Re: [net-next v2] virtio_net: replace netdev_alloc_skb_ip_align() with napi_alloc_skb()
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2016-03-20 12:28:23
On Fri, Mar 18, 2016 at 04:42:48PM +0100, Paolo Abeni wrote:
This gives small but noticeable rx performance improvement (2-3%) and will allow exploiting future napi improvement. Signed-off-by: Paolo Abeni <pabeni@redhat.com>
I am not sure this is necessarily worth doing for this dumb hardware. I queued v1 in vhost tree for now, let's see some performance numbers before we start changing about other paths.
quoted hunk
-- v2: replace also netdev_alloc_skb_ip_align() invocation in add_recvbuf_small(), suggested by Venkatesh Srinivas --- drivers/net/virtio_net.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index fb0eae4..100e039 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c@@ -260,7 +260,7 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, p = page_address(page) + offset; /* copy small packet so we can reuse these pages for small data */ - skb = netdev_alloc_skb_ip_align(vi->dev, GOOD_COPY_LEN); + skb = napi_alloc_skb(&rq->napi, GOOD_COPY_LEN); if (unlikely(!skb)) return NULL;@@ -541,7 +541,7 @@ static int add_recvbuf_small(struct virtnet_info *vi, struct receive_queue *rq, struct virtio_net_hdr_mrg_rxbuf *hdr; int err; - skb = __netdev_alloc_skb_ip_align(vi->dev, GOOD_PACKET_LEN, gfp); + skb = __napi_alloc_skb(&rq->napi, GOOD_PACKET_LEN, gfp); if (unlikely(!skb)) return -ENOMEM;-- 1.8.3.1