[dpdk-dev] [PATCH v8 10/10] app/testpmd:test VxLAN Tx checksum offload

[Liu, Jijiang]

> -----Original Message-----
> From: Olivier MATZ [mailto:olivier.matz at 6wind.com]
> Sent: Wednesday, November 5, 2014 6:28 PM
> To: Liu, Jijiang
> Cc: dev at dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v8 10/10] app/testpmd:test VxLAN Tx checksum
> offload
> 
> Hi Jijiang,
> 
> Thank you for your answer. Please find some comments below.
> 
> 
> Another thing is surprising me.
> 
> - if PKT_TX_VXLAN_CKSUM is not set (legacy use case), then the
>    driver use l2_len and l3_len to offload inner IP/UDP/TCP checksums.
If the flag is not set, and imply that it is not VXLAN packet, 
 and do TX checksum offload as regular packet.

> - if PKT_TX_VXLAN_CKSUM is set, then the driver has to use
>    inner_l{23}_len instead of l{23}_len for the same operation.
Your understanding is not fully correct.
The l{23}_len is still used for TX checksum offload, please refer to i40e_txd_enable_checksum()  implementation.


> Adding PKT_TX_VXLAN_CKSUM changes the semantic of l2_len and l3_len.
> To fix this, I suggest to remove the new fields inner_l{23}_len then add
> outer_l{23}_len instead. Therefore, the semantic of l2_len and l3_len would not
> change, and a driver would always use the same field for a specific offload.
Oh...
> For my TSO development, I will follow the current semantic.
For TSO, you still can use l{2,3} _len .
When I develop tunneling TSO, I will use inner_l3_len/inner_l4_len.

>