phys broadcast and lowest prio\n"); > @@ -89,13 +90,17 @@ int kvm_irq_delivery_to_apic(struct kvm > r = 0; > r += kvm_apic_set_irq(vcpu, irq); > } else if (kvm_lapic_enabled(vcpu)) { > - if (!lowest) > + if(vcpu->cpu == cpu) { > + lowest = vcpu; > + break; > + } > + else if (!lowest) > lowest = vcpu; > else if (kvm_apic_compare_prio(vcpu, lowest) < 0) > lowest = vcpu; > } > } > - > + put_cpu(); > if (lowest) > r = kvm_apic_set_irq(lowest, irq); > > > YiLi > Thanks > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
My test: 1:guest os has 2 vcpu and has a virtio netcard, also host os just has 2 cpu cores, and do not do any smp_affinity 2:using the jprobe to probe the function kvm_vcpu_kick on the host ....... static int i=0; int jkvm_vcpu_kick(struct kvm_vcpu *vcpu) { int cpu = vcpu->cpu; printk("vcpu->cpu is %d\n",cpu); printk("the pcpu to handle the inject irq is %d\n", smp_processor_id()); if(cpu != smp_processor_id()) { i = i+ 1; } printk("the ipi sum is %d\n", i); /* Always end with a call to jprobe_return(). */ jprobe_return(); return 0; } .......................... run the command ping the guestos virtio netcard 3: test result, sometimes, it is very bad, you see blow, there has 14 ipi (64-50) Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.009937] vcpu->cpu is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.009940] the pcpu to handle the inject irq is 0 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.009942] the ipi sum is 50 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010008] vcpu->cpu is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010011] the pcpu to handle the inject irq is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010013] the ipi sum is 50 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010051] vcpu->cpu is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010052] the pcpu to handle the inject irq is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010055] the ipi sum is 50 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010093] vcpu->cpu is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010094] the pcpu to handle the inject irq is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010096] the ipi sum is 50 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.035829] vcpu->cpu is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.035831] the pcpu to handle the inject irq is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.035833] the ipi sum is 50 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106226] vcpu->cpu is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106229] the pcpu to handle the inject irq is 0 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106232] the ipi sum is 51 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106309] vcpu->cpu is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106311] the pcpu to handle the inject irq is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106313] the ipi sum is 51 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106359] vcpu->cpu is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106360] the pcpu to handle the inject irq is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106361] the ipi sum is 51 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106385] vcpu->cpu is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106386] the pcpu to handle the inject irq is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106387] the ipi sum is 51 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129867] vcpu->cpu is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129869] the pcpu to handle the inject irq is 0 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129871] the ipi sum is 52 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129937] vcpu->cpu is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129939] the pcpu to handle the inject irq is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129942] the ipi sum is 52 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129979] vcpu->cpu is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129981] the pcpu to handle the inject irq is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129983] the ipi sum is 52 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.130024] vcpu->cpu is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.130025] the pcpu to handle the inject irq is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.130026] the ipi sum is 52 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.137952] vcpu->cpu is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.137954] the pcpu to handle the inject irq is 0 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.137956] the ipi sum is 53 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138022] vcpu->cpu is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138024] the pcpu to handle the inject irq is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138026] the ipi sum is 53 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138064] vcpu->cpu is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138066] the pcpu to handle the inject irq is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138068] the ipi sum is 53 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138106] vcpu->cpu is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138107] the pcpu to handle the inject irq is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138108] the ipi sum is 53 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145844] vcpu->cpu is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145846] the pcpu to handle the inject irq is 0 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145848] the ipi sum is 54 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145911] vcpu->cpu is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145913] the pcpu to handle the inject irq is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145915] the ipi sum is 54 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145952] vcpu->cpu is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145954] the pcpu to handle the inject irq is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145956] the ipi sum is 54 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145993] vcpu->cpu is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145995] the pcpu to handle the inject irq is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.146002] the ipi sum is 54 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.187846] vcpu->cpu is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.187848] the pcpu to handle the inject irq is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.187850] the ipi sum is 54 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.187898] vcpu->cpu is 0 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.187900] the pcpu to handle the inject irq is 1 Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.187902] the ipi sum is 55 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.265951] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.265954] the pcpu to handle the inject irq is 0 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.265956] the ipi sum is 56 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266037] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266039] the pcpu to handle the inject irq is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266041] the ipi sum is 56 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266082] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266083] the pcpu to handle the inject irq is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266084] the ipi sum is 56 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266109] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266110] the pcpu to handle the inject irq