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From: Avi Kivity <avi@redhat.com>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Dan Magenheimer <dan.magenheimer@oracle.com>,
	Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>,
	kurt.hackel@oracle.com, the arch/x86 maintainers <x86@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Glauber de Oliveira Costa <gcosta@redhat.com>,
	Xen-devel <xen-devel@lists.xensource.com>,
	Keir Fraser <keir.fraser@eu.citrix.com>,
	Zach Brown <zach.brown@oracle.com>,
	Chris Mason <chris.mason@oracle.com>
Subject: Re: [Xen-devel] Re: [PATCH 3/5] x86/pvclock: add	vsyscall	implementation
Date: Tue, 13 Oct 2009 08:39:32 +0200	[thread overview]
Message-ID: <4AD420A4.7050508@redhat.com> (raw)
In-Reply-To: <4AD37FE3.1010002@goop.org>

On 10/12/2009 09:13 PM, Jeremy Fitzhardinge wrote:
> On 10/12/09 11:29, Avi Kivity wrote:
>    
>> Good catch.  Doesn't that invalidate rdtscp based vgettimeofday on
>> non-virt as well (assuming p == cpu)?
>>      
> The tsc clocksource assumes the tsc is (mostly?) synced; it doesn't use
> rdtscp or make any attempt at per-cpu corrections.
>    

So it's broken or disabled when that assumption is wrong?  We could 
easily fix that now.  Might even reuse the pvclock structures.

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.


WARNING: multiple messages have this Message-ID (diff)
From: Avi Kivity <avi@redhat.com>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Dan Magenheimer <dan.magenheimer@oracle.com>,
	Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>,
	kurt.hackel@oracle.com, the arch/x86 maintainers <x86@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Glauber de Oliveira Costa <gcosta@redhat.com>,
	Xen-devel <xen-devel@lists.xensource.com>,
	Keir Fraser <keir.fraser@eu.citrix.com>,
	Zach Brown <zach.brown@oracle.com>,
	Chris Mason <chris.mason@oracle.com>
Subject: Re: Re: [PATCH 3/5] x86/pvclock: add	vsyscall	implementation
Date: Tue, 13 Oct 2009 08:39:32 +0200	[thread overview]
Message-ID: <4AD420A4.7050508@redhat.com> (raw)
In-Reply-To: <4AD37FE3.1010002@goop.org>

On 10/12/2009 09:13 PM, Jeremy Fitzhardinge wrote:
> On 10/12/09 11:29, Avi Kivity wrote:
>    
>> Good catch.  Doesn't that invalidate rdtscp based vgettimeofday on
>> non-virt as well (assuming p == cpu)?
>>      
> The tsc clocksource assumes the tsc is (mostly?) synced; it doesn't use
> rdtscp or make any attempt at per-cpu corrections.
>    

So it's broken or disabled when that assumption is wrong?  We could 
easily fix that now.  Might even reuse the pvclock structures.

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.

  reply	other threads:[~2009-10-13  6:41 UTC|newest]

