From mboxrd@z Thu Jan 1 00:00:00 1970 From: Willem de Bruijn Subject: [PATCH net-next 3/3] virtio-net: clean tx descriptors from rx napi Date: Sun, 2 Apr 2017 16:10:12 -0400 Message-ID: <20170402201012.76473-4-willemdebruijn.kernel@gmail.com> References: <20170402201012.76473-1-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-qt0-f196.google.com ([209.85.216.196]:33981 "EHLO mail-qt0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751704AbdDBUKS (ORCPT ); Sun, 2 Apr 2017 16:10:18 -0400 Received: by mail-qt0-f196.google.com with SMTP id x35so16535611qtc.1 for ; Sun, 02 Apr 2017 13:10:18 -0700 (PDT) In-Reply-To: <20170402201012.76473-1-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 | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 95d938e82080..af830eb212bf 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1030,12 +1030,34 @@ static int virtnet_receive(struct receive_queue *rq, int budget) return received; } +static void free_old_xmit_skbs(struct send_queue *sq); + +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; + + __netif_tx_lock(txq, smp_processor_id()); + free_old_xmit_skbs(sq); + __netif_tx_unlock(txq); + + if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS) + netif_wake_subqueue(vi->dev, vq2txq(sq->vq)); +} + 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? */ -- 2.12.2.564.g063fe858b8-goog