is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266111] the ipi sum is 56 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274248] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274250] the pcpu to handle the inject irq is 0 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274252] the ipi sum is 57 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274318] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274320] the pcpu to handle the inject irq is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274322] the ipi sum is 57 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274370] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274372] the pcpu to handle the inject irq is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274374] the ipi sum is 57 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274413] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274414] the pcpu to handle the inject irq is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274415] the ipi sum is 57 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.281978] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.281981] the pcpu to handle the inject irq is 0 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.281983] the ipi sum is 58 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282046] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282048] the pcpu to handle the inject irq is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282050] the ipi sum is 58 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282100] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282102] the pcpu to handle the inject irq is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282104] the ipi sum is 58 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282144] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282145] the pcpu to handle the inject irq is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282146] the ipi sum is 58 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289860] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289862] the pcpu to handle the inject irq is 0 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289864] the ipi sum is 59 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289929] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289931] the pcpu to handle the inject irq is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289933] the ipi sum is 59 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289972] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289974] the pcpu to handle the inject irq is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289976] the ipi sum is 59 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.290018] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.290020] the pcpu to handle the inject irq is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.290021] the ipi sum is 59 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.305924] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.305926] the pcpu to handle the inject irq is 0 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.305928] the ipi sum is 60 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.305997] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.306000] the pcpu to handle the inject irq is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.306002] the ipi sum is 60 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.306040] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.306042] the pcpu to handle the inject irq is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.306044] the ipi sum is 60 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.306082] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.306083] the pcpu to handle the inject irq is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.306085] the ipi sum is 60 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.496784] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.496787] the pcpu to handle the inject irq is 0 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.496790] the ipi sum is 61 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.498717] vcpu->cpu is 0 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.498719] the pcpu to handle the inject irq is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.498720] the ipi sum is 62 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.499806] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.499808] the pcpu to handle the inject irq is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.499810] the ipi sum is 62 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.499844] vcpu->cpu is 0 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.499847] the pcpu to handle the inject irq is 0 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.499849] the ipi sum is 62 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.503811] vcpu->cpu is 0 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.503814] the pcpu to handle the inject irq is 0 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.503816] the ipi sum is 62 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.503848] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.503850] the pcpu to handle the inject irq is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.503852] the ipi sum is 62 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.507808] vcpu->cpu is 0 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.507811] the pcpu to handle the inject irq is 0 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.507813] the ipi sum is 62 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.511805] vcpu->cpu is 0 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.511807] the pcpu to handle the inject irq is 0 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.511809] the ipi sum is 62 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.515807] vcpu->cpu is 0 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.515809] the pcpu to handle the inject irq is 0 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.515811] the ipi sum is 62 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.596396] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.596399] the pcpu to handle the inject irq is 0 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.596402] the ipi sum is 63 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.687796] vcpu->cpu is 0 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.687799] the pcpu to handle the inject irq is 0 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.687801] the ipi sum is 63 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.687862] vcpu->cpu is 1 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.687864] the pcpu to handle the inject irq is 0 Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.687866] the ipi sum is 64 4: the above result just happen once, when i reboot the host, the IPI is not increase occured by kvm_vcpu_kick, i will check it more detail. YiLi Thanks 2012/12/4 Gleb Natapov <gleb@redhat.com>: > On Tue, Dec 04, 2012 at 11:08:41AM +0800, yi li wrote: >> The cpu inject the interrupt to vcpu which vcpu->cpu is the same as it. >> And it maybe avoid a IPI between the cpu core. >> > How often this happens in your testing? Regardless we cannot disable > preemption while iterating over all vcpus. Low latency people will kill > us. > >> Signed-off-by: Yi Li <yilikernel@gmail.com> >> >> --- linux/virt/kvm/irq_comm.c 2012-12-04 10:14:57.711024619 +0800 >> +++ linux/virt/kvm/irq_comm.c 2012-12-04 11:01:27.728859597 +0800 >> @@ -64,9 +64,10 @@ inline static bool kvm_is_dm_lowest_prio >> int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src, >> struct kvm_lapic_irq *irq) >> { >> - int i, r = -1; >> + int i, cpu, r = -1; >> struct kvm_vcpu *vcpu, *lowest = NULL; >> >> + cpu = get_cpu(); >> if (irq->dest_mode == 0 && irq->dest_id == 0xff && >> kvm_is_dm_lowest_prio(irq)) { >> printk(KERN_INFO "kvm: apic: phys broadcast and lowest prio\n"); >> @@ -89,13 +90,17 @@ int kvm_irq_delivery_to_apic(struct kvm >> r = 0; >> r += kvm_apic_set_irq(vcpu, irq); >> } else if (kvm_lapic_enabled(vcpu)) { >> - if (!lowest) >> + if(vcpu->cpu == cpu) { >> + lowest = vcpu; >> + break; >> + } >> + else if (!lowest) >> lowest = vcpu; >> else if (kvm_apic_compare_prio(vcpu, lowest) < 0) >> lowest = vcpu; >> } >> } >> - >> + put_cpu(); >> if (lowest) >> r = kvm_apic_set_irq(lowest, irq); >> >> >> YiLi >> Thanks >> -- >> To unsubscribe from this list: send the line "unsubscribe kvm" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- > Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
