From faa5a68c3133624759bc7e36714fd6629bcd00d8 Mon Sep 17 00:00:00 2001 From: Xiao Wang Date: Thu, 18 Jun 2015 06:11:45 +0200 Subject: [PATCH 024/217] virtio-pci: speedup MSI-X masking and unmasking Message-id: <1434607916-15166-10-git-send-email-jasowang@redhat.com> Patchwork-id: 66307 O-Subject: [RHEL7.2 qemu-kvm-rhev PATCH 09/20] virtio-pci: speedup MSI-X masking and unmasking Bugzilla: 1231610 RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Vlad Yasevich RH-Acked-by: Michael S. Tsirkin 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 (cherry picked from commit 851c2a75a6e80c8aa5e713864d98cfb512e7229b) Signed-off-by: Miroslav Rezanina --- 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 6b064b9..b91e799 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); } } -- 1.8.3.1