From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: PCI passthrough with VT-d - native performance Date: Wed, 16 Jul 2008 19:57:07 +0300 Message-ID: <487E2863.3000803@qumranet.com> References: <1216214225-18030-1-git-send-email-benami@il.ibm.com> <487E076D.4050306@qumranet.com> <1216221530.31546.274.camel@cluwyn.haifa.ibm.com> <487E125C.7020301@codemonkey.ws> <1216224796.31546.283.camel@cluwyn.haifa.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Anthony Liguori , amit.shah@qumranet.com, kvm@vger.kernel.org, Muli Ben-Yehuda , weidong.han@intel.com To: Ben-Ami Yassour Return-path: Received: from il.qumranet.com ([212.179.150.194]:55556 "EHLO il.qumranet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756376AbYGPQ5J (ORCPT ); Wed, 16 Jul 2008 12:57:09 -0400 In-Reply-To: <1216224796.31546.283.camel@cluwyn.haifa.ibm.com> Sender: kvm-owner@vger.kernel.org List-ID: Ben-Ami Yassour wrote: > >> That CPU utilization is extremely high and somewhat illogical if native >> w/vt-d has almost no CPU impact. Have you run oprofile yet or have any >> insight into where CPU is being burnt? >> >> What does kvm_stat look like? I wonder if there are a large number of >> PIO exits. What does the interrupt count look like on native vs. KVM >> with VT-d? >> >> Regards, >> >> Anthony Liguori >> >> > > These are all good points and questions, I agree that we need to take a deeper > look into the performance issues, but I think that we need to merge with > the main KVM tree first. > It would be good to get the host interrupt rate, to confirm that the host isn't flooded with interrupts. A deeper analysis can wait. -- error compiling committee.c: too many arguments to function