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Date: Fri, 27 May 2016 17:14:57 -0700
From: yunhong jiang <yunhong.jiang@linux.intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Wanpeng Li <kernellwp@gmail.com>, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org, Wanpeng Li <wanpeng.li@hotmail.com>,
        Radim =?UTF-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>,
        David Matlack <dmatlack@google.com>,
        Christian Borntraeger <borntraeger@de.ibm.com>,
        Yang Zhang <yang.zhang.wz@gmail.com>
Subject: Re: [PATCH v5] KVM: halt-polling: poll for the upcoming fire timers
Message-ID: <20160527171457.63d895f0@jnakajim-build>
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On Fri, 27 May 2016 11:49:26 +0200
Paolo Bonzini <pbonzini@redhat.com> wrote:

> 
> 
> On 26/05/2016 22:33, yunhong jiang wrote:
> > On Thu, 26 May 2016 12:26:27 +0200
> > Paolo Bonzini <pbonzini@redhat.com> wrote:
> > 
> >>
> >>
> >> On 25/05/2016 04:47, Wanpeng Li wrote:
> >>> From: Wanpeng Li <wanpeng.li@hotmail.com>
> >>>
> >>> 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?
> 
> No, it's #qemu on irc.oftc.net

Thanks for the information.

--jyh

> 
> Thanks,
> 
> Paolo