From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: [RFC PATCH 0/2] block: virtio-blk: support multi vq per virtio-blk Date: Fri, 13 Jun 2014 11:35:15 -0600 Message-ID: <539B3653.6040408@kernel.dk> References: <1402680562-8328-1-git-send-email-ming.lei@canonical.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1402680562-8328-1-git-send-email-ming.lei@canonical.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Ming Lei , linux-kernel@vger.kernel.org Cc: "Michael S. Tsirkin" , linux-api@vger.kernel.org, virtualization@lists.linux-foundation.org, Stefan Hajnoczi , Paolo Bonzini List-Id: linux-api@vger.kernel.org On 06/13/2014 11:29 AM, Ming Lei wrote: > Hi, > > This 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 problems on > virtio-blk device 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 changes are 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-dataplane-mq > > 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 > - without mutli-vq feature > -- jobs=2, thoughput: 186K iops > -- jobs=4, thoughput: 199K iops Awesome! I was hoping someone would do that, and make virtio-blk take full advantage of blk-mq. -- Jens Axboe