From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [Qemu-devel] Anyone seeing huge slowdown launching qemu with Linux 2.6.35? Date: Wed, 04 Aug 2010 19:44:27 +0300 Message-ID: <4C5998EB.2050804@redhat.com> References: <4C5847CD.9080107@codemonkey.ws> <4C5848C7.3090806@redhat.com> <4C584982.5000108@codemonkey.ws> <4C584B66.5070404@redhat.com> <4C5854F1.3000905@codemonkey.ws> <4C5858B2.9090801@redhat.com> <4C585F5B.5070502@codemonkey.ws> <4C58635B.7020407@redhat.com> <20100803191346.GA28523@amd.home.annexia.org> <4C586C6E.9030002@redhat.com> <20100803200057.GB28523@amd.home.annexia.org> <4C5880BC.2080802@codemonkey.ws> <4C588685.8070509@redhat.com> <4C588B7D.5040902@codemonkey.ws> <4C591D87.5020809@redhat.com> <4C5962DA.4090108@codemonkey.ws> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Paolo Bonzini , "Richard W.M. Jones" , qemu-devel@nongnu.org, Gleb Natapov , kvm@vger.kernel.org To: Anthony Liguori Return-path: Received: from mx1.redhat.com ([209.132.183.28]:3874 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756382Ab0HDQod (ORCPT ); Wed, 4 Aug 2010 12:44:33 -0400 In-Reply-To: <4C5962DA.4090108@codemonkey.ws> Sender: kvm-owner@vger.kernel.org List-ID: On 08/04/2010 03:53 PM, Anthony Liguori wrote: > > So how do we enable support for more than 20 disks? I think a > virtio-scsi is inevitable.. Not only for large numbers of disks, also for JBOD performance. If you have one queue per disk you'll have low queue depths and high interrupt rates. Aggregating many spindles into a single queue is important for reducing overhead. -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain. From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=60111 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Ogh50-00018h-Vl for qemu-devel@nongnu.org; Wed, 04 Aug 2010 12:44:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1Ogh4z-0004nD-PR for qemu-devel@nongnu.org; Wed, 04 Aug 2010 12:44:34 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48377) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1Ogh4z-0004n1-Ir for qemu-devel@nongnu.org; Wed, 04 Aug 2010 12:44:33 -0400 Message-ID: <4C5998EB.2050804@redhat.com> Date: Wed, 04 Aug 2010 19:44:27 +0300 From: Avi Kivity MIME-Version: 1.0 Subject: Re: [Qemu-devel] Anyone seeing huge slowdown launching qemu with Linux 2.6.35? References: <4C5847CD.9080107@codemonkey.ws> <4C5848C7.3090806@redhat.com> <4C584982.5000108@codemonkey.ws> <4C584B66.5070404@redhat.com> <4C5854F1.3000905@codemonkey.ws> <4C5858B2.9090801@redhat.com> <4C585F5B.5070502@codemonkey.ws> <4C58635B.7020407@redhat.com> <20100803191346.GA28523@amd.home.annexia.org> <4C586C6E.9030002@redhat.com> <20100803200057.GB28523@amd.home.annexia.org> <4C5880BC.2080802@codemonkey.ws> <4C588685.8070509@redhat.com> <4C588B7D.5040902@codemonkey.ws> <4C591D87.5020809@redhat.com> <4C5962DA.4090108@codemonkey.ws> In-Reply-To: <4C5962DA.4090108@codemonkey.ws> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: Paolo Bonzini , kvm@vger.kernel.org, "Richard W.M. Jones" , Gleb Natapov , qemu-devel@nongnu.org On 08/04/2010 03:53 PM, Anthony Liguori wrote: > > So how do we enable support for more than 20 disks? I think a > virtio-scsi is inevitable.. Not only for large numbers of disks, also for JBOD performance. If you have one queue per disk you'll have low queue depths and high interrupt rates. Aggregating many spindles into a single queue is important for reducing overhead. -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.