 Home |
Products |
Support |
Community |
News |
xen-devel
Re: [Xen-devel] [PATCH] Disable Xen PowerNow! support on Opteron 2nd gen
| To: | Ian Pratt <Ian.Pratt@xxxxxxxxxxxxx>, Mark Langsdorf <mark.langsdorf@xxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx> |
|---|---|
| Subject: | Re: [Xen-devel] [PATCH] Disable Xen PowerNow! support on Opteron 2nd gen and earlier processors |
| From: | Keir Fraser <Keir.Fraser@xxxxxxxxxxxx> |
| Date: | Tue, 22 Jan 2008 21:51:51 +0000 |
| Delivery-date: | Tue, 22 Jan 2008 13:52:09 -0800 |
| Envelope-to: | www-data@xxxxxxxxxxxxxxxxxx |
| In-reply-to: | <DD74FBB8EE28D441903D56487861CD9D273ABB3D@xxxxxxxxxxxxxxxxxxxxxx> |
| List-help: | <mailto:xen-devel-request@lists.xensource.com?subject=help> |
| List-id: | Xen developer discussion <xen-devel.lists.xensource.com> |
| List-post: | <mailto:xen-devel@lists.xensource.com> |
| List-subscribe: | <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe> |
| List-unsubscribe: | <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe> |
| Sender: | xen-devel-bounces@xxxxxxxxxxxxxxxxxxx |
| Thread-index: | AchdJLibYAsM6tf0TQmN0NytQtkgrAAFoN6AAAFwnhM= |
| Thread-topic: | [Xen-devel] [PATCH] Disable Xen PowerNow! support on Opteron 2nd gen and earlier processors |
| User-agent: | Microsoft-Entourage/11.3.6.070618 |
On 22/1/08 21:16, "Ian Pratt" <Ian.Pratt@xxxxxxxxxxxxx> wrote: >> The Xen hypervisor uses the TSC as a time source. 1st and 2nd >> generation AMD >> Operton processors have TSCs that change with frequency under power >> management. >> The Xen hypervisor currently cannot cope with the way the TSCs change >> and the time will regularly go backwards on multicore systems. > > Surely it should be possible to inform Xen of frequency changes (other > that T-states due to thermal throttling) and hence allow Xen to ensure > monotonicity? Xen itself does not require that the CPUs run with the > same rate TSC. It does need to know what frequency they're running at, > and when they change. Yes, and that is already done, hooked off the cpu notifier callback chain. Nobbling the C- and P-state logic shouldn't be necessary. -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel |
| Previous by Date: | Re: [Xen-devel] [PATCH] respin of mprotect performance patch, Bruce Rogers |
|---|---|
| Next by Date: | [Xen-devel] sizeof(long) different under windows x64 and linux x64, James Harper |
| Previous by Thread: | RE: [Xen-devel] [PATCH] Disable Xen PowerNow! support on Opteron 2nd gen and earlier processors, Ian Pratt |
| Next by Thread: | RE: [Xen-devel] [PATCH] Disable Xen PowerNow! support on Opteron2nd gen and earlier processors, Tian, Kevin |
| Indexes: | [Date] [Thread] [Top] [All Lists] |
