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From: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
To: habanero@linux.vnet.ibm.com
Cc: Avi Kivity <avi@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	Ingo Molnar <mingo@redhat.com>, Rik van Riel <riel@redhat.com>,
	Srikar <srikar@linux.vnet.ibm.com>,
	"Nikunj A. Dadhania" <nikunj@linux.vnet.ibm.com>,
	KVM <kvm@vger.kernel.org>, Jiannan Ouyang <ouyang@cs.pitt.edu>,
	chegu vinod <chegu_vinod@hp.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Srivatsa Vaddagiri <srivatsa.vaddagiri@gmail.com>,
	Gleb Natapov <gleb@redhat.com>, Andrew Jones <drjones@redhat.com>
Subject: Re: [PATCH RFC 0/2] kvm: Improving undercommit,overcommit scenarios in PLE handler
Date: Fri, 28 Sep 2012 19:41:22 +0530	[thread overview]
Message-ID: <5065B00A.4050107@linux.vnet.ibm.com> (raw)
In-Reply-To: <1348832438.5551.5.camel@oc6622382223.ibm.com>

On 09/28/2012 05:10 PM, Andrew Theurer wrote:
> On Fri, 2012-09-28 at 11:08 +0530, Raghavendra K T wrote:
>> On 09/27/2012 05:33 PM, Avi Kivity wrote:
>>> On 09/27/2012 01:23 PM, Raghavendra K T wrote:
>>>>>
[...]
>>>
>>> Also there may be a lot of false positives (deferred preemptions even
>>> when there is no contention).
>
> It will be interesting to see how this behaves with a very high lock
> activity in a guest.  Once the scheduler defers preemption, is it for a
> fixed amount of time, or does it know to cut the deferral short as soon
> as the lock depth is reduced [by x]?

Design/protocol that Vatsa, had in mind was something like this:

- scheduler does not give a vcpu holding lock forever, it may give one
chance that would give only few ticks. In addition to giving chance,
scheduler also sets some indication that he has been given chance.

- vcpu once he release (all) the lock(s), if it had given chance,
it should clear that (ACK), and relinquish the cpu.





  reply	other threads:[~2012-09-28 14:15 UTC|newest]

