From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: Windows Server 2008R2 KVM guest performance issues Date: Tue, 27 Aug 2013 10:38:33 +0300 Message-ID: <20130827073833.GD22899@redhat.com> References: <521BA934.3050507@gameservers.com> <521C52A8.40801@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Brian Rak , kvm@vger.kernel.org To: Paolo Bonzini Return-path: Received: from mx1.redhat.com ([209.132.183.28]:9249 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752599Ab3H0HjJ (ORCPT ); Tue, 27 Aug 2013 03:39:09 -0400 Content-Disposition: inline In-Reply-To: <521C52A8.40801@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Tue, Aug 27, 2013 at 09:18:00AM +0200, Paolo Bonzini wrote: > > I've captured 20,000 lines of kvm trace output. This can be found > > https://gist.github.com/devicenull/fa8f49d4366060029ee4/raw/fb89720d34b43920be22e3e9a1d88962bf305da8/trace > > The guest is doing quite a lot of exits per second, mostly to (a) access > the ACPI timer I see a lot of PM timer access not ACPI timer. The solution for that is the patchset Brian linked. > (b) service NMIs. In fact, every NMI is reading the > timer too and causing an exit to QEMU. > Do you mean "kvm_exit: reason EXCEPTION_NMI rip 0xfffff800016dcf84 info 0 80000307"? Those are not NMIs, single NMI will kill Windows, they are #NM exceptions. Brian, is your workload uses floating point calculation? > So it is also possible that you have to debug this inside the guest, to > see if these exits are expected or not. > > Paolo > -- > 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 -- Gleb.