1: i have do ti again, result as blow: .......................................................................... [ 681.297899] the pcpu to handle the inject irq is 0 [ 681.297901] the ipi sum is 10432 root@liyi-ThinkPad-X200:~/myprobe# dmesg | grep 680. [ 680.065465] vcpu->cpu is 0 [ 680.065469] the pcpu to handle the inject irq is 0 [ 680.065472] the ipi sum is 10427 [ 680.065612] vcpu->cpu is 0 [ 680.065614] the pcpu to handle the inject irq is 0 [ 680.065616] the ipi sum is 10427 [ 680.065671] vcpu->cpu is 1 [ 680.065672] the pcpu to handle the inject irq is 0 [ 680.065674] the ipi sum is 10428 [ 680.297680] vcpu->cpu is 1 [ 680.297683] the pcpu to handle the inject irq is 1 [ 680.297685] the ipi sum is 10428 [ 680.297972] vcpu->cpu is 1 [ 680.297974] the pcpu to handle the inject irq is 0 [ 680.297975] the ipi sum is 10429 [ 680.549575] vcpu->cpu is 1 [ 680.549579] the pcpu to handle the inject irq is 1 [ 680.549581] the ipi sum is 10429 [ 680.565505] vcpu->cpu is 1 [ 680.565508] the pcpu to handle the inject irq is 1 [ 680.565510] the ipi sum is 10429 [ 680.565555] vcpu->cpu is 0 [ 680.565557] the pcpu to handle the inject irq is 1 [ 680.565559] the ipi sum is 10430 so we can see the IPI num is 3 between [680.065465] and [ 680.565559], the guest os has guest two vcpus, so if we have more, i think the ipi num will a little more. 2: i think your thinking is right about preempt disable problem,and i have no good idea for it. Thanks YiLi 2012/12/5 yi li <yilikernel@gmail.com>: > My test: > > 1:guest os has 2 vcpu and has a virtio netcard, also host os just has > 2 cpu cores, and do not do any smp_affinity > > 2:using the jprobe to probe the function kvm_vcpu_kick on the host > ....... > static int i=0; > int jkvm_vcpu_kick(struct kvm_vcpu *vcpu) > { > int cpu = vcpu->cpu; > printk("vcpu->cpu is %d\n",cpu); > printk("the pcpu to handle the inject irq is %d\n", smp_processor_id()); > if(cpu != smp_processor_id()) > { > i = i+ 1; > } > printk("the ipi sum is %d\n", i); > /* Always end with a call to jprobe_return(). */ > jprobe_return(); > return 0; > } > .......................... > > run the command ping the guestos virtio netcard > > 3: test result, > sometimes, it is very bad, you see blow, there has 14 ipi (64-50) > > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.009937] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.009940] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.009942] the ipi sum is 50 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010008] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010011] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010013] the ipi sum is 50 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010051] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010052] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010055] the ipi sum is 50 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010093] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010094] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010096] the ipi sum is 50 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.035829] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.035831] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.035833] the ipi sum is 50 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106226] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106229] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106232] the ipi sum is 51 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106309] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106311] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106313] the ipi sum is 51 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106359] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106360] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106361] the ipi sum is 51 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106385] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106386] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106387] the ipi sum is 51 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129867] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129869] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129871] the ipi sum is 52 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129937] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129939] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129942] the ipi sum is 52 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129979] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129981] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129983] the ipi sum is 52 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.130024] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.130025] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.130026] the ipi sum is 52 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.137952] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.137954] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.137956] the ipi sum is 53 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138022] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138024] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138026] the ipi sum is 53 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138064] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138066] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138068] the ipi sum is 53 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138106] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138107] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138108] the ipi sum is 53 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145844] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145846] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145848] the ipi sum is 54 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145911] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145913] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145915] the ipi sum is 54 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145952] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145954] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145956] the ipi sum is 54 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145993] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145995] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.146002] the ipi sum is 54 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.187846] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.187848] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.187850] the ipi sum is 54 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.187898] vcpu->cpu is 0 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.187900] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.187902] the ipi sum is 55 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.265951] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.265954] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.265956] the