Thread overview: 126+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-21 11:59 [PATCH RFC 0/2] kvm: Improving undercommit,overcommit scenarios in PLE handler Raghavendra K T
2012-09-21 12:00 ` [PATCH RFC 1/2] kvm: Handle undercommitted guest case " Raghavendra K T
2012-09-21 13:02   ` Rik van Riel
2012-09-21 17:24     ` Raghavendra K T
2012-09-24 15:41       ` Avi Kivity
2012-09-24 16:06         ` Avi Kivity
2012-09-24 16:14           ` Peter Zijlstra
2012-09-24 16:25             ` Avi Kivity
2012-09-25  8:09           ` Raghavendra K T
2012-09-25  8:54             ` Avi Kivity
2012-09-25 13:49               ` Raghavendra K T
2012-09-27  7:44               ` Gleb Natapov
2012-09-27  8:59                 ` Avi Kivity
2012-09-27  9:11                   ` Gleb Natapov
2012-09-27  9:33                     ` Avi Kivity
2012-09-27  9:58                       ` Gleb Natapov
2012-09-27 10:04                         ` Avi Kivity
2012-09-27 10:08                           ` Gleb Natapov
2012-09-27 10:15                             ` Avi Kivity
     [not found]               ` <CAJocwcf+8u84_yDC-PK0Yni93YSTWzYvr69nq6b3pNv1MwVJzQ@mail.gmail.com>
2012-09-27  8:50                 ` Avi Kivity
2012-09-27 11:26                   ` Raghavendra K T
2012-09-27 12:06                     ` Avi Kivity
2012-09-28 18:18                       ` Konrad Rzeszutek Wilk
2012-09-30  8:16                         ` Avi Kivity
     [not found]                   ` <CAJocwcc19F+PtsQ5okGMvYeVnkEigpZRpwWY9JgeRPFqfcVoXA@mail.gmail.com>
2012-09-28  6:16                     ` Raghavendra K T
2012-09-30  8:18                       ` Avi Kivity
2012-09-30 11:07                         ` Gleb Natapov
2012-09-30 11:13                           ` Avi Kivity
2012-10-03 14:17                             ` Raghavendra K T
2012-10-03 14:56                               ` Avi Kivity
2012-10-04  7:29                                 ` Gleb Natapov
2012-10-05  8:36                                   ` Raghavendra K T
2012-10-07  9:51                                     ` Avi Kivity
2012-09-25  7:36         ` Raghavendra K T
2012-09-25  8:12           ` Avi Kivity
2012-09-25 14:21             ` Takuya Yoshikawa
2012-09-27  8:43               ` Avi Kivity
2012-10-03 12:22         ` Raghavendra K T
2012-10-03 17:05           ` Avi Kivity
2012-10-04 10:49             ` Raghavendra K T
2012-10-04 12:41               ` Avi Kivity
2012-10-04 13:07                 ` Peter Zijlstra
2012-10-04 15:00                   ` Avi Kivity
2012-10-09 18:51                     ` Raghavendra K T
2012-10-10  2:59                       ` Andrew Theurer
2012-10-10 17:54                         ` Raghavendra K T
2012-10-10 18:03                           ` David Ahern
2012-10-10 18:14                             ` Raghavendra K T
2012-10-10 19:36                           ` Andrew Theurer
2012-10-15 12:10                             ` Raghavendra K T
2012-10-15 14:34                               ` Andrew Theurer
2012-10-19  8:30                                 ` Raghavendra K T
2012-10-19 13:31                                   ` Andrew Theurer
2012-10-10 14:24                       ` Andrew Theurer
2012-10-10 17:43                         ` Raghavendra K T
2012-10-10 19:27                           ` Andrew Theurer
2012-10-11 17:13                             ` Raghavendra K T
2012-10-11 10:39                         ` Nikunj A Dadhania
2012-10-18 12:39                       ` Avi Kivity
2012-10-19  8:19                         ` Raghavendra K T
2012-10-04 14:41                 ` Andrew Theurer
2012-10-05  9:06                   ` Raghavendra K T
2012-10-05  9:02                 ` Raghavendra K T
2012-09-24 11:33   ` Peter Zijlstra
2012-09-24 11:40     ` Raghavendra K T
2012-09-21 12:00 ` [PATCH RFC 2/2] kvm: Be courteous to other VMs in overcommitted scenario " Raghavendra K T
2012-09-21 13:22   ` Rik van Riel
2012-09-21 13:46   ` Takuya Yoshikawa
2012-09-21 13:52     ` Rik van Riel
2012-09-21 17:45       ` Raghavendra K T
2012-09-24 13:43         ` Takuya Yoshikawa
2012-09-24 15:26   ` Avi Kivity
2012-09-24 15:34     ` Peter Zijlstra
2012-09-24 15:43       ` Avi Kivity
2012-09-24 15:52         ` Peter Zijlstra
2012-09-24 15:58           ` Avi Kivity
2012-09-24 16:05             ` Peter Zijlstra
2012-09-24 16:10               ` Avi Kivity
2012-09-24 16:13                 ` Peter Zijlstra
2012-09-24 16:21                   ` Avi Kivity
2012-09-25 10:11                     ` Avi Kivity
2012-09-21 13:18 ` [PATCH RFC 0/2] kvm: Improving undercommit,overcommit scenarios " Chegu Vinod
2012-09-21 17:36   ` Raghavendra K T
2012-09-24  8:42     ` Dor Laor
2012-09-24 12:02       ` Raghavendra K T
2012-09-25 15:00         ` Dor Laor
2012-09-26 12:27           ` Konrad Rzeszutek Wilk
2012-09-27 10:07             ` Raghavendra K T
2012-09-27  9:49           ` Raghavendra K T
2012-09-27 10:28             ` Andrew Jones
2012-09-27 10:44               ` Avi Kivity
2012-09-27 11:31               ` Raghavendra K T
2012-09-27 10:33             ` Dor Laor
2012-09-24 11:34 ` Peter Zijlstra
2012-09-24 11:52   ` Raghavendra K T
2012-09-24 12:36     ` Peter Zijlstra
2012-09-24 13:29       ` Raghavendra K T
2012-09-24 13:54         ` Peter Zijlstra
2012-09-24 14:16           ` Raghavendra K T
2012-09-25 13:40             ` Raghavendra K T
2012-09-27  8:36               ` Avi Kivity
2012-09-27 11:23                 ` Raghavendra K T
2012-09-27 12:03                   ` Avi Kivity
2012-09-27 12:25                     ` Andrew Theurer
2012-09-28  5:38                     ` Raghavendra K T
2012-09-28  5:45                       ` H. Peter Anvin
2012-09-28  6:03                         ` Raghavendra K T
2012-09-28  8:38                       ` Peter Zijlstra
2012-09-28 11:40                       ` Andrew Theurer
2012-09-28 14:11                         ` Raghavendra K T [this message]
2012-09-28 14:13                         ` Peter Zijlstra
2012-09-30  8:24                         ` Avi Kivity
2012-10-03 14:29                     ` Raghavendra K T
2012-10-03 17:25                       ` Avi Kivity
2012-10-04 10:56                         ` Raghavendra K T
2012-10-04 12:44                           ` Avi Kivity
2012-10-05  9:04                             ` Raghavendra K T
2012-09-24 15:51           ` Avi Kivity
2012-09-24 16:03             ` Peter Zijlstra
2012-09-24 16:20               ` Avi Kivity
2012-09-26 13:20                 ` Andrew Jones
2012-09-26 13:26                   ` Peter Zijlstra
2012-09-26 13:39                     ` Andrew Jones
2012-09-26 13:45                       ` Peter Zijlstra
2012-09-26 12:57       ` Andrew Jones
2012-09-27 10:21         ` Raghavendra K T

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