From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Theurer Subject: Re: KVM performance vs. Xen Date: Thu, 30 Apr 2009 09:04:22 -0500 Message-ID: <49F9AFE6.8010704@linux.vnet.ibm.com> References: <49F8672E.5080507@linux.vnet.ibm.com> <49F967AE.4040905@redhat.com> <49F9AB64.20506@codemonkey.ws> <49F9AEC0.2060909@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Anthony Liguori , kvm-devel To: Avi Kivity Return-path: Received: from e1.ny.us.ibm.com ([32.97.182.141]:45714 "EHLO e1.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755535AbZD3OE1 (ORCPT ); Thu, 30 Apr 2009 10:04:27 -0400 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e1.ny.us.ibm.com (8.13.1/8.13.1) with ESMTP id n3UE0tTV000962 for ; Thu, 30 Apr 2009 10:00:55 -0400 Received: from d01av01.pok.ibm.com (d01av01.pok.ibm.com [9.56.224.215]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v9.2) with ESMTP id n3UE4QjF160216 for ; Thu, 30 Apr 2009 10:04:26 -0400 Received: from d01av01.pok.ibm.com (loopback [127.0.0.1]) by d01av01.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id n3UE4QoC026914 for ; Thu, 30 Apr 2009 10:04:26 -0400 In-Reply-To: <49F9AEC0.2060909@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Avi Kivity wrote: > Anthony Liguori wrote: >> Avi Kivity wrote: >>>> >>>> 1) I'm seeing about 2.3% in scheduler functions [that I recognize]. >>>> Does that seems a bit excessive? >>> >>> Yes, it is. If there is a lot of I/O, this might be due to the >>> thread pool used for I/O. >> >> This is why I wrote the linux-aio patch. It only reduced CPU >> consumption by about 2% although I'm not sure if that's absolute or >> relative. Andrew? If I recall correctly, it was 2.4% and relative. But with 2.3% in scheduler functions, that's what I expected. > > Was that before or after the entire path was made copyless? If this is referring to the preadv/writev support, no, I have not tested with that. -Andrew