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[Qemu-devel] [PATCH V3 11/14] virtio-pci: speedup MSI-X masking and unma
From: |
Jason Wang |
Subject: |
[Qemu-devel] [PATCH V3 11/14] virtio-pci: speedup MSI-X masking and unmasking |
Date: |
Thu, 5 Mar 2015 13:48:48 +0800 |
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: Anthony Liguori <address@hidden>
Cc: Michael S. Tsirkin <address@hidden>
Signed-off-by: Jason Wang <address@hidden>
---
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 280bba2..327a3fc 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -676,28 +676,30 @@ 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_queue_get_index(vdev, 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_queue_get_index(vdev, vq);
+ virtio_pci_vq_vector_mask(proxy, index, vector);
+ vq = virtio_vector_next_queue(vq);
}
return ret;
}
@@ -706,16 +708,16 @@ 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_queue_get_index(vdev, 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);
}
}
--
2.1.0
- Re: [Qemu-devel] [PATCH V3 06/14] virtio-serial-bus: switch to bus specific queue limit, (continued)
[Qemu-devel] [PATCH V3 07/14] virtio-mmio: switch to bus specific queue limit, Jason Wang, 2015/03/05
[Qemu-devel] [PATCH V3 09/14] virtio: introduce vector to virtqueues mapping, Jason Wang, 2015/03/05
[Qemu-devel] [PATCH V3 11/14] virtio-pci: speedup MSI-X masking and unmasking,
Jason Wang <=
[Qemu-devel] [PATCH V3 10/14] virtio: introduce virtio_queue_get_index(), Jason Wang, 2015/03/05
[Qemu-devel] [PATCH V3 12/14] virtio-pci: increase the maximum number of virtqueues to 513, Jason Wang, 2015/03/05
[Qemu-devel] [PATCH V3 14/14] virtio-pci: introduce auto_msix_bar_size property, Jason Wang, 2015/03/05
[Qemu-devel] [PATCH V3 13/14] pci: remove hard-coded bar size in msix_init_exclusive_bar(), Jason Wang, 2015/03/05
Re: [Qemu-devel] [PATCH V3 00/14] Support more virtio queues, Michael S. Tsirkin, 2015/03/12