Thread overview: 119+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-10-06  0:50 [PATCH RFC] Extending pvclock down to usermode for vsyscall Jeremy Fitzhardinge
2009-10-06  0:50 ` Jeremy Fitzhardinge
2009-10-06  0:50 ` [PATCH 1/5] x86/pvclock: make sure rdtsc doesn't speculate out of region Jeremy Fitzhardinge
2009-10-06  0:50   ` Jeremy Fitzhardinge
2009-10-06  0:50 ` [PATCH 2/5] x86/pvclock: no need to use strong read barriers in pvclock_get_time_values Jeremy Fitzhardinge
2009-10-06  0:50   ` Jeremy Fitzhardinge
2009-10-06  0:50 ` [PATCH 3/5] x86/pvclock: add vsyscall implementation Jeremy Fitzhardinge
2009-10-06  0:50   ` Jeremy Fitzhardinge
2009-10-06  9:04   ` Avi Kivity
2009-10-06  9:04     ` Avi Kivity
2009-10-06 14:19     ` Dan Magenheimer
2009-10-06 14:19       ` Dan Magenheimer
2009-10-06 15:11       ` Avi Kivity
2009-10-06 15:11         ` Avi Kivity
2009-10-06 18:46     ` [Xen-devel] " Jeremy Fitzhardinge
2009-10-06 18:46       ` Jeremy Fitzhardinge
2009-10-07 10:25       ` [Xen-devel] " Avi Kivity
2009-10-07 10:25         ` Avi Kivity
2009-10-07 19:29         ` [Xen-devel] " Jeremy Fitzhardinge
2009-10-07 19:29           ` Jeremy Fitzhardinge
2009-10-07 20:09           ` [Xen-devel] " Avi Kivity
2009-10-07 20:09             ` Avi Kivity
2009-10-07 21:19             ` [Xen-devel] " Jeremy Fitzhardinge
2009-10-07 21:19               ` Jeremy Fitzhardinge
2009-10-07 21:37               ` [Xen-devel] " Avi Kivity
2009-10-07 21:37                 ` Avi Kivity
2009-10-07 21:51                 ` [Xen-devel] " Jeremy Fitzhardinge
2009-10-07 21:51                   ` Jeremy Fitzhardinge
2009-10-07 21:53                   ` [Xen-devel] " Avi Kivity
2009-10-07 21:53                     ` Avi Kivity
2009-10-07 20:48         ` [Xen-devel] " Dan Magenheimer
2009-10-07 20:48           ` Dan Magenheimer
2009-10-07 21:08           ` [Xen-devel] " Avi Kivity
2009-10-07 21:08             ` Avi Kivity
2009-10-07 22:36             ` [Xen-devel] " Dan Magenheimer
2009-10-07 22:36               ` Dan Magenheimer
2009-10-10  0:24         ` [Xen-devel] " Jeremy Fitzhardinge
2009-10-10  0:24           ` Jeremy Fitzhardinge
2009-10-10 18:10           ` [Xen-devel] " Avi Kivity
2009-10-10 18:10             ` Avi Kivity
2009-10-12 18:20             ` [Xen-devel] " Jeremy Fitzhardinge
2009-10-12 18:20               ` Jeremy Fitzhardinge
2009-10-12 18:29               ` [Xen-devel] " Avi Kivity
2009-10-12 18:29                 ` Avi Kivity
2009-10-12 19:13                 ` [Xen-devel] " Jeremy Fitzhardinge
2009-10-12 19:13                   ` Jeremy Fitzhardinge
2009-10-13  6:39                   ` Avi Kivity [this message]
2009-10-13  6:39                     ` Avi Kivity
2009-10-13 20:00                     ` [Xen-devel] " Jeremy Fitzhardinge
2009-10-13 20:00                       ` Jeremy Fitzhardinge
2009-10-14 12:32                       ` [Xen-devel] " Avi Kivity
2009-10-14 12:32                         ` Avi Kivity
2009-10-15 19:17                         ` [Xen-devel] " Jeremy Fitzhardinge
2009-10-15 19:17                           ` Jeremy Fitzhardinge
2009-10-27 17:29                         ` [Xen-devel] " Dan Magenheimer
2009-10-27 17:29                           ` Dan Magenheimer
2009-10-27 18:20                           ` [Xen-devel] " Jeremy Fitzhardinge
2009-10-27 18:20                             ` Jeremy Fitzhardinge
2009-10-28  5:52                             ` [Xen-devel] " Avi Kivity
2009-10-28  5:52                               ` Avi Kivity
2009-10-28  9:29                               ` [Xen-devel] " Glauber Costa
2009-10-28  9:34                                 ` Avi Kivity
2009-10-28  9:34                                   ` Avi Kivity
2009-10-28 17:47                                   ` [Xen-devel] " Jeremy Fitzhardinge
2009-10-28 17:47                                     ` Jeremy Fitzhardinge
2009-10-29 12:13                                     ` [Xen-devel] " Avi Kivity
2009-10-29 12:13                                       ` Avi Kivity
2009-10-29 13:03                                       ` [Xen-devel] " Chris Mason
