From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1N7UT3-0007g6-Ro for qemu-devel@nongnu.org; Mon, 09 Nov 2009 08:39:37 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1N7USz-0007fP-29 for qemu-devel@nongnu.org; Mon, 09 Nov 2009 08:39:37 -0500 Received: from [199.232.76.173] (port=53293 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1N7USy-0007fL-RU for qemu-devel@nongnu.org; Mon, 09 Nov 2009 08:39:32 -0500 Received: from mx1.redhat.com ([209.132.183.28]:56361) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1N7USy-0003zI-D7 for qemu-devel@nongnu.org; Mon, 09 Nov 2009 08:39:32 -0500 Message-ID: <4AF81B8C.5040105@redhat.com> Date: Mon, 09 Nov 2009 14:39:24 +0100 From: Gerd Hoffmann MIME-Version: 1.0 Subject: Re: [Qemu-devel] [sneak preview] major scsi overhaul References: <4AF4ACA5.2090701@redhat.com> <4AF7DC02.2070308@redhat.com> <4AF80CFF.1090607@redhat.com> <4AF81329.5030904@redhat.com> <4AF81670.6040500@redhat.com> In-Reply-To: <4AF81670.6040500@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Avi Kivity Cc: Blue Swirl , "qemu-devel@nongnu.org" Hi, >> Doesn't fly. Either every SCSI HBA uses QEMUSG64List (thus making this >> aequivalent to the next option from the scsi point of view), or >> scsi-disk would have to support both formats. > > A device or device set which is always 64-bit would always use > QEMUSG64List. A device which is always 32-bit would use QEMUSG32List. A scsi-disk can be connected to both 32-bit and 64-bit HBAs though ... >> Question is how big the performance hit actually is and whenever we >> are willing to accept that or not ... > > Probably unmeasurable, but the qemu-devel thread size will be very > measurable so not worth it. ;) cheers, Gerd