ipi sum is 56 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266037] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266039] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266041] the ipi sum is 56 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266082] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266083] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266084] the ipi sum is 56 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266109] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266110] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266111] the ipi sum is 56 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274248] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274250] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274252] the ipi sum is 57 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274318] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274320] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274322] the ipi sum is 57 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274370] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274372] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274374] the ipi sum is 57 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274413] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274414] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274415] the ipi sum is 57 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.281978] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.281981] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.281983] the ipi sum is 58 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282046] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282048] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282050] the ipi sum is 58 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282100] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282102] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282104] the ipi sum is 58 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282144] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282145] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282146] the ipi sum is 58 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289860] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289862] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289864] the ipi sum is 59 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289929] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289931] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289933] the ipi sum is 59 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289972] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289974] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289976] the ipi sum is 59 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.290018] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.290020] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.290021] the ipi sum is 59 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.305924] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.305926] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.305928] the ipi sum is 60 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.305997] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.306000] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.306002] the ipi sum is 60 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.306040] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.306042] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.306044] the ipi sum is 60 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.306082] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.306083] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.306085] the ipi sum is 60 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.496784] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.496787] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.496790] the ipi sum is 61 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.498717] vcpu->cpu is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.498719] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.498720] the ipi sum is 62 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.499806] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.499808] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.499810] the ipi sum is 62 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.499844] vcpu->cpu is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.499847] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.499849] the ipi sum is 62 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.503811] vcpu->cpu is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.503814] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.503816] the ipi sum is 62 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.503848] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.503850] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.503852] the ipi sum is 62 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.507808] vcpu->cpu is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.507811] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.507813] the ipi sum is 62 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.511805] vcpu->cpu is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.511807] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.511809] the ipi sum is 62 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.515807] vcpu->cpu is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.515809] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.515811] the ipi sum is 62 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.596396] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.596399] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.596402] the ipi sum is 63 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.687796] vcpu->cpu is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.687799] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.687801] the ipi sum is 63 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.687862] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.687864] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.687866] the ipi sum is 64 > > 4: the above result just happen once, when i reboot the host, the IPI > is not increase occured by kvm_vcpu_kick, i will check it more detail. > > YiLi > Thanks > > > 2012/12/4 Gleb Natapov <gleb@redhat.com>: >> On Tue, Dec 04, 2012 at 11:08:41AM +0800, yi li wrote: >>> The cpu inject the interrupt to vcpu which vcpu->cpu is the same as it. >>> And it maybe avoid a IPI between the cpu core. >>> >> How often this happens in your testing? Regardless we cannot disable >> preemption while iterating over all vcpus. Low latency people will kill >> us. >> >>> Signed-off-by: Yi Li <yilikernel@gmail.com> >>> >>> --- linux/virt/kvm/irq_comm.c 2012-12-04 10:14:57.711024619 +0800 >>> +++ linux/virt/kvm/irq_comm.c 2012-12-04 11:01:27.728859597 +0800 >>> @@ -64,9 +64,10 @@ inline static bool kvm_is_dm_lowest_prio >>> int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src, >>> struct kvm_lapic_irq *irq) >>> { >>> - int i, r = -1; >>> + int i, cpu, r = -1; >>> struct kvm_vcpu *vcpu, *lowest = NULL; >>> >>> + cpu = get_cpu(); >>> if (irq->dest_mode == 0 && irq->dest_id == 0xff && >>> kvm_is_dm_lowest_prio(irq)) { >>> printk(KERN_INFO "kvm: apic: phys broadcast and lowest prio\n"); >>> @@ -89,13 +90,17 @@ int kvm_irq_delivery_to_apic(struct kvm >>> r = 0; >>> r += kvm_apic_set_irq(vcpu, irq); >>> } else if (kvm_lapic_enabled(vcpu)) { >>> - if (!lowest) >>> + if(vcpu->cpu == cpu) { >>> + lowest = vcpu; >>> + break; >>> + } >>> + else if (!lowest) >>> lowest = vcpu; >>> else if (kvm_apic_compare_prio(vcpu, lowest) < 0) >>> lowest = vcpu; >>> } >>> } >>> - >>> + put_cpu(); >>> if (lowest) >>> r = kvm_apic_set_irq(lowest, irq); >>> >>> >>> YiLi >>> Thanks >>> -- >>> To unsubscribe from this list: send the line "unsubscribe kvm" in >>> the body of a message to majordomo@vger.