Re: [dpdk-dev] [PATCH v3 0/3] enhance TX checksum command and csum forwarding engine

["Liu, Jijiang" <jijiang.liu@intel.com>]

Hi Olivier,

> -----Original Message-----
> From: Olivier MATZ [mailto:olivier.matz@6wind.com]
> Sent: Saturday, December 13, 2014 12:33 AM
> To: Liu, Jijiang
> Cc: dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v3 0/3] enhance TX checksum command and
> csum forwarding engine
>
> Hello,
>
> On 12/12/2014 04:48 AM, Liu, Jijiang wrote:
> > The 'hw/sw' option  is used to set/clear the flag of enabling TX tunneling packet
> checksum hardware offload in testpmd application.
>
> This is not clear at all.
> In your command, there is (hw|sw|none).
> Are you talking about inner or outer?
> Is this command useful for any kind of packet?
> How does it combine with "tx_checksum set outer-ip (hw|sw)"?
>

I rethink these TX checksum commands in this patch set and agree with you that we should make some changes for having clear meaning for them.

There are  3 commands in patch set as follows,
1. tx_checksum set tunnel (hw|sw|none) (port-id)

Now I also think the command 1 may confuse user, they probably don't understand  why we need 'hw' or 'sw' option and when  to use the two option,
so I will replace the command with 'tx_checksum set hw-tunnel-mode (on|off) (port-id)' command.

2. tx_checksum set outer-ip (hw|sw) (port-id)
3. tx_checksum set  (ip|udp|tcp|sctp) (hw|sw) (port-id)

The command 2 will be merged into command 3, the new command is ' tx_checksum set  (outer-ip|ip|udp|tcp|sctp) (hw|sw) (port-id)'.

These most of the cases in http://dpdk.org/ml/archives/dev/2014-December/009213.html will be covered by using the two commands

The command 'tx_checksum set hw-tunnel-mode (on|off)  (port-id)' is used to set/clear  TESTPMD_TX_OFFLOAD_TUNNEL_CKSUM flag.
Actually, the PKT_TX_UDP_TUNNEL_PKT offload flag will be set if the testpmd flag is set, which tell driver/HW treat  that transmit packet as a tunneling packet.

When 'on' is set, which is able to meet Method B.1 and method C.

When 'off' is set, the TESTPMD_TX_OFFLOAD_TUNNEL_CKSUM is not needed to set, so the PKT_TX_UDP_TUNNEL_PKT offload flag is not needed to set,  then HW treat  that transmit packet as a non-tunneling packet. It is able to meet Method B.2.

As to case A, I think it is not mandatory to cover it in csum fwd engine for tunneling packet.

Is the above description clear for you?

> Regards,
> Olivier