public inbox for linux-kernel@vger.kernel.org
 help / color / mirror / Atom feed
From: Zachary Amsden <zamsden@redhat.com>
To: Jason Wang <jasowang@redhat.com>
Cc: avi@redhat.com, mtosatti@redhat.com, glommer@redhat.com,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 04/17] Fix deep C-state TSC desynchronization
Date: Wed, 16 Jun 2010 08:43:43 -1000	[thread overview]
Message-ID: <4C191B5F.7080109@redhat.com> (raw)
In-Reply-To: <4C18870C.9070707@redhat.com>

On 06/15/2010 10:10 PM, Jason Wang wrote:
> Zachary Amsden wrote:
>    
>> When CPUs with unstable TSCs enter deep C-state, TSC may stop
>> running.  This causes us to require resynchronization.  Since
>> we can't tell when this may potentially happen, we assume the
>> worst by forcing re-compensation for it at every point the VCPU
>> task is descheduled.
>>
>>
>>      
> Is there any method to do the compensation on host TSC when recovering
> from C-state? It should be simpler than do it on guest TSC.
>    

Actually, yes, we could re-calibrate from HPET.  Considering this patch 
is already broken, maybe that's a better idea.

  reply	other threads:[~2010-06-16 18:43 UTC|newest]

Thread overview: 70+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-06-15  7:34 TSC cleanups, fixes, documentation for KVM Zachary Amsden
2010-06-15  7:34 ` [PATCH 01/17] Eliminate duplicated timer code Zachary Amsden
2010-06-16 13:07   ` Glauber Costa
2010-06-15  7:34 ` [PATCH 02/17] Make cpu_tsc_khz updates use local CPU Zachary Amsden
2010-06-15  8:02   ` Avi Kivity
2010-06-15  7:34 ` [PATCH 03/17] Unify vendor TSC logic Zachary Amsden
2010-06-16  8:10   ` Jason Wang
2010-06-16 13:22     ` Glauber Costa
2010-06-17  8:03       ` Jason Wang
2010-06-16 18:42     ` Zachary Amsden
2010-06-17  8:15       ` Jason Wang
2010-06-17 20:30         ` Zachary Amsden
2010-06-15  7:34 ` [PATCH 04/17] Fix deep C-state TSC desynchronization Zachary Amsden
2010-06-15  8:09   ` Avi Kivity
2010-06-15  8:14     ` Zachary Amsden
2010-06-16  8:10   ` Jason Wang
2010-06-16 18:43     ` Zachary Amsden [this message]
2010-06-16 13:24   ` Glauber Costa
2010-06-16 19:20     ` Zachary Amsden
2010-06-15  7:34 ` [PATCH 05/17] Keep SMP VMs more in sync on unstable TSC Zachary Amsden
2010-06-15  8:11   ` Avi Kivity
2010-06-16  8:11   ` Jason Wang
2010-06-16 13:32   ` Glauber Costa
2010-06-16 21:15     ` Zachary Amsden
2010-06-15  7:34 ` [PATCH 06/17] Rename KVM_REQ_KVMCLOCK_UPDATE Zachary Amsden
2010-06-15  7:34 ` [PATCH 07/17] Perform hardware_enable in CPU_STARTING callback Zachary Amsden
2010-06-15  7:34 ` [PATCH 08/17] Add clock sync request to hardware enable Zachary Amsden
2010-06-15  8:24   ` Avi Kivity
2010-06-15  7:34 ` [PATCH 09/17] Move scale_delta into common header Zachary Amsden
2010-06-15  7:34 ` [PATCH 10/17] Make KVM clock computation work for other scales Zachary Amsden
2010-06-15  7:34 ` [PATCH 11/17] Fix a possible backwards warp of kvmclock Zachary Amsden
2010-06-15  8:40   ` Avi Kivity
2010-06-15 20:37     ` Zachary Amsden
2010-06-15 23:47   ` Marcelo Tosatti
2010-06-16  0:21     ` Zachary Amsden
2010-06-16  0:39       ` Marcelo Tosatti
2010-06-16  8:11   ` Jason Wang
2010-06-16 13:58     ` Glauber Costa
2010-06-16 14:13       ` Avi Kivity
2010-06-16 14:58         ` Glauber Costa
2010-06-16 22:38       ` Zachary Amsden
2010-06-16 19:36     ` Zachary Amsden
2010-06-15  7:34 ` [PATCH 12/17] Add helper function get_kernel_ns Zachary Amsden
2010-06-15  8:41   ` Avi Kivity
2010-06-15 21:03     ` Zachary Amsden
2010-06-15 21:13       ` john stultz
2010-06-16  8:12       ` Jason Wang
2010-06-16 14:03         ` Glauber Costa
2010-06-15  7:34 ` [PATCH 13/17] Add TSC offset tracking Zachary Amsden
2010-06-15  8:44   ` Avi Kivity
2010-06-15  7:34 ` [PATCH 14/17] Fix SVM VMCB reset Zachary Amsden
2010-06-15  7:34 ` [PATCH 15/17] Fix AMD C1 TSC desynchronization Zachary Amsden
2010-06-15  8:47   ` Avi Kivity
2010-06-15  9:21     ` Zachary Amsden
2010-06-15 14:46       ` Roedel, Joerg
2010-06-15  7:34 ` [PATCH 16/17] TSC reset compensation Zachary Amsden
2010-06-15  8:51   ` Avi Kivity
2010-06-15 20:32     ` Zachary Amsden
2010-06-16  0:27   ` Marcelo Tosatti
2010-06-16  0:32     ` Zachary Amsden
2010-06-16 13:52   ` Glauber Costa
2010-06-16 22:36     ` Zachary Amsden
2010-06-15  7:34 ` [PATCH 17/17] Add timekeeping documentation Zachary Amsden
2010-06-15  8:51   ` Avi Kivity
2010-06-15 20:27   ` Randy Dunlap
2010-06-16 23:59     ` Zachary Amsden
2010-06-17  8:55   ` Andi Kleen
2010-06-17 21:14     ` Zachary Amsden
2010-06-18  7:49       ` Andi Kleen
2010-06-18 16:33         ` Zachary Amsden

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=4C191B5F.7080109@redhat.com \
    --to=zamsden@redhat.com \
    --cc=avi@redhat.com \
    --cc=glommer@redhat.com \
    --cc=jasowang@redhat.com \
    --cc=kvm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mtosatti@redhat.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox