From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [RFC PATCH net-next 3/6] virtio-net: small optimization on free_old_xmit_skbs() Date: Wed, 15 Oct 2014 02:36:04 -0700 Message-ID: <1413365764.12304.54.camel@edumazet-glaptop2.roam.corp.google.com> References: <1413357930-45302-1-git-send-email-jasowang@redhat.com> <1413357930-45302-4-git-send-email-jasowang@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: mst@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, davem@davemloft.net To: Jason Wang Return-path: In-Reply-To: <1413357930-45302-4-git-send-email-jasowang@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org List-Id: netdev.vger.kernel.org On Wed, 2014-10-15 at 15:25 +0800, Jason Wang wrote: > Accumulate the sent packets and sent bytes in local variables and perform a > single u64_stats_update_begin/end() after. > > Cc: Rusty Russell > Cc: Michael S. Tsirkin > Signed-off-by: Jason Wang > --- > drivers/net/virtio_net.c | 12 ++++++++---- > 1 files changed, 8 insertions(+), 4 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 3d0ce44..a4d56b8 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -833,17 +833,21 @@ static void free_old_xmit_skbs(struct send_queue *sq) > unsigned int len; > struct virtnet_info *vi = sq->vq->vdev->priv; > struct virtnet_stats *stats = this_cpu_ptr(vi->stats); > + u64 tx_bytes = 0, tx_packets = 0; > > while ((skb = virtqueue_get_buf(sq->vq, &len)) != NULL) { > pr_debug("Sent skb %p\n", skb); > > - u64_stats_update_begin(&stats->tx_syncp); > - stats->tx_bytes += skb->len; > - stats->tx_packets++; > - u64_stats_update_end(&stats->tx_syncp); > + tx_bytes += skb->len; > + tx_packets++; > > dev_kfree_skb_any(skb); > } > + > + u64_stats_update_begin(&stats->tx_syncp); > + stats->tx_bytes += tx_bytes; > + stats->tx_packets =+ tx_packets; stats->tx_packets += tx_packets; > + u64_stats_update_end(&stats->tx_syncp); > } > > static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)