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From: Rik van Riel <riel@redhat.com>
To: Avi Kivity <avi@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Ingo Molnar <mingo@elte.hu>,
	Anthony Liguori <aliguori@linux.vnet.ibm.com>
Subject: Re: [RFC PATCH 3/3] kvm: use yield_to instead of sleep in kvm_vcpu_on_spin
Date: Thu, 09 Dec 2010 12:07:32 -0500	[thread overview]
Message-ID: <4D010CD4.4020400@redhat.com> (raw)
In-Reply-To: <4D00AF3C.40603@redhat.com>

On 12/09/2010 05:28 AM, Avi Kivity wrote:
> On 12/09/2010 12:38 AM, Rik van Riel wrote:
>>
>>>> - /* Sleep for 100 us, and hope lock-holder got scheduled */
>>>> - expires = ktime_add_ns(ktime_get(), 100000UL);
>>>> - schedule_hrtimeout(&expires, HRTIMER_MODE_ABS);
>>>> + if (first_round&& last_boosted_vcpu == kvm->last_boosted_vcpu) {
>>>> + /* We have not found anyone yet. */
>>>> + first_round = 0;
>>>> + goto again;
>>>
>>> Need to guarantee termination.
>>
>> We do that by setting first_round to 0 :)
>>
>> We at most walk N+1 VCPUs in a VM with N VCPUs, with
>> this patch.
>>
>
> Right. May be clearer by using a for () loop instead of the goto.

And open coding kvm_for_each_vcpu ?

Somehow I suspect that won't add to clarity...

-- 
All rights reversed

  reply	other threads:[~2010-12-09 17:07 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-12-02 19:41 [RFC PATCH 0/3] directed yield for Pause Loop Exiting Rik van Riel
2010-12-02 19:43 ` [RFC PATCH 1/3] kvm: keep track of which task is running a KVM vcpu Rik van Riel
2010-12-03  1:18   ` Chris Wright
2010-12-03 14:50     ` Rik van Riel
2010-12-03 15:55       ` Chris Wright
2010-12-05 12:40       ` Avi Kivity
2010-12-03 12:17   ` Srivatsa Vaddagiri
2010-12-03 14:16     ` Rik van Riel
2010-12-05 12:59       ` Avi Kivity
2010-12-02 19:44 ` [RFC PATCH 2/3] sched: add yield_to function Rik van Riel
2010-12-03  0:50   ` Chris Wright
2010-12-03 18:27     ` Rik van Riel
2010-12-03 19:30       ` Chris Wright
2010-12-03 21:30       ` Peter Zijlstra
2010-12-03  5:54   ` Mike Galbraith
2010-12-03 13:46     ` Srivatsa Vaddagiri
2010-12-03 14:45       ` Mike Galbraith
2010-12-03 14:48         ` Rik van Riel
2010-12-03 15:09           ` Mike Galbraith
2010-12-03 15:35             ` Rik van Riel
2010-12-03 16:20               ` Srivatsa Vaddagiri
2010-12-03 17:09                 ` Rik van Riel
2010-12-03 17:29                   ` Srivatsa Vaddagiri
2010-12-03 17:33                     ` Rik van Riel
2010-12-03 17:45                       ` Srivatsa Vaddagiri
2010-12-03 20:05               ` Mike Galbraith
2010-12-03 21:26             ` Peter Zijlstra
2010-12-03 13:23   ` Peter Zijlstra
2010-12-03 13:30     ` Srivatsa Vaddagiri
2010-12-03 14:03       ` Peter Zijlstra
2010-12-03 14:06         ` Srivatsa Vaddagiri
2010-12-03 14:10           ` Srivatsa Vaddagiri
2010-12-03 21:23             ` Peter Zijlstra
2010-12-04 13:02               ` Rik van Riel
2010-12-10  4:34           ` Rik van Riel
2010-12-10  8:39             ` Srivatsa Vaddagiri
2010-12-10 14:55               ` Rik van Riel
2010-12-08 17:55     ` Rik van Riel
2010-12-08 20:00       ` Peter Zijlstra
2010-12-08 20:04         ` Peter Zijlstra
2010-12-08 22:59         ` Rik van Riel
2010-12-02 19:45 ` [RFC PATCH 3/3] kvm: use yield_to instead of sleep in kvm_vcpu_on_spin Rik van Riel
2010-12-03  2:24   ` Chris Wright
2010-12-05 12:58     ` Avi Kivity
2010-12-05 12:56   ` Avi Kivity
2010-12-08 22:38     ` Rik van Riel
2010-12-09 10:28       ` Avi Kivity
2010-12-09 17:07         ` Rik van Riel [this message]
2010-12-11  7:27           ` Avi Kivity
2010-12-02 22:41 ` [RFC PATCH 0/3] directed yield for Pause Loop Exiting Chris Wright
2010-12-05 13:02   ` Avi Kivity
2010-12-10  5:03 ` Balbir Singh
2010-12-10 14:54   ` Rik van Riel
2010-12-11  7:31   ` Avi Kivity
2010-12-11 13:57     ` Balbir Singh
2010-12-13 11:57       ` Avi Kivity
2010-12-13 12:39         ` Balbir Singh
2010-12-13 12:42           ` Avi Kivity
2010-12-13 17:02       ` Rik van Riel
2010-12-14  9:25         ` Balbir Singh

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