Re: [dpdk-dev] [PATCH v4 3/3] app/testpmd: fix Tx offload on tunneling packet

["Tan, Jianfeng" <jianfeng.tan@intel.com>]

Hi Konstantin,


On 9/19/2016 8:09 PM, Ananyev, Konstantin wrote:
> Hi Jainfeng,
>
>> -----Original Message-----
>> From: Tan, Jianfeng
>> Sent: Monday, August 1, 2016 4:57 AM
>> To: dev@dpdk.org
>> Cc: thomas.monjalon@6wind.com; De Lara Guarch, Pablo <pablo.de.lara.guarch@intel.com>; Ananyev, Konstantin
>> <konstantin.ananyev@intel.com>; Wu, Jingjing <jingjing.wu@intel.com>; Zhang, Helin <helin.zhang@intel.com>; Tan, Jianfeng
>> <jianfeng.tan@intel.com>; Tao, Zhe <zhe.tao@intel.com>
>> Subject: [PATCH v4 3/3] app/testpmd: fix Tx offload on tunneling packet
>>
>> Tx offload on tunneling packet now requires applications to correctly set tunneling type. Without setting it, i40e driver does not parse
>> tunneling parameters. Besides that, add a check to see if NIC supports TSO on tunneling packet when executing "csum parse_tunnel on
>> _port"
>> after "tso set _size _port" or the other way around.
>>
>> Fixes: b51c47536a9e ("app/testpmd: support TSO in checksum forward engine")
>>
>> Signed-off-by: Zhe Tao <zhe.tao@intel.com>
>> Signed-off-by: Jianfeng Tan <jianfeng.tan@intel.com>
>> ---
>>   app/test-pmd/cmdline.c  | 42 ++++++++++++++++++++++++++++++++++++------
>>   app/test-pmd/csumonly.c | 37 +++++++++++++++++++++++++++++--------
>>   2 files changed, 65 insertions(+), 14 deletions(-)
>>
>> [...]
>>
>> @@ -745,7 +762,7 @@ pkt_burst_checksum_forward(struct fwd_stream *fs)
>>   		 * processed in hardware. */
>>   		if (info.is_tunnel == 1) {
>>   			ol_flags |= process_outer_cksums(outer_l3_hdr, &info,
>> -				testpmd_ol_flags);
>> +				testpmd_ol_flags, ol_flags & PKT_TX_TCP_SEG);
>>   		}
>>
>>   		/* step 4: fill the mbuf meta data (flags and header lengths) */ @@ -806,6 +823,10 @@
>
> It was a while since I looked a t it closely, but shouldn't you also update step 4 below:
>
> if (info.is_tunnel == 1) {
>                          if (testpmd_ol_flags & TESTPMD_TX_OFFLOAD_OUTER_IP_CKSUM) {
>                                  m->outer_l2_len = info.outer_l2_len;
>                                  m->outer_l3_len = info.outer_l3_len;
>                                  m->l2_len = info.l2_len;
>                                  m->l3_len = info.l3_len;
>                                  m->l4_len = info.l4_len;
>                          }
>                          else {
>                                  /* if there is a outer UDP cksum
>                                     processed in sw and the inner in hw,
>                                     the outer checksum will be wrong as
>                                     the payload will be modified by the
>                                     hardware */
>                                  m->l2_len = info.outer_l2_len +
>                                          info.outer_l3_len + info.l2_len;
>                                  m->l3_len = info.l3_len;
>                                  m->l4_len = info.l4_len;
>                          }
>
>
> ?
>
> In particular shouldn't it be something like:
> if ((testpmd_ol_flags & TESTPMD_TX_OFFLOAD_OUTER_IP_CKSUM) != 0 ||
>        ((testmpd_ol_flags & TESTPMD_TX_OFFLOAD_PARSE_TUNNEL) != 0 && info.tso_segsz != 0)) {
> ....
> ?

Sorry for late response, because I also take some time to refresh 
memory. And, you are right, I missed this corner case. After applying 
your way above, it works!

The case below settings in testpmd:
$ set fwd csum
$ csum parse_tunnel on 0
$ tso set 800 0
<keep outer-ip checksum offload is sw>

And unfortunately, our previous verification is based on "outer-ip 
checksum offload is hw".

>
> Another thought, might be it is worth to introduce new flag: TESTPMD_TX_OFFLOAD_TSO_TUNNEL,
> and new command in cmdline.c, that would set/clear that flag.
> Instead of trying to make assumptions does
> user wants tso for tunneled packets based on 2 different things:
> - enable/disable tso
> - enable/disable tunneled packets parsing
> ?

Currently, if we do parse_tunnel is based on the command "csum 
parse_tunnel on/off <port>".
If we add a command like "tso_tunnel set <length> <port>", it's a little 
duplicated with "tso set <length> <port>", and there is too much info to 
just set a flag like TESTPMD_TX_OFFLOAD_TSO_TUNNEL;
If we add a command like "csum tunnel_tso on <port>", it also depends on 
"csum parse_tunnel on <port>" so that tunnel packets are parsed.

As far as I can see, the new command will always have semantic 
overlapping with existing commands, because it indeed depends on the two 
different things.

Thanks,
Jianfeng

>
> Konstantin
>