From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Haigh Subject: Re: Time Skewing on Windows XP Date: Tue, 12 Mar 2013 16:00:25 +1100 Message-ID: <513EB669.5030802@crc.id.au> References: <513EB1BC.9050803@amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <513EB1BC.9050803@amd.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On 03/12/2013 03:40 PM, Suravee Suthikulpanit wrote: > 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 found this recently as well... I didn't managed to come across a solution - however mine is on an Intel CPU. In the end, I just gave up and installed an NTP client on the WinXP systems. This updated the clock every hour so it doesn't drift enough to worry about anymore. If I disable this, it drifts a few hours each day. -- Steven Haigh Email: netwiz@crc.id.au Web: https://www.crc.id.au Phone: (03) 9001 6090 - 0412 935 897 Fax: (03) 8338 0299