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From faa5a68c3133624759bc7e36714fd6629bcd00d8 Mon Sep 17 00:00:00 2001
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From: Xiao Wang <jasowang@redhat.com>
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Date: Thu, 18 Jun 2015 06:11:45 +0200
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Subject: [PATCH 024/217] virtio-pci: speedup MSI-X masking and unmasking
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Message-id: <1434607916-15166-10-git-send-email-jasowang@redhat.com>
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Patchwork-id: 66307
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O-Subject: [RHEL7.2 qemu-kvm-rhev PATCH 09/20] virtio-pci: speedup MSI-X masking and unmasking
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Bugzilla: 1231610
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: Vlad Yasevich <vyasevic@redhat.com>
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RH-Acked-by: Michael S. Tsirkin <mst@redhat.com>
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This patch tries to speed up the MSI-X masking and unmasking through
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the mapping between vector and queues. With this patch it will there's
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no need to go through all possible virtqueues, which may help to
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reduce the time spent when doing MSI-X masking/unmasking a single
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vector when more than hundreds or even thousands of virtqueues were
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supported.
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Tested with 80 queue pairs virito-net-pci by changing the smp affinity
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in the background and doing netperf in the same time:
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Before the patch:
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5711.70 Gbits/sec
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After the patch:
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6830.98 Gbits/sec
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About 19.6% improvements in throughput.
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Cc: Michael S. Tsirkin <mst@redhat.com>
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Signed-off-by: Jason Wang <jasowang@redhat.com>
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Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
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Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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(cherry picked from commit 851c2a75a6e80c8aa5e713864d98cfb512e7229b)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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hw/virtio/virtio-pci.c | 40 +++++++++++++++++++++-------------------
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1 file changed, 21 insertions(+), 19 deletions(-)
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diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
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index 6b064b9..b91e799 100644
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--- a/hw/virtio/virtio-pci.c
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+++ b/hw/virtio/virtio-pci.c
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@@ -630,28 +630,30 @@ static int virtio_pci_vector_unmask(PCIDevice *dev, unsigned vector,
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{
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VirtIOPCIProxy *proxy = container_of(dev, VirtIOPCIProxy, pci_dev);
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VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
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- int ret, queue_no;
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+ VirtQueue *vq = virtio_vector_first_queue(vdev, vector);
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+ int ret, index, unmasked = 0;
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- for (queue_no = 0; queue_no < proxy->nvqs_with_notifiers; queue_no++) {
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- if (!virtio_queue_get_num(vdev, queue_no)) {
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+ while (vq) {
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+ index = virtio_get_queue_index(vq);
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+ if (!virtio_queue_get_num(vdev, index)) {
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break;
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}
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- if (virtio_queue_vector(vdev, queue_no) != vector) {
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- continue;
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- }
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- ret = virtio_pci_vq_vector_unmask(proxy, queue_no, vector, msg);
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+ ret = virtio_pci_vq_vector_unmask(proxy, index, vector, msg);
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if (ret < 0) {
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goto undo;
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}
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+ vq = virtio_vector_next_queue(vq);
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+ ++unmasked;
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}
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+
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return 0;
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undo:
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- while (--queue_no >= 0) {
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- if (virtio_queue_vector(vdev, queue_no) != vector) {
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- continue;
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- }
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- virtio_pci_vq_vector_mask(proxy, queue_no, vector);
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+ vq = virtio_vector_first_queue(vdev, vector);
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+ while (vq && --unmasked >= 0) {
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+ index = virtio_get_queue_index(vq);
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+ virtio_pci_vq_vector_mask(proxy, index, vector);
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+ vq = virtio_vector_next_queue(vq);
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}
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return ret;
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}
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@@ -660,16 +662,16 @@ static void virtio_pci_vector_mask(PCIDevice *dev, unsigned vector)
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{
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VirtIOPCIProxy *proxy = container_of(dev, VirtIOPCIProxy, pci_dev);
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VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
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- int queue_no;
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+ VirtQueue *vq = virtio_vector_first_queue(vdev, vector);
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+ int index;
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- for (queue_no = 0; queue_no < proxy->nvqs_with_notifiers; queue_no++) {
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- if (!virtio_queue_get_num(vdev, queue_no)) {
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+ while (vq) {
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+ index = virtio_get_queue_index(vq);
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+ if (!virtio_queue_get_num(vdev, index)) {
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break;
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}
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- if (virtio_queue_vector(vdev, queue_no) != vector) {
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- continue;
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- }
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- virtio_pci_vq_vector_mask(proxy, queue_no, vector);
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+ virtio_pci_vq_vector_mask(proxy, index, vector);
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+ vq = virtio_vector_next_queue(vq);
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}
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}
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--
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1.8.3.1
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