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From: Avi Kivity <avi@redhat.com>
To: Konrad Rzeszutek Wilk <konrad@kernel.org>
Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>,
	Jiannan Ouyang <ouyang@cs.pitt.edu>,
	Peter Zijlstra <peterz@infradead.org>,
	Rik van Riel <riel@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	Ingo Molnar <mingo@redhat.com>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	Srikar <srikar@linux.vnet.ibm.com>,
	"Nikunj A. Dadhania" <nikunj@linux.vnet.ibm.com>,
	KVM <kvm@vger.kernel.org>, chegu vinod <chegu_vinod@hp.com>,
	"Andrew M. Theurer" <habanero@linux.vnet.ibm.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Srivatsa Vaddagiri <srivatsa.vaddagiri@gmail.com>,
	Gleb Natapov <gleb@redhat.com>
Subject: Re: [PATCH RFC 1/2] kvm: Handle undercommitted guest case in PLE handler
Date: Sun, 30 Sep 2012 10:16:31 +0200	[thread overview]
Message-ID: <5067FFDF.2050501@redhat.com> (raw)
In-Reply-To: <20120928181801.GB17449@localhost.localdomain>

On 09/28/2012 08:18 PM, Konrad Rzeszutek Wilk wrote:
>> >> PLE:
>> >> - works for unmodified / non-Linux guests
>> >> - works for all types of spins (e.g. smp_call_function*())
>> >> - utilizes an existing hardware interface (PAUSE instruction) so likely
>> >> more robust compared to a software interface
>> >>
>> >> PV:
>> >> - has more information, so it can perform better
>> > 
>> > Should we also consider that we always have an edge here for non-PLE
>> > machine?
>> 
>> True.  The deployment share for these is decreasing rapidly though.  I
>> hate optimizing for obsolete hardware.
> 
> Keep in mind that the patchset that Jeremy provided also cleans (remove)
> parts of the pv spinlock code. It removes the various spin_lock,
> spin_unlock, etc that touch paravirt code. Instead the pv code is only
> in the slowpath. And if you don't compile with CONFIG_PARAVIRT_SPINLOCK
> the end code is the same as it is now.

We still need to maintain information about the lock holder if pv is
enabled at all, even if it is never used.

> On a different subject-  I am curious whether the Haswell new locking
> instructions (the transactional ones?) can be put in usage for the slow
> case?

Transactions are blown on any context switch, so no.

-- 
error compiling committee.c: too many arguments to function

  reply	other threads:[~2012-09-30  8:17 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 [this message]
     [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
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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