From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: Performance monitoring units and KVM II Date: Thu, 31 Jan 2008 04:44:55 +0100 Message-ID: <20080131034455.GC27115@one.firstfloor.org> References: <87wsprxmyb.fsf@pike.pond.sub.org> <47A0BE8F.4090508@qumranet.com> <200801310044.11055.balajirrao@gmail.com> <20080131031232.GB27115@one.firstfloor.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, Balaji Rao , markus.armbruster-5C7GfCeVMHo@public.gmane.org, avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org To: Andi Kleen Return-path: Content-Disposition: inline In-Reply-To: <20080131031232.GB27115-qrUzlfsMFqo/4alezvVtWx2eb7JE58TQ@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org > Sure it could, but that would be a new interface. If you were > free to define a new interface you could also just go completely > hypercall based. Actually thinking about it more it would be probably possible for KVM to emulate ArchPerfMon on AMD and Family 15 Intel based on the local PMU. ArchPerfmon has only a few defined counters which can likely be all emulated with other counters. Then the migration would work and PMU also. The only issue is that some clients might check the cpu vendor/model/family in addition to the ArchPerfMon. So to do successfull migration you would always need to fake an ArchPerfMon capable CPU in CPUID initially. So e.g. even if you ran on AMD SVM you would need to fake a Yonah or Core2.o Not sure if that had other bide side effects. Perhaps it could be made optional. -Andi ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/