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[Qemu-devel] [PATCH V4 16/19] virtio-pci: speedup MSI-X masking and unma
From: |
Jason Wang |
Subject: |
[Qemu-devel] [PATCH V4 16/19] virtio-pci: speedup MSI-X masking and unmasking |
Date: |
Wed, 18 Mar 2015 17:35:06 +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: 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 c38f33f..9a5242a 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -632,28 +632,30 @@ 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;
}
@@ -662,16 +664,16 @@ 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
- [Qemu-devel] [PATCH V4 09/19] virito: introduce bus specific queue limit, (continued)
- [Qemu-devel] [PATCH V4 09/19] virito: introduce bus specific queue limit, Jason Wang, 2015/03/18
- [Qemu-devel] [PATCH V4 11/19] virtio-s390: switch to bus specific queue limit, Jason Wang, 2015/03/18
- [Qemu-devel] [PATCH V4 13/19] virtio-pci: switch to use bus specific queue limit, Jason Wang, 2015/03/18
- [Qemu-devel] [PATCH V4 12/19] virtio-mmio: switch to bus specific queue limit, Jason Wang, 2015/03/18
- [Qemu-devel] [PATCH V4 14/19] virtio: introduce vector to virtqueues mapping, Jason Wang, 2015/03/18
- [Qemu-devel] [PATCH V4 16/19] virtio-pci: speedup MSI-X masking and unmasking,
Jason Wang <=
- [Qemu-devel] [PATCH V4 15/19] virtio: introduce virtio_queue_get_index(), Jason Wang, 2015/03/18
- [Qemu-devel] [PATCH V4 17/19] virtio-pci: increase the maximum number of virtqueues to 513, Jason Wang, 2015/03/18
- [Qemu-devel] [PATCH V4 18/19] pci: remove hard-coded bar size in msix_init_exclusive_bar(), Jason Wang, 2015/03/18
[Qemu-devel] [PATCH V4 19/19] virtio-pci: introduce auto_msix_bar_size property, Jason Wang, 2015/03/18