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >> >> -- >> Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Dec 05, 2012 at 01:32:15AM +0800, yi li wrote: > My test: > > 1:guest os has 2 vcpu and has a virtio netcard, also host os just has > 2 cpu cores, and do not do any smp_affinity > What about running the same test but on 32 host cpus. I expect result to be much different. > 2:using the jprobe to probe the function kvm_vcpu_kick on the host > ....... > static int i=0; > int jkvm_vcpu_kick(struct kvm_vcpu *vcpu) > { > int cpu = vcpu->cpu; > printk("vcpu->cpu is %d\n",cpu); > printk("the pcpu to handle the inject irq is %d\n", smp_processor_id()); > if(cpu != smp_processor_id()) > { > i = i+ 1; > } > printk("the ipi sum is %d\n", i); > /* Always end with a call to jprobe_return(). */ > jprobe_return(); > return 0; > } > .......................... > > run the command ping the guestos virtio netcard > > 3: test result, > sometimes, it is very bad, you see blow, there has 14 ipi (64-50) > > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.009937] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.009940] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.009942] the ipi sum is 50 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010008] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010011] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010013] the ipi sum is 50 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010051] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010052] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010055] the ipi sum is 50 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010093] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010094] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.010096] the ipi sum is 50 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.035829] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.035831] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.035833] the ipi sum is 50 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106226] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106229] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106232] the ipi sum is 51 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106309] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106311] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106313] the ipi sum is 51 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106359] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106360] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106361] the ipi sum is 51 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106385] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106386] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.106387] the ipi sum is 51 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129867] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129869] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129871] the ipi sum is 52 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129937] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129939] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129942] the ipi sum is 52 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129979] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129981] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.129983] the ipi sum is 52 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.130024] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.130025] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.130026] the ipi sum is 52 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.137952] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.137954] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.137956] the ipi sum is 53 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138022] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138024] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138026] the ipi sum is 53 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138064] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138066] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138068] the ipi sum is 53 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138106] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138107] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.138108] the ipi sum is 53 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145844] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145846] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145848] the ipi sum is 54 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145911] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145913] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145915] the ipi sum is 54 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145952] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145954] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145956] the ipi sum is 54 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145993] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.145995] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.146002] the ipi sum is 54 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.187846] vcpu->cpu is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.187848] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.187850] the ipi sum is 54 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.187898] vcpu->cpu is 0 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.187900] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:52 liyi-ThinkPad-X200 kernel: [11470.187902] the ipi sum is 55 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.265951] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.265954] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.265956] the ipi sum is 56 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266037] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266039] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266041] the ipi sum is 56 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266082] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266083] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266084] the ipi sum is 56 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266109] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266110] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.266111] the ipi sum is 56 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274248] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274250] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274252] the ipi sum is 57 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274318] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274320] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274322] the ipi sum is 57 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274370] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274372] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274374] the ipi sum is 57 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274413] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274414] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.274415] the ipi sum is 57 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.281978] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.281981] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.281983] the ipi sum is 58 