Messages in this thread Patch in this message | | | From | Jason Wang <> | Subject | [RFC PATCH net-next 6/6] virtio-net: enable tx interrupt only for the final skb in the chain | Date | Wed, 15 Oct 2014 15:25:30 +0800 |
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With the help of xmit_more and virtqueue_enable_cb_avail(), this patch enable tx interrupt only for the final skb in the chain if needed. This will help to mitigate tx interrupts.
Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com> --- drivers/net/virtio_net.c | 10 +++++++--- 1 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 2afc2e2..5943f3f 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -993,12 +993,16 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) virtqueue_disable_cb(sq->vq); } } - } else if (virtqueue_enable_cb(sq->vq)) { - free_old_xmit_skbs(sq, qsize); } - if (__netif_subqueue_stopped(dev, qnum) || !skb->xmit_more) + if (__netif_subqueue_stopped(dev, qnum) || !skb->xmit_more) { virtqueue_kick(sq->vq); + if (sq->vq->num_free >= 2 +MAX_SKB_FRAGS && + unlikely(virtqueue_enable_cb_avail(sq->vq))) { + free_old_xmit_skbs(sq, qsize); + virtqueue_disable_cb(sq->vq); + } + } return NETDEV_TX_OK; } -- 1.7.1
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