From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41918) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Xblu4-0001xI-8L for qemu-devel@nongnu.org; Wed, 08 Oct 2014 03:43:27 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Xbltw-0003es-Ek for qemu-devel@nongnu.org; Wed, 08 Oct 2014 03:43:20 -0400 Received: from mail-wg0-f48.google.com ([74.125.82.48]:37596) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Xbltw-0003em-A6 for qemu-devel@nongnu.org; Wed, 08 Oct 2014 03:43:12 -0400 Received: by mail-wg0-f48.google.com with SMTP id k14so9660916wgh.19 for ; Wed, 08 Oct 2014 00:43:11 -0700 (PDT) Message-ID: <5434EB0B.8010800@cloudius-systems.com> Date: Wed, 08 Oct 2014 10:43:07 +0300 From: Avi Kivity MIME-Version: 1.0 References: <542A6B70.7090607@huawei.com> <20140930093356.GA3673@redhat.com> In-Reply-To: <20140930093356.GA3673@redhat.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit 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: "Michael S. Tsirkin" , "Zhangjie (HZ)" Cc: liuyongan@huawei.com, qinchuanyu@huawei.com, Jason Wang , akong@redhat.com, qemu-devel@nongnu.org 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.