From mboxrd@z Thu Jan 1 00:00:00 1970 From: Willem de Bruijn Subject: [PATCH net-next v3 5/5] virtio-net: keep tx interrupts disabled unless kick Date: Mon, 24 Apr 2017 13:49:30 -0400 Message-ID: <20170424174930.82623-6-willemdebruijn.kernel@gmail.com> References: <20170424174930.82623-1-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-f196.google.com ([209.85.220.196]:34986 "EHLO mail-qk0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S976273AbdDXRth (ORCPT ); Mon, 24 Apr 2017 13:49:37 -0400 Received: by mail-qk0-f196.google.com with SMTP id a19so4072210qkg.2 for ; Mon, 24 Apr 2017 10:49:37 -0700 (PDT) In-Reply-To: <20170424174930.82623-1-willemdebruijn.kernel@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Willem de Bruijn 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 --- 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 9dd978f34c1f..003143835766 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); -- 2.12.2.816.g2cccc81164-goog