From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Yang, Sheng" Subject: Re: Performance test result between virtio_pci MSI-X disable and enable Date: Tue, 30 Nov 2010 17:24:16 +0800 Message-ID: <201011301724.16896.sheng.yang@intel.com> References: <4CEB6FCC.7000407@redhat.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Avi Kivity , Gleb Natapov , "mst@redhat.com" , "aliguori@us.ibm.com" , "rusty@rustcorp.com.au" , "kvm@vger.kernel.org" To: lidong chen Return-path: Received: from mga11.intel.com ([192.55.52.93]:60921 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752354Ab0K3JWv (ORCPT ); Tue, 30 Nov 2010 04:22:51 -0500 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On Tuesday 30 November 2010 17:10:11 lidong chen wrote: > sr-iov also meet this problem, MSIX mask waste a lot of cpu resource. > > I test kvm with sriov, which the vf driver could not disable msix. > so the host os waste a lot of cpu. cpu rate of host os is 90%. > > then I test xen with sriov, there ara also a lot of vm exits caused by > MSIX mask. > but the cpu rate of xen and domain0 is less than kvm. cpu rate of xen > and domain0 is 60%. > > without sr-iov, the cpu rate of xen and domain0 is higher than kvm. > > so i think the problem is kvm waste more cpu resource to deal with MSIX > mask. and we can see how xen deal with MSIX mask. > > if this problem sloved, maybe with MSIX enabled, the performace is better. Please refer to my posted patches for this issue. http://www.spinics.net/lists/kvm/msg44992.html -- regards Yang, Sheng > > 2010/11/23 Avi Kivity : > > On 11/23/2010 09:27 AM, lidong chen wrote: > >> can you tell me something about this problem. > >> thanks. > > > > Which problem? > > > > -- > > I have a truly marvellous patch that fixes the bug which this > > signature is too narrow to contain.