2016-05-26 18:30 GMT+08:00 Paolo Bonzini <pbonzini@xxxxxxxxxx>: > > > 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 -- 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