2009-10-29 13:03                                         ` Chris Mason
2009-10-29 14:46                                       ` [Xen-devel] " Dan Magenheimer
2009-10-29 14:46                                         ` Dan Magenheimer
2009-10-29 15:07                                         ` [Xen-devel] " Avi Kivity
2009-10-29 15:07                                           ` Avi Kivity
2009-10-29 15:55                                           ` [Xen-devel] " Dan Magenheimer
2009-10-29 15:55                                             ` Dan Magenheimer
2009-10-29 16:15                                             ` [Xen-devel] " Dan Magenheimer
2009-10-29 16:15                                               ` Dan Magenheimer
2009-11-01  9:28                                               ` [Xen-devel] " Avi Kivity
2009-11-01  9:28                                                 ` Avi Kivity
2009-11-02 15:28                                                 ` [Xen-devel] " Dan Magenheimer
2009-11-02 15:28                                                   ` Dan Magenheimer
2009-11-02 15:41                                                   ` [Xen-devel] " Avi Kivity
2009-11-02 15:41                                                     ` Avi Kivity
2009-11-01  9:32                                             ` [Xen-devel] " Avi Kivity
2009-11-01  9:32                                               ` Avi Kivity
2009-11-02 15:46                                               ` [Xen-devel] " Dan Magenheimer
2009-11-02 15:46                                                 ` Dan Magenheimer
2009-11-03  5:12                                                 ` [Xen-devel] " Avi Kivity
2009-11-03  5:12                                                   ` Avi Kivity
2009-11-04 20:30                                                   ` [Xen-devel] " Dan Magenheimer
2009-11-04 20:30                                                     ` Dan Magenheimer
2009-11-05  6:47                                                     ` [Xen-devel] " Avi Kivity
2009-11-05  6:47                                                       ` Avi Kivity
2009-11-05 14:52                                                       ` [Xen-devel] " Dan Magenheimer
2009-11-05 14:52                                                         ` Dan Magenheimer
2009-11-05 15:07                                                         ` [Xen-devel] " Keir Fraser
2009-11-05 15:07                                                           ` Keir Fraser
2009-11-04 21:19                                           ` [Xen-devel] " john stultz
2009-11-04 21:19                                             ` john stultz
2009-11-04 21:28                                             ` Dan Magenheimer
2009-11-04 21:28                                               ` Dan Magenheimer
2009-11-05  0:02                                               ` [Xen-devel] " john stultz
2009-11-05  0:02                                                 ` john stultz
2009-11-05  0:45                                                 ` [Xen-devel] " Dan Magenheimer
2009-11-05  0:45                                                   ` Dan Magenheimer
2009-10-30 23:30                                     ` pvclock implementation in pv_ops kernel: why not __native_read_tsc()? Dan Magenheimer
2009-10-31  1:17                                       ` Jeremy Fitzhardinge
2009-10-06  0:50 ` [PATCH 4/5] x86/fixmap: add a predicate for usermode fixmaps Jeremy Fitzhardinge
2009-10-06  0:50   ` Jeremy Fitzhardinge
2009-10-06 10:23   ` [Xen-devel] " Jan Beulich
2009-10-06 10:23     ` Jan Beulich
2009-10-06 18:47     ` [Xen-devel] " Jeremy Fitzhardinge
2009-10-06 18:47       ` Jeremy Fitzhardinge
2009-10-06  0:50 ` [PATCH 5/5] xen/time: add pvclock_clocksource_vread support Jeremy Fitzhardinge
2009-10-06  0:50   ` Jeremy Fitzhardinge
2009-10-06 10:28   ` [Xen-devel] " Jan Beulich
2009-10-06 10:28     ` Jan Beulich
2009-10-06 18:48     ` [Xen-devel] " Jeremy Fitzhardinge
2009-10-06 18:48       ` Jeremy Fitzhardinge

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