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authorJason Wang <jasowang@redhat.com>2016-06-30 14:45:36 +0800
committerDavid S. Miller <davem@davemloft.net>2016-07-01 05:32:17 -0400
commit1576d98605998fb59d121a39581129e134217182 (patch)
tree20949c1b4243a0e746570b3f08483b40c183ae57 /drivers/vhost
parent08294a26e15d7baf1e14ee569e9f2bc82a7ae768 (diff)
downloadlinux-1576d98605998fb59d121a39581129e134217182.tar.bz2
tun: switch to use skb array for tx
We used to queue tx packets in sk_receive_queue, this is less efficient since it requires spinlocks to synchronize between producer and consumer. This patch tries to address this by: - switch from sk_receive_queue to a skb_array, and resize it when tx_queue_len was changed. - introduce a new proto_ops peek_len which was used for peeking the skb length. - implement a tun version of peek_len for vhost_net to use and convert vhost_net to use peek_len if possible. Pktgen test shows about 15.3% improvement on guest receiving pps for small buffers: Before: ~1300000pps After : ~1500000pps Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/vhost')
-rw-r--r--drivers/vhost/net.c16
1 files changed, 15 insertions, 1 deletions
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 1d3e45f84549..e032ca397371 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -481,10 +481,14 @@ out:
static int peek_head_len(struct sock *sk)
{
+ struct socket *sock = sk->sk_socket;
struct sk_buff *head;
int len = 0;
unsigned long flags;
+ if (sock->ops->peek_len)
+ return sock->ops->peek_len(sock);
+
spin_lock_irqsave(&sk->sk_receive_queue.lock, flags);
head = skb_peek(&sk->sk_receive_queue);
if (likely(head)) {
@@ -497,6 +501,16 @@ static int peek_head_len(struct sock *sk)
return len;
}
+static int sk_has_rx_data(struct sock *sk)
+{
+ struct socket *sock = sk->sk_socket;
+
+ if (sock->ops->peek_len)
+ return sock->ops->peek_len(sock);
+
+ return skb_queue_empty(&sk->sk_receive_queue);
+}
+
static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk)
{
struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
@@ -513,7 +527,7 @@ static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk)
endtime = busy_clock() + vq->busyloop_timeout;
while (vhost_can_busy_poll(&net->dev, endtime) &&
- skb_queue_empty(&sk->sk_receive_queue) &&
+ !sk_has_rx_data(sk) &&
vhost_vq_avail_empty(&net->dev, vq))
cpu_relax_lowlatency();