From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58564) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XbnIJ-0002GB-6S for qemu-devel@nongnu.org; Wed, 08 Oct 2014 05:12:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XbnID-0006s4-2c for qemu-devel@nongnu.org; Wed, 08 Oct 2014 05:12:27 -0400 Received: from mx1.redhat.com ([209.132.183.28]:13137) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XbnIC-0006rz-Ru for qemu-devel@nongnu.org; Wed, 08 Oct 2014 05:12:21 -0400 Date: Wed, 8 Oct 2014 12:15:47 +0300 From: "Michael S. Tsirkin" Message-ID: <20141008091547.GB3872@redhat.com> References: <542A6B70.7090607@huawei.com> <20140930093356.GA3673@redhat.com> <5434EB0B.8010800@cloudius-systems.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5434EB0B.8010800@cloudius-systems.com> Subject: Re: [Qemu-devel] [QA-virtio]:Why vring size is limited to 1024? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Avi Kivity Cc: Jason Wang , qemu-devel@nongnu.org, liuyongan@huawei.com, qinchuanyu@huawei.com, "Zhangjie (HZ)" , akong@redhat.com On Wed, Oct 08, 2014 at 10:43:07AM +0300, Avi Kivity wrote: > > On 09/30/2014 12:33 PM, Michael S. Tsirkin wrote: > >a single descriptor might use all of > >the virtqueue. In this case we wont to be able to pass the > >descriptor directly to linux as a single iov, since > > > > You could separate maximum request scatter/gather list size from the > virtqueue size. They are totally unrelated - even now you can have a larger > request by using indirect descriptors. We could add a feature to have a smaller or larger S/G length limit. Is this something useful? -- MST