Re: [dpdk-dev] [PATCH] i40e: fix oversize packet counter not incrementing for large packets

["Wu, Jingjing" <jingjing.wu@intel.com>]

> -----Original Message-----
> From: Michael Bieniek [mailto:michaelbieniekdpdk@gmail.com]
> Sent: Saturday, November 26, 2016 2:21 AM
> To: Zhang, Helin <helin.zhang@intel.com>; Wu, Jingjing <jingjing.wu@intel.com>
> Cc: dev@dpdk.org; Michael Bieniek <michaelbieniekdpdk@gmail.com>
> Subject: [PATCH] i40e: fix oversize packet counter not incrementing for large
> packets
> 
> The XL710 requires that the Set MAC Config command be used to define the
> maximum frame size in order for the Receive Oversize Count register
> (GLPRT_ROC) to be incremented for packets received that are greater than the
> MTU. Without this change, the XL710 will drop the oversized packets without
> incrementing the corresponding counter.
> 
> Signed-off-by: Michael Bieniek <michaelbieniekdpdk@gmail.com>
> ---
>  drivers/net/i40e/i40e_ethdev.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/net/i40e/i40e_ethdev.c b/drivers/net/i40e/i40e_ethdev.c
> index 67778ba..c11c80b 100644
> --- a/drivers/net/i40e/i40e_ethdev.c
> +++ b/drivers/net/i40e/i40e_ethdev.c
> @@ -9709,6 +9709,7 @@ static int
>  i40e_dev_mtu_set(struct rte_eth_dev *dev, uint16_t mtu)  {
>  	struct i40e_pf *pf = I40E_DEV_PRIVATE_TO_PF(dev->data-
> >dev_private);
> +	struct i40e_hw *hw = I40E_DEV_PRIVATE_TO_HW(dev->data-
> >dev_private);
>  	struct rte_eth_dev_data *dev_data = pf->dev_data;
>  	uint32_t frame_size = mtu + ETHER_HDR_LEN
>  			      + ETHER_CRC_LEN + I40E_VLAN_TAG_SIZE; @@ -
> 9732,6 +9733,7 @@ i40e_dev_mtu_set(struct rte_eth_dev *dev, uint16_t mtu)
>  		dev_data->dev_conf.rxmode.jumbo_frame = 0;
> 
>  	dev_data->dev_conf.rxmode.max_rx_pkt_len = frame_size;
> +	i40e_aq_set_mac_config(hw, frame_size, TRUE, 0, NULL);
> 
>  	return ret;
>  }

If you look into the eth_i40e_dev_init, you will find the mac's maximum frame size
Has been set to I40E_FRAME_SIZE_MAX (0x2600). Then the changing of maximum
frame size is by the setting in queues.

If change the frame size on mac, the maximum frame size will not only works on
PF but also VF. 

Thanks
Jingjing