From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754038Ab2GEUDn (ORCPT ); Thu, 5 Jul 2012 16:03:43 -0400 Received: from mx1.redhat.com ([209.132.183.28]:32987 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751383Ab2GEUDl (ORCPT ); Thu, 5 Jul 2012 16:03:41 -0400 Message-ID: <4FF5F2F2.9050307@redhat.com> Date: Fri, 06 Jul 2012 04:02:58 +0800 From: Amos Kong User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20120430 Thunderbird/12.0.1 MIME-Version: 1.0 To: Jason Wang CC: mst@redhat.com, mashirle@us.ibm.com, krkumar2@in.ibm.com, habanero@linux.vnet.ibm.com, rusty@rustcorp.com.au, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, edumazet@google.com, tahm@linux.vnet.ibm.com, jwhan@filewood.snu.ac.kr, davem@davemloft.net, kvm@vger.kernel.org, sri@us.ibm.com Subject: Re: [net-next RFC V5 4/5] virtio_net: multiqueue support References: <1341484194-8108-1-git-send-email-jasowang@redhat.com> <1341484194-8108-5-git-send-email-jasowang@redhat.com> In-Reply-To: <1341484194-8108-5-git-send-email-jasowang@redhat.com> X-Enigmail-Version: 1.5pre OpenPGP: id=39BCFF63 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/05/2012 06:29 PM, Jason Wang wrote: > This patch converts virtio_net to a multi queue device. After negotiated > VIRTIO_NET_F_MULTIQUEUE feature, the virtio device has many tx/rx queue pairs, > and driver could read the number from config space. > > The driver expects the number of rx/tx queue paris is equal to the number of > vcpus. To maximize the performance under this per-cpu rx/tx queue pairs, some > optimization were introduced: > > - Txq selection is based on the processor id in order to avoid contending a lock > whose owner may exits to host. > - Since the txq/txq were per-cpu, affinity hint were set to the cpu that owns > the queue pairs. > > Signed-off-by: Krishna Kumar > Signed-off-by: Jason Wang > --- ... > > static int virtnet_probe(struct virtio_device *vdev) > { > - int err; > + int i, err; > struct net_device *dev; > struct virtnet_info *vi; > + u16 num_queues, num_queue_pairs; > + > + /* Find if host supports multiqueue virtio_net device */ > + err = virtio_config_val(vdev, VIRTIO_NET_F_MULTIQUEUE, > + offsetof(struct virtio_net_config, > + num_queues), &num_queues); > + > + /* We need atleast 2 queue's */ s/atleast/at least/ > + if (err || num_queues < 2) > + num_queues = 2; > + if (num_queues > MAX_QUEUES * 2) > + num_queues = MAX_QUEUES; num_queues = MAX_QUEUES * 2; MAX_QUEUES is the limitation of RX or TX. > + > + num_queue_pairs = num_queues / 2; ... -- Amos.