From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50628) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a6lSF-0000PT-S1 for qemu-devel@nongnu.org; Wed, 09 Dec 2015 15:35:16 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1a6lSF-0004Ip-18 for qemu-devel@nongnu.org; Wed, 09 Dec 2015 15:35:15 -0500 Sender: Paolo Bonzini References: <1448388091-117282-1-git-send-email-pbonzini@redhat.com> <5656D2B9.3010802@de.ibm.com> <5656E158.3090505@redhat.com> From: Paolo Bonzini Message-ID: <5668907A.80604@redhat.com> Date: Wed, 9 Dec 2015 21:35:06 +0100 MIME-Version: 1.0 In-Reply-To: <5656E158.3090505@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [RFC PATCH 00/40] Sneak peek of virtio and dataplane changes for 2.6 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Christian Borntraeger , qemu-devel@nongnu.org, qemu-block@nongnu.org Cc: mlin@kernel.org, famz@redhat.com, ming.lei@canonical.com, stefanha@redhat.com, mst@redhat.com On 26/11/2015 11:39, Paolo Bonzini wrote: > I would really prefer to get rid of vring.c as soon as the infrastructure > makes it possible---even if it's faster. We know what makes virtio.c > slower, and it's simpler to fix virtio.c than to convert all the other > models to vring.c _plus_ make vring.c safe for migration. I've now pushed some optimizations of exec.c to the same place (branch dataplane, git://github.com/bonzini/qemu.git). Basically if the length of an address_space_read is constant, and the target ends up being RAM, the compiler can inline address_space_read in the caller and in particular eliminate the memcpy. Paolo