From bdb12e0d2ffc84a0248788cdf6cfbff86ee34602 Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Mon, 24 Apr 2017 13:49:30 -0400 Subject: [PATCH] virtio-net: keep tx interrupts disabled unless kick Tx napi mode increases the rate of transmit interrupts. Suppress some by masking interrupts while more packets are expected. The interrupts will be reenabled before the last packet is sent. This optimization reduces the througput drop with tx napi for unidirectional flows such as UDP_STREAM that do not benefit from cleaning tx completions in the the receive napi handler. Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller --- drivers/net/virtio_net.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 9dd978f..0031438 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1200,6 +1200,9 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) /* Free up any pending old buffers before queueing new ones. */ free_old_xmit_skbs(sq); + if (use_napi && kick) + virtqueue_enable_cb_delayed(sq->vq); + /* timestamp packet in software */ skb_tx_timestamp(skb); -- 2.7.4