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

["Ananyev, Konstantin" <konstantin.ananyev@intel.com>]

Hi Jianfeng,

> 
> Hi Konstantin,
> 
> 
> On 9/21/2016 11:47 PM, Ananyev, Konstantin wrote:
> > Hi Jianfeng,
> >
> >> 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>
> > Great :)
> >
> >> 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.
> > But I thought in some cases user might want to enable tunnel parsing, but do tso for non-tunneled packets only.
> > I.E.
> >   - enable tunnel parsing
> > - for non-tunneled packets do tso
> > - for tunneled packets don't do tso
> > My understanding that with current set commands/flags this is not possible, correct?
> > Konstantin
> 
> Yes, correct, above case is not supported now. A twin case would be:
> - for non-tunneled packets, don't do tso
> - for tunneled packets, do tso

Yep, you right.

> 
> Considering above two cases, so how about adding a command like; $ tunnel_tso set 800 0 which needs "csum parse_tunnel on 0" has
> been set before it.
> 
> And original "tso set 800 0" will only control tso of non-tunneled packets.

Looks good for me.
Konstantin