Re: [PATCH v5] KVM: halt-polling: poll for the upcoming fire timers

From: yunhong jiang
Date: Thu May 26 2016 - 16:42:04 EST


On Thu, 26 May 2016 12:26:27 +0200
Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:

>
>
> On 25/05/2016 04:47, Wanpeng Li wrote:
> > From: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
> >
> > If an emulated lapic timer will fire soon(in the scope of 10us the
> > base of dynamic halt-polling, lower-end of message passing workload
> > latency TCP_RR's poll time < 10us) we can treat it as a short halt,
> > and poll to wait it fire, the fire callback apic_timer_fn() will set
> > KVM_REQ_PENDING_TIMER, and this flag will be check during busy poll.
> > This can avoid context switch overhead and the latency which we wake
> > up vCPU.
>
> As discussed on IRC, I would like to understand why the adaptive

Glad to know the IRC channel. Is #kvm channel on freenode the IRC you are
talking about?

Thanks
--jyh