Re: [dpdk-dev] [PATCH] net/virtio: fix wrong TX pkt length stats

[Yuanhan Liu <yliu@fridaylinux.org>]

On Wed, Oct 11, 2017 at 12:39:35PM +0800, Zhiyong Yang wrote:
> In the function virtqueue_enqueue_xmit(), when can_push == 1 is true,
> vtnet_hdr_size is added to pkt_len by calling rte_pktmbuf_prepend.
> So, virtio header len should be subtracted before calling stats
> function.

Nice catch!

> Fixes: 58169a9c8153 ("net/virtio: support Tx checksum offload")

It should also Cc stable.

> Signed-off-by: Zhiyong Yang <zhiyong.yang@intel.com>
> ---
>  drivers/net/virtio/virtio_rxtx.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
> index 609b4138a..bf14f9a99 100644
> --- a/drivers/net/virtio/virtio_rxtx.c
> +++ b/drivers/net/virtio/virtio_rxtx.c
> @@ -1079,6 +1079,12 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
>  		/* Enqueue Packet buffers */
>  		virtqueue_enqueue_xmit(txvq, txm, slots, use_indirect, can_push);
>  
> +		/* In function virtqueue_enqueue_xmit(), when can_push == 1

Hmm..., why not modifying it directly in virtqueue_enqueue_xmit()?

	--yliu

> +		 * is true, vtnet_hdr_size is added to pkt_len of mbuf. So, it
> +		 * should be subtracted before calling stats function.
> +		 */
> +		if (can_push == 1)
> +			txm->pkt_len -= txvq->vq->hw->vtnet_hdr_size;
>  		txvq->stats.bytes += txm->pkt_len;
>  		virtio_update_packet_stats(&txvq->stats, txm);
>  	}
> -- 
> 2.13.3