Re: [patch 2/2] KVM: x86: add option to advance tscdeadline hrtimer expiration

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 




On 11/12/2014 04:07, Marcelo Tosatti wrote:
>> > So, on APICv, if the interrupt is in PIR but it has bits 7:4 <=
>> > PPR[7:4], you have a problem. :(  There is no APICv hook that lets you
>> > get a vmexit when the PPR becomes low enough.
> Well, you simply exit earlier and busy spin for VM-exit
> time.

Okay, given how small the jitter is in your plots, a small busy wait is
not the end of the world even if it caused a very short priority
inversion.  Can you add a tracepoint that triggers when you do the busy
wait, and possibly a kvm stat that counts good (no busy wait) vs. bad
(busy wait) invocations of wait_lapic_expire?

Thanks,

Paolo
--
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




[Index of Archives]     [KVM ARM]     [KVM ia64]     [KVM ppc]     [Virtualization Tools]     [Spice Development]     [Libvirt]     [Libvirt Users]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite Questions]     [Linux Kernel]     [Linux SCSI]     [XFree86]
  Powered by Linux