We don't stop rx polling socket during rx processing, this will lead
unnecessary wakeups from under layer net devices (E.g
sock_def_readable() form tun). Rx will be slowed down in this
way. This patch avoids this by stop polling socket during rx
processing. A small drawback is that this introduces some overheads in
light load case because of the extra start/stop polling, but single
netperf TCP_RR does not notice any change. In a super heavy load case,
e.g using pktgen to inject packet to guest, we get about ~8.8%
improvement on pps:
before: ~1240000 pkt/s
after: ~1350000 pkt/s
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
drivers/vhost/net.c | 56 +++++++++++++++++++++++++++--------------------------
1 file changed, 29 insertions(+), 27 deletions(-)
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 10ff494..e91603b 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -301,6 +301,32 @@ static bool vhost_can_busy_poll(struct vhost_dev *dev,
!vhost_has_work(dev);
}
+static void vhost_net_disable_vq(struct vhost_net *n,
+ struct vhost_virtqueue *vq)
+{
+ struct vhost_net_virtqueue *nvq =
+ container_of(vq, struct vhost_net_virtqueue, vq);
+ struct vhost_poll *poll = n->poll + (nvq - n->vqs);
+ if (!vq->private_data)
+ return;
+ vhost_poll_stop(poll);
+}
+
+static int vhost_net_enable_vq(struct vhost_net *n,
+ struct vhost_virtqueue *vq)
+{
+ struct vhost_net_virtqueue *nvq =
+ container_of(vq, struct vhost_net_virtqueue, vq);
+ struct vhost_poll *poll = n->poll + (nvq - n->vqs);
+ struct socket *sock;
+
+ sock = vq->private_data;
+ if (!sock)
+ return 0;
+
+ return vhost_poll_start(poll, sock->file);
+}
+
static int vhost_net_tx_get_vq_desc(struct vhost_net *net,
struct vhost_virtqueue *vq,
struct iovec iov[], unsigned int iov_size,
@@ -627,6 +653,7 @@ static void handle_rx(struct vhost_net *net)
if (!sock)
goto out;
vhost_disable_notify(&net->dev, vq);
+ vhost_net_disable_vq(net, vq);
vhost_hlen = nvq->vhost_hlen;
sock_hlen = nvq->sock_hlen;
@@ -715,9 +742,10 @@ static void handle_rx(struct vhost_net *net)
total_len += vhost_len;
if (unlikely(total_len >= VHOST_NET_WEIGHT)) {
vhost_poll_queue(&vq->poll);
- break;
+ goto out;
}
}
+ vhost_net_enable_vq(net, vq);
out:
mutex_unlock(&vq->mutex);
}
@@ -796,32 +824,6 @@ static int vhost_net_open(struct inode *inode, struct file *f)
return 0;
}
-static void vhost_net_disable_vq(struct vhost_net *n,
- struct vhost_virtqueue *vq)
-{
- struct vhost_net_virtqueue *nvq =
- container_of(vq, struct vhost_net_virtqueue, vq);
- struct vhost_poll *poll = n->poll + (nvq - n->vqs);
- if (!vq->private_data)
- return;
- vhost_poll_stop(poll);
-}
-
-static int vhost_net_enable_vq(struct vhost_net *n,
- struct vhost_virtqueue *vq)
-{
- struct vhost_net_virtqueue *nvq =
- container_of(vq, struct vhost_net_virtqueue, vq);
- struct vhost_poll *poll = n->poll + (nvq - n->vqs);
- struct socket *sock;
-
- sock = vq->private_data;
- if (!sock)
- return 0;
-
- return vhost_poll_start(poll, sock->file);
-}
-
static struct socket *vhost_net_stop_vq(struct vhost_net *n,
struct vhost_virtqueue *vq)
{
--
1.8.3.1
--
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