From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52780) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WHSaR-0005uN-B3 for qemu-devel@nongnu.org; Sun, 23 Feb 2014 01:30:57 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WHSaL-0001Su-6S for qemu-devel@nongnu.org; Sun, 23 Feb 2014 01:30:51 -0500 Received: from mx1.redhat.com ([209.132.183.28]:33529) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WHSaK-0001Si-TS for qemu-devel@nongnu.org; Sun, 23 Feb 2014 01:30:45 -0500 Date: Sun, 23 Feb 2014 08:34:45 +0200 From: "Michael S. Tsirkin" Message-ID: <20140223063445.GB10908@redhat.com> References: <1392958857-10965-1-git-send-email-jasowang@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1392958857-10965-1-git-send-email-jasowang@redhat.com> Subject: Re: [Qemu-devel] [PATCH] virtio-net: calculate proper msix vectors on init List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jason Wang Cc: Paolo Bonzini , qemu-devel@nongnu.org, aliguori@amazon.com On Fri, Feb 21, 2014 at 01:00:57PM +0800, Jason Wang wrote: > Currently, the default msix vectors for virtio-net-pci is 3 which is > obvious not suitable for multiqueue guest, so we depends on the user > or management tools to pass a correct vectors parameter. In fact, we > can simplifying this by calculate the number of vectors on init. > > Consider we have N queues, the number of vectors needed is 2*N + 2 > (plus one config interrupt and control vq). We didn't check whether or > not host support control vq because it was added unconditionally by > qemu to avoid breaking legacy guests such as Minix. > > Cc: Paolo Bonzini > Cc: Michael S. Tsirkin > Signed-off-by: Jason Wang > --- > hw/virtio/virtio-pci.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c > index 7b91841..1dec491 100644 > --- a/hw/virtio/virtio-pci.c > +++ b/hw/virtio/virtio-pci.c > @@ -1416,7 +1416,8 @@ static const TypeInfo virtio_serial_pci_info = { > static Property virtio_net_properties[] = { > DEFINE_PROP_BIT("ioeventfd", VirtIOPCIProxy, flags, > VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT, false), > - DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 3), > + DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, > + DEV_NVECTORS_UNSPECIFIED), > DEFINE_VIRTIO_NET_FEATURES(VirtIOPCIProxy, host_features), > DEFINE_NIC_PROPERTIES(VirtIONetPCI, vdev.nic_conf), > DEFINE_VIRTIO_NET_PROPERTIES(VirtIONetPCI, vdev.net_conf), > @@ -1428,6 +1429,13 @@ static int virtio_net_pci_init(VirtIOPCIProxy *vpci_dev) > DeviceState *qdev = DEVICE(vpci_dev); > VirtIONetPCI *dev = VIRTIO_NET_PCI(vpci_dev); > DeviceState *vdev = DEVICE(&dev->vdev); > + VirtIONet *net = VIRTIO_NET(&dev->vdev); > + > + if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) { > + vpci_dev->nvectors = 2 * MAX(net->nic_conf.queues, 1) + 2; > + } > + > + fprintf(stderr, "vectors is %d\n", vpci_dev->nvectors); last lin shouldn't be there obviously. > > virtio_net_set_config_size(&dev->vdev, vpci_dev->host_features); > virtio_net_set_netclient_name(&dev->vdev, qdev->id, > -- > 1.8.3.2