diff options
| author | ? jiang <jiangkidd@hotmail.com> | 2019-08-20 02:51:23 +0000 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2019-09-04 06:21:17 -0400 |
| commit | 718be6bab26fb01fa0147a2b614a3eefd96a2957 (patch) | |
| tree | 1b11a31a2ef6a4afede5b6fe723ebe00b5670ab5 | |
| parent | 264b563b8675771834419057cbe076c1a41fb666 (diff) | |
virtio-net: lower min ring num_free for efficiency
This change lowers ring buffer reclaim threshold from 1/2*queue to budget
for better performance. According to our test with qemu + dpdk, packet
dropping happens when the guest is not able to provide free buffer in
avail ring timely with default 1/2*queue. The value in the patch has been
tested and does show better performance.
Test setup: iperf3 to generate packets to guest (total 30mins, pps 400k, UDP)
avg packets drop before: 2842
avg packets drop after: 360(-87.3%)
Further, current code suffers from a starvation problem: the amount of
work done by try_fill_recv is not bounded by the budget parameter, thus
(with large queues) once in a while userspace gets blocked for a long
time while queue is being refilled. Trigger refills earlier to make sure
the amount of work to do is limited.
Signed-off-by: jiangkidd <jiangkidd@hotmail.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
| -rw-r--r-- | drivers/net/virtio_net.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 4f3de0ac8b0b..ba98e0971b84 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1331,7 +1331,7 @@ static int virtnet_receive(struct receive_queue *rq, int budget, } } - if (rq->vq->num_free > virtqueue_get_vring_size(rq->vq) / 2) { + if (rq->vq->num_free > min((unsigned int)budget, virtqueue_get_vring_size(rq->vq)) / 2) { if (!try_fill_recv(vi, rq, GFP_ATOMIC)) schedule_delayed_work(&vi->refill, 0); } |