From 7b0411ef4aa69c9256d6a2c289d0a2b320414633 Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Mon, 24 Apr 2017 13:49:29 -0400 Subject: [PATCH] virtio-net: clean tx descriptors from rx napi Amortize the cost of virtual interrupts by doing both rx and tx work on reception of a receive interrupt if tx napi is enabled. With VIRTIO_F_EVENT_IDX, this suppresses most explicit tx completion interrupts for bidirectional workloads. Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller --- drivers/net/virtio_net.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 4ec79e5d7a86..9dd978f34c1f 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1075,12 +1075,33 @@ static void free_old_xmit_skbs(struct send_queue *sq) u64_stats_update_end(&stats->tx_syncp); } +static void virtnet_poll_cleantx(struct receive_queue *rq) +{ + struct virtnet_info *vi = rq->vq->vdev->priv; + unsigned int index = vq2rxq(rq->vq); + struct send_queue *sq = &vi->sq[index]; + struct netdev_queue *txq = netdev_get_tx_queue(vi->dev, index); + + if (!sq->napi.weight) + return; + + if (__netif_tx_trylock(txq)) { + free_old_xmit_skbs(sq); + __netif_tx_unlock(txq); + } + + if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS) + netif_tx_wake_queue(txq); +} + static int virtnet_poll(struct napi_struct *napi, int budget) { struct receive_queue *rq = container_of(napi, struct receive_queue, napi); unsigned int received; + virtnet_poll_cleantx(rq); + received = virtnet_receive(rq, budget); /* Out of packets? */ -- 2.20.1