From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35537) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a07xO-0004td-SZ for qemu-devel@nongnu.org; Sat, 21 Nov 2015 08:11:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1a07xJ-0007td-QQ for qemu-devel@nongnu.org; Sat, 21 Nov 2015 08:11:58 -0500 Received: from mail-wm0-x22a.google.com ([2a00:1450:400c:c09::22a]:36494) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a07xJ-0007tZ-KS for qemu-devel@nongnu.org; Sat, 21 Nov 2015 08:11:53 -0500 Received: by wmww144 with SMTP id w144so48371320wmw.1 for ; Sat, 21 Nov 2015 05:11:52 -0800 (PST) Sender: Paolo Bonzini References: <1447978868-17138-1-git-send-email-mlin@kernel.org> From: Paolo Bonzini Message-ID: <56506D95.70101@redhat.com> Date: Sat, 21 Nov 2015 14:11:49 +0100 MIME-Version: 1.0 In-Reply-To: <1447978868-17138-1-git-send-email-mlin@kernel.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [RFC PATCH 0/9] vhost-nvme: new qemu nvme backend using nvme target List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Ming Lin , linux-nvme@lists.infradead.org Cc: virtualization@lists.linux-foundation.org, Christoph Hellwig , qemu-devel@nongnu.org On 20/11/2015 01:20, Ming Lin wrote: > One improvment could be to use google's NVMe vendor extension that > I send in another thread, aslo here: > https://git.kernel.org/cgit/linux/kernel/git/mlin/linux.git/log/?h=nvme-google-ext > > Qemu side: > http://www.minggr.net/cgit/cgit.cgi/qemu/log/?h=vhost-nvme.0 > Kernel side also here: > https://git.kernel.org/cgit/linux/kernel/git/mlin/linux.git/log/?h=vhost-nvme.0 How much do you get with vhost-nvme plus vendor extension, compared to 190 MB/s for QEMU? Note that in all likelihood, QEMU can actually do better than 190 MB/s, and gain more parallelism too, by moving the processing of the ioeventfds to a separate thread. This is similar to hw/block/dataplane/virtio-blk.c. It's actually pretty easy to do. Even though hw/block/dataplane/virtio-blk.c is still using some old APIs, all memory access in QEMU is now thread-safe. I have pending patches for 2.6 that cut that file down to a mere 200 lines of code, NVMe would probably be about the same. Paolo