public inbox for kvm@vger.kernel.org
 help / color / mirror / Atom feed
From: Antoine Martin <antoine@nagafix.co.uk>
To: dlaor@redhat.com
Cc: Kent Tong <kent@cpttm.org.mo>, kvm@vger.kernel.org
Subject: Re: recommended clock source
Date: Mon, 03 Aug 2009 15:11:44 +0700	[thread overview]
Message-ID: <4A769BC0.8010909@nagafix.co.uk> (raw)
In-Reply-To: <4A768B3B.6050402@redhat.com>

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

Hi,

Dor Laor wrote:
> On 08/03/2009 04:52 AM, Kent Tong wrote:
>> Hi,
>>
>> It seems to be an unsettled issue, but, would any kind soul suggest
>> the current
>> best practice for setting the clock in Ubuntu Linux and Windows guests?
> 
> For Linux the best source clock is the kvm pv clock (exist from 2.6.27
> and above).
# qemu-system-x86_64 -clock ?
Available alarm timers, in order of precedence:
dynticks
hpet
rtc
unix

I see no "pv clock"...
Which one should I use then?
Did I miss a ./configure or .config option?

Cheers
Antoine

> 
> For windows, standard acpi HAL uses the rtc clock by default. As long as
> you use the -rtc-td-hack it won't drift.
> 
> When the tsc is not stable on the host or the host cpu might get into
> deep sleep state (c2), you better use another source clock in the guest
> - for windows it should be the pmtimer (using the boot.ini).
> 
>>
>> Thanks!
>>
>> -- 
>> To unsubscribe from this list: send the line "unsubscribe kvm" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> -- 
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.9 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iEYEAREKAAYFAkp2m8AACgkQGK2zHPGK1rtQmACeM7UQJZS8TqVjqixZANKBm2gJ
kzMAnAxNjQj73tgRyxhP99dpQ0CpWXLW
=HWG8
-----END PGP SIGNATURE-----

  reply	other threads:[~2009-08-03  8:12 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-08-03  1:52 recommended clock source Kent Tong
2009-08-03  7:01 ` Dor Laor
2009-08-03  8:11   ` Antoine Martin [this message]
2009-08-03  8:29     ` Dor Laor
2009-08-03  9:09       ` Antoine Martin
2009-08-03  9:33         ` Dor Laor

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=4A769BC0.8010909@nagafix.co.uk \
    --to=antoine@nagafix.co.uk \
    --cc=dlaor@redhat.com \
    --cc=kent@cpttm.org.mo \
    --cc=kvm@vger.kernel.org \
    /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