Messages in this thread | | | Date | Thu, 26 May 2016 19:23:18 +0800 | Subject | Re: [PATCH v5] KVM: halt-polling: poll for the upcoming fire timers | From | Wanpeng Li <> |
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2016-05-26 18:30 GMT+08:00 Paolo Bonzini <pbonzini@redhat.com>: > > > On 26/05/2016 12:26, Paolo Bonzini wrote: >> As discussed on IRC, I would like to understand why the adaptive >> adjustment of halt_poll_ns is failing. It seems like you have so few >> halts that you don't get halt_poll_ns>0. Yet, when the VM halts, it's >> very close to the timer tick---often enough for this patch to have an >> effect. >> >> Please send a trace of halt_poll_ns_grow and halt_poll_ns_shrink >> tracepoints, so that we can find out more about this. > > And 30 seconds after I wrote this email, you told me on IRC that the > guest had HZ=1000 and the module parameter was set to 1 ms in order to > _really_ benefit from the patch. So basically you could obtain the same > effect with idle=poll in the guest. > > This explains why your reported results were not so great (as David noted).
Yeah, I will drop the patch.
Regards, Wanpeng Li
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