Re: [dpdk-dev] [PATCH v2 1/4] ethdev: add Rx offload outer UDP checksum definition

[Jerin Jacob <jerin.jacob@caviumnetworks.com>]

-----Original Message-----
> Date: Wed, 3 Oct 2018 13:27:13 +0530
> From: Jerin Jacob <jerin.jacob@caviumnetworks.com>
> To: Andrew Rybchenko <arybchenko@solarflare.com>
> CC: Wenzhuo Lu <wenzhuo.lu@intel.com>, Jingjing Wu <jingjing.wu@intel.com>,
>  Bernard Iremonger <bernard.iremonger@intel.com>, John McNamara
>  <john.mcnamara@intel.com>, Marko Kovacevic <marko.kovacevic@intel.com>,
>  Thomas Monjalon <thomas@monjalon.net>, Ferruh Yigit
>  <ferruh.yigit@intel.com>, Olivier Matz <olivier.matz@6wind.com>,
>  dev@dpdk.org, shahafs@mellanox.com, "Ananyev, Konstantin"
>  <konstantin.ananyev@intel.com>
> Subject: Re: [dpdk-dev] [PATCH v2 1/4] ethdev: add Rx offload outer UDP
>  checksum definition
> User-Agent: Mutt/1.10.1 (2018-07-13)
> 
> External Email
> 
> -----Original Message-----
> > Date: Wed, 3 Oct 2018 10:34:52 +0300
> > From: Andrew Rybchenko <arybchenko@solarflare.com>
> > To: Jerin