From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932674AbaFTPaG (ORCPT ); Fri, 20 Jun 2014 11:30:06 -0400 Received: from mail-pb0-f43.google.com ([209.85.160.43]:40618 "EHLO mail-pb0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932389AbaFTPaD (ORCPT ); Fri, 20 Jun 2014 11:30:03 -0400 From: Ming Lei To: Jens Axboe , linux-kernel@vger.kernel.org Cc: Rusty Russell , linux-api@vger.kernel.org, virtualization@lists.linux-foundation.org, "Michael S. Tsirkin" , Stefan Hajnoczi , Paolo Bonzini Subject: [PATCH v1 0/2] block: virtio-blk: support multi vq per virtio-blk Date: Fri, 20 Jun 2014 23:29:38 +0800 Message-Id: <1403278181-28455-1-git-send-email-ming.lei@canonical.com> X-Mailer: git-send-email 1.7.9.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, These patches try to support multi virtual queues(multi-vq) in one virtio-blk device, and maps each virtual queue(vq) to blk-mq's hardware queue. With this approach, both scalability and performance on virtio-blk device can get improved. For verifying the improvement, I implements virtio-blk multi-vq over qemu's dataplane feature, and both handling host notification from each vq and processing host I/O are still kept in the per-device iothread context, the change is based on qemu v2.0.0 release, and can be accessed from below tree: git://kernel.ubuntu.com/ming/qemu.git #v2.0.0-virtblk-mq.1 For enabling the multi-vq feature, 'num_queues=N' need to be added into '-device virtio-blk-pci ...' of qemu command line, and suggest to pass 'vectors=N+1' to keep one MSI irq vector per each vq, and the feature depends on x-data-plane. Fio(libaio, randread, iodepth=64, bs=4K, jobs=N) is run inside VM to verify the improvement. I just create a small quadcore VM and run fio inside the VM, and num_queues of the virtio-blk device is set as 2, but looks the improvement is still obvious. 1), about scalability - without mutli-vq feature -- jobs=2, thoughput: 145K iops -- jobs=4, thoughput: 100K iops - with mutli-vq feature -- jobs=2, thoughput: 186K iops -- jobs=4, thoughput: 199K iops 2), about thoughput - without mutli-vq feature -- top thoughput: 145K iops - with mutli-vq feature -- top thoughput: 199K iops So in my test, even for a quad-core VM, if the virtqueue number is increased from 1 to 2, both scalability and performance can get improved a lot. V1: - remove RFC since no one objects - add '__u8 unused' for pending as suggested by Rusty - use virtio_cread_feature() directly, suggested by Rusty Thanks, -- Ming Lei