From 851c2a75a6e80c8aa5e713864d98cfb512e7229b Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Thu, 23 Apr 2015 14:21:47 +0800 Subject: virtio-pci: speedup MSI-X masking and unmasking 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); } } -- cgit v1.1