From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: virtio scsi host draft specification, v3 Date: Wed, 29 Jun 2011 13:31:39 +0300 Message-ID: <20110629103139.GC16757@redhat.com> References: <4DEE2B15.4090809@redhat.com> <4DF21447.6090005@suse.de> <20110612075140.GB11941@redhat.com> <4E0AE0FE.2090905@redhat.com> <20110629100341.GC22900@infradead.org> <4E0AF925.2050707@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Christoph Hellwig , Hannes Reinecke , Linux Virtualization , Linux Kernel Mailing List , qemu-devel , Rusty Russell , Stefan Hajnoczi , Christoph Hellwig , "kvm@vger.kernel.org" To: Paolo Bonzini Return-path: Received: from mx1.redhat.com ([209.132.183.28]:53994 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751735Ab1F2Kbw (ORCPT ); Wed, 29 Jun 2011 06:31:52 -0400 Content-Disposition: inline In-Reply-To: <4E0AF925.2050707@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Wed, Jun 29, 2011 at 12:06:29PM +0200, Paolo Bonzini wrote: > On 06/29/2011 12:03 PM, Christoph Hellwig wrote: > >> I agree here, in fact I misread Hannes's comment as "if a driver > >> uses more than one queue it is responsibility of the driver to > >> ensure strict request ordering". If you send requests to different > >> queues, you know that those requests are independent. I don't think > >> anything else is feasible in the virtio framework. > > > >That doesn't really fit very well with the SAM model. If we want > >to use multiple queues for a single LUN it has to be transparent to > >the SCSI command stream. Then again I don't quite see the use for > >that anyway. > > Agreed, I see a use for multiple queues (MSI-X), but not for > multiple queues shared by a single LUN. > > Paolo Then let's make it explicit in the spec? -- MST