From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: large amount of NMI_INTERRUPT disgrade winxp VM performance much. Date: Thu, 11 Aug 2011 09:43:54 +0300 Message-ID: <4E437A2A.30606@redhat.com> References: <625BA99ED14B2D499DC4E29D8138F15062D2B8909F@shsmsx502.ccr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: ya su , "kvm@vger.kernel.org" To: "Tian, Kevin" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:46451 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752413Ab1HKGoB (ORCPT ); Thu, 11 Aug 2011 02:44:01 -0400 In-Reply-To: <625BA99ED14B2D499DC4E29D8138F15062D2B8909F@shsmsx502.ccr.corp.intel.com> Sender: kvm-owner@vger.kernel.org List-ID: On 08/11/2011 08:41 AM, Tian, Kevin wrote: > > qemu-system-x86-4454 [004] 549.958172: kvm_exit: > > reason EXCEPTION_NMI rip 0x8051d5e1 > > qemu-system-x86-4454 [004] 549.958172: kvm_page_fault: > > address c8f8a000 error_code b > > error_code 'b' means the page fault is caused by a write access in kernel > space, but related page entry has reserved bit set. This is usually used by > OS for some special tricks, e.g. to handle page swaps. You may check related > setting in win guest. > In this case it was kvm setting the reserved bit. Looking at your other trace, that server is probably an AMD with the NPT feature, while your first one is an Intel without the equivalent (EPT). For this type of workload, you need EPT or NPT. -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.