Commit bdb12e0d authored Apr 24, 2017 by Willem de Bruijn Committed by David S. Miller Apr 24, 2017

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 <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 7b0411ef

drivers/net/virtio_net.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -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);

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