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282046] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282048] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282050] the ipi sum is 58 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282100] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282102] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282104] the ipi sum is 58 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282144] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282145] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.282146] the ipi sum is 58 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289860] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289862] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289864] the ipi sum is 59 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289929] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289931] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289933] the ipi sum is 59 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289972] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289974] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.289976] the ipi sum is 59 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.290018] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.290020] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.290021] the ipi sum is 59 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.305924] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.305926] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.305928] the ipi sum is 60 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.305997] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.306000] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.306002] the ipi sum is 60 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.306040] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.306042] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.306044] the ipi sum is 60 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.306082] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.306083] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.306085] the ipi sum is 60 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.496784] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.496787] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.496790] the ipi sum is 61 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.498717] vcpu->cpu is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.498719] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.498720] the ipi sum is 62 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.499806] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.499808] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.499810] the ipi sum is 62 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.499844] vcpu->cpu is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.499847] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.499849] the ipi sum is 62 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.503811] vcpu->cpu is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.503814] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.503816] the ipi sum is 62 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.503848] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.503850] the pcpu to > handle the inject irq is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.503852] the ipi sum is 62 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.507808] vcpu->cpu is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.507811] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.507813] the ipi sum is 62 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.511805] vcpu->cpu is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.511807] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.511809] the ipi sum is 62 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.515807] vcpu->cpu is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.515809] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.515811] the ipi sum is 62 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.596396] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.596399] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.596402] the ipi sum is 63 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.687796] vcpu->cpu is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.687799] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.687801] the ipi sum is 63 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.687862] vcpu->cpu is 1 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.687864] the pcpu to > handle the inject irq is 0 > Dec 5 00:04:53 liyi-ThinkPad-X200 kernel: [11470.687866] the ipi sum is 64 > > 4: the above result just happen once, when i reboot the host, the IPI > is not increase occured by kvm_vcpu_kick, i will check it more detail. > > YiLi > Thanks > > > 2012/12/4 Gleb Natapov <gleb@redhat.com>: > > On Tue, Dec 04, 2012 at 11:08:41AM +0800, yi li wrote: > >> The cpu inject the interrupt to vcpu which vcpu->cpu is the same as it. > >> And it maybe avoid a IPI between the cpu core. > >> > > How often this happens in your testing? Regardless we cannot disable > > preemption while iterating over all vcpus. Low latency people will kill > > us. > > > >> Signed-off-by: Yi Li <yilikernel@gmail.com> > >> > >> --- linux/virt/kvm/irq_comm.c 2012-12-04 10:14:57.711024619 +0800 > >> +++ linux/virt/kvm/irq_comm.c 2012-12-04 11:01:27.728859597 +0800 > >> @@ -64,9 +64,10 @@ inline static bool kvm_is_dm_lowest_prio > >> int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src, > >> struct kvm_lapic_irq *irq) > >> { > >> - int i, r = -1; > >> + int i, cpu, r = -1; > >> struct kvm_vcpu *vcpu, *lowest = NULL; > >> > >> + cpu = get_cpu(); > >> if (irq->dest_mode == 0 && irq->dest_id == 0xff && > >> kvm_is_dm_lowest_prio(irq)) { > >> printk(KERN_INFO "kvm: apic: phys broadcast and lowest prio\n"); > >> @@ -89,13 +90,17 @@ int kvm_irq_delivery_to_apic(struct kvm > >> r = 0; > >> r += kvm_apic_set_irq(vcpu, irq); > >> } else if (kvm_lapic_enabled(vcpu)) { > >> - if (!lowest) > >> + if(vcpu->cpu == cpu) { > >> + lowest = vcpu; > >> + break; > >> + } > >> + else if (!lowest) > >> lowest = vcpu; > >> else if (kvm_apic_compare_prio(vcpu, lowest) < 0) > >> lowest = vcpu; > >> } > >> } > >> - > >> + put_cpu(); > >> if (lowest) > >> r = kvm_apic_set_irq(lowest, irq); > >> > >> > >> YiLi > >> Thanks > >> -- > >> To unsubscribe from this list: send the line "unsubscribe kvm" in > >> the body of a message to majordomo@vger.kernel.org > >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > -- > > Gleb. -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
--- linux/virt/kvm/irq_comm.c 2012-12-04 10:14:57.711024619 +0800 +++ linux/virt/kvm/irq_comm.c 2012-12-04 11:01:27.728859597 +0800 @@ -64,9 +64,10 @@ inline static bool kvm_is_dm_lowest_prio int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src, struct kvm_lapic_irq *irq) { - int i, r = -1; + int i, cpu, r = -1; struct kvm_vcpu *vcpu, *lowest = NULL; + cpu = get_cpu(); if (irq->dest_mode == 0 && irq->dest_id == 0xff && kvm_is_dm_lowest_prio(irq)) { printk(KERN_INFO "kvm: apic: phys broadcast and lowest prio\n"); @@ -89,13 +90,17 @@ int kvm_irq_delivery_to_apic(struct kvm r = 0; r += kvm_apic_set_irq(vcpu, irq); } else if (kvm_lapic_enabled(vcpu)) { - if (!lowest) + if(vcpu->cpu == cpu) { + lowest = vcpu; + break; + } + else if (!lowest) lowest = vcpu; else if (kvm_apic_compare_prio(vcpu, lowest) < 0) lowest = vcpu; } } - + put_cpu(); if (lowest) r = kvm_apic_set_irq(lowest, irq);
The cpu inject the interrupt to vcpu which vcpu->cpu is the same as it. And it maybe avoid a IPI between the cpu core. Signed-off-by: Yi Li <yilikernel@gmail.com> YiLi Thanks -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html