From mboxrd@z Thu Jan 1 00:00:00 1970 From: Willem de Bruijn Subject: [PATCH net-next v2 4/5] virtio-net: clean tx descriptors from rx napi Date: Tue, 18 Apr 2017 16:21:07 -0400 Message-ID: <20170418202108.61920-5-willemdebruijn.kernel@gmail.com> References: <20170418202108.61920-1-willemdebruijn.kernel@gmail.com> Cc: mst@redhat.com, jasowang@redhat.com, virtualization@lists.linux-foundation.org, davem@davemloft.net, Willem de Bruijn To: netdev@vger.kernel.org Return-path: Received: from mail-qk0-f195.google.com ([209.85.220.195]:34018 "EHLO mail-qk0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754281AbdDRUVO (ORCPT ); Tue, 18 Apr 2017 16:21:14 -0400 Received: by mail-qk0-f195.google.com with SMTP id p68so639131qke.1 for ; Tue, 18 Apr 2017 13:21:13 -0700 (PDT) In-Reply-To: <20170418202108.61920-1-willemdebruijn.kernel@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Willem de Bruijn 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 --- 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 81a98de864e6..b14c82ce0032 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1072,12 +1072,33 @@ 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? */ -- 2.12.2.816.g2cccc81164-goog