From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56898) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Yrn7m-0002FD-B5 for qemu-devel@nongnu.org; Mon, 11 May 2015 08:47:59 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Yrn7l-0002SJ-38 for qemu-devel@nongnu.org; Mon, 11 May 2015 08:47:58 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38965) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Yrn7k-0002SC-RJ for qemu-devel@nongnu.org; Mon, 11 May 2015 08:47:57 -0400 Date: Mon, 11 May 2015 14:47:52 +0200 From: "Michael S. Tsirkin" Message-ID: <1431329108-2605-14-git-send-email-mst@redhat.com> References: <1431329108-2605-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1431329108-2605-1-git-send-email-mst@redhat.com> Subject: [Qemu-devel] [PULL 13/28] virtio-pci: speedup MSI-X masking and unmasking List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Peter Maydell , Jason Wang From: Jason Wang This patch tries to speed up the MSI-X masking and unmasking through the mapping between vector and queues. With this patch it will there's no need to go through all possible virtqueues, which may help to reduce the time spent when doing MSI-X masking/unmasking a single vector when more than hundreds or even thousands of virtqueues were supported. Tested with 80 queue pairs virito-net-pci by changing the smp affinity in the background and doing netperf in the same time: Before the patch: 5711.70 Gbits/sec After the patch: 6830.98 Gbits/sec About 19.6% improvements in throughput. Cc: Michael S. Tsirkin Signed-off-by: Jason Wang Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/virtio/virtio-pci.c | 40 +++++++++++++++++++++------------------- 1 file changed, 21 insertions(+), 19 deletions(-) diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c index 6ae24a0..5ea4656 100644 --- a/hw/virtio/virtio-pci.c +++ b/hw/virtio/virtio-pci.c @@ -630,28 +630,30 @@ static int virtio_pci_vector_unmask(PCIDevice *dev, unsigned vector, { VirtIOPCIProxy *proxy = container_of(dev, VirtIOPCIProxy, pci_dev); VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus); - int ret, queue_no; + VirtQueue *vq = virtio_vector_first_queue(vdev, vector); + int ret, index, unmasked = 0; - for (queue_no = 0; queue_no < proxy->nvqs_with_notifiers; queue_no++) { - if (!virtio_queue_get_num(vdev, queue_no)) { + while (vq) { + index = virtio_get_queue_index(vq); + if (!virtio_queue_get_num(vdev, index)) { break; } - if (virtio_queue_vector(vdev, queue_no) != vector) { - continue; - } - ret = virtio_pci_vq_vector_unmask(proxy, queue_no, vector, msg); + ret = virtio_pci_vq_vector_unmask(proxy, index, vector, msg); if (ret < 0) { goto undo; } + vq = virtio_vector_next_queue(vq); + ++unmasked; } + return 0; undo: - while (--queue_no >= 0) { - if (virtio_queue_vector(vdev, queue_no) != vector) { - continue; - } - virtio_pci_vq_vector_mask(proxy, queue_no, vector); + vq = virtio_vector_first_queue(vdev, vector); + while (vq && --unmasked >= 0) { + index = virtio_get_queue_index(vq); + virtio_pci_vq_vector_mask(proxy, index, vector); + vq = virtio_vector_next_queue(vq); } return ret; } @@ -660,16 +662,16 @@ static void virtio_pci_vector_mask(PCIDevice *dev, unsigned vector) { VirtIOPCIProxy *proxy = container_of(dev, VirtIOPCIProxy, pci_dev); VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus); - int queue_no; + VirtQueue *vq = virtio_vector_first_queue(vdev, vector); + int index; - for (queue_no = 0; queue_no < proxy->nvqs_with_notifiers; queue_no++) { - if (!virtio_queue_get_num(vdev, queue_no)) { + while (vq) { + index = virtio_get_queue_index(vq); + if (!virtio_queue_get_num(vdev, index)) { break; } - if (virtio_queue_vector(vdev, queue_no) != vector) { - continue; - } - virtio_pci_vq_vector_mask(proxy, queue_no, vector); + virtio_pci_vq_vector_mask(proxy, index, vector); + vq = virtio_vector_next_queue(vq); } } -- MST