From: Suravee Suthikulanit <suravee.suthikulpanit@amd.com>
To: Paul Durrant <Paul.Durrant@citrix.com>
Cc: George Dunlap <George.Dunlap@eu.citrix.com>,
Jan Beulich <JBeulich@suse.com>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Subject: Re: Time Skewing on Windows XP
Date: Tue, 12 Mar 2013 10:55:03 -0500 [thread overview]
Message-ID: <513F4FD7.8020305@amd.com> (raw)
In-Reply-To: <291EDFCB1E9E224A99088639C4762022013F7D2D2E18@LONPMAILBOX01.citrite.net>
On 3/12/2013 4:13 AM, Paul Durrant wrote:
>> -----Original Message-----
>> From: xen-devel-bounces@lists.xen.org [mailto:xen-devel-
>> bounces@lists.xen.org] On Behalf Of Suravee Suthikulpanit
>> Sent: 12 March 2013 04:40
>> To: George Dunlap; Jan Beulich
>> Cc: xen-devel@lists.xen.org
>> Subject: [Xen-devel] Time Skewing on Windows XP
>>
>> Hi,
>>
>> While I was investigating the following issue on Windows XP (both 32-bit and
>> 64-bit):
>>
>> * AMD NPT performance regression after c/s 24770:7f79475d3de7
>> Reference:http://marc.info/?l=xen-devel&m=135075376805215
>>
>>
>> On the latest source form xen-unstable, I ran into an issue where the timing
>> on the HVM guests skewing about 2x slower than the actual wall clock time.
>> This results in the system time slowing down. This is regardless of the
>> cpufreq governor scaling. (I tried with both ondemand and performance).
>>
>> However, I don't see the same behavior on the Win7 HVM guests. Is this a
>> known issue. I assume that XP and Win7 uses different mechanism for
>> keeping time (e.g. rdtsc vs. HPET)?
>>
> I think XP uses TSC and more recent versions of Windows use PM TIMER. Try booting XP with the /USEPMTIMER switch in boot.ini.
>
> Paul
Paul,
That still doesn't help in this case. I still see the WindowsXP guest
time skewing. Also, I would not think the normal RDTSC skewing should
be this severe (0.5x comparing to the wall-clock time).
Suravee
next prev parent reply other threads:[~2013-03-12 15:55 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-12 4:40 Time Skewing on Windows XP Suravee Suthikulpanit
2013-03-12 5:00 ` Steven Haigh
2013-03-12 8:03 ` Jan Beulich
2013-03-14 15:16 ` Suravee Suthikulanit
2013-03-14 16:06 ` Jan Beulich
2013-03-14 16:21 ` Suravee Suthikulanit
2013-03-14 16:34 ` Jan Beulich
2013-03-14 16:38 ` Suravee Suthikulanit
2013-03-14 17:03 ` Jan Beulich
2013-03-14 16:30 ` Tim Deegan
2013-03-14 16:43 ` Jan Beulich
2013-03-14 17:08 ` Tim Deegan
2013-03-14 20:23 ` Suravee Suthikulanit
2013-03-15 8:23 ` Jan Beulich
2013-03-21 12:33 ` Tim Deegan
2013-03-21 17:05 ` Jan Beulich
2013-03-14 16:24 ` Tim Deegan
2013-03-14 16:28 ` Jan Beulich
2013-03-12 9:13 ` Paul Durrant
2013-03-12 15:55 ` Suravee Suthikulanit [this message]
2013-03-12 16:13 ` Boris Ostrovsky
2013-03-12 18:25 ` Suravee Suthikulanit
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=513F4FD7.8020305@amd.com \
--to=suravee.suthikulpanit@amd.com \
--cc=George.Dunlap@eu.citrix.com \
--cc=JBeulich@suse.com \
--cc=Paul.Durrant@citrix.com \
--cc=xen-devel@lists.xen.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.