From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35939) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a9DFp-0004wg-25 for qemu-devel@nongnu.org; Wed, 16 Dec 2015 09:40:36 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1a9DFl-00078v-4k for qemu-devel@nongnu.org; Wed, 16 Dec 2015 09:40:32 -0500 Received: from e06smtp05.uk.ibm.com ([195.75.94.101]:55444) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a9DFk-00077m-KF for qemu-devel@nongnu.org; Wed, 16 Dec 2015 09:40:28 -0500 Received: from localhost by e06smtp05.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 16 Dec 2015 14:40:25 -0000 References: <1448388091-117282-1-git-send-email-pbonzini@redhat.com> <5656D2B9.3010802@de.ibm.com> <5656E158.3090505@redhat.com> <5668907A.80604@redhat.com> <56715EEE.6020208@de.ibm.com> From: Christian Borntraeger Message-ID: <567177C6.6010200@de.ibm.com> Date: Wed, 16 Dec 2015 15:40:06 +0100 MIME-Version: 1.0 In-Reply-To: <56715EEE.6020208@de.ibm.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit 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: Paolo Bonzini , 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 12/16/2015 01:54 PM, Christian Borntraeger wrote: > On 12/09/2015 09:35 PM, Paolo Bonzini wrote: >> >> >> 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. > > Just some quick remarks before I leave into vacation: > > Performance seems to be better than the initial version. In fact, it seems to be faster than 2.5-rc4. At least with the one single test case on null block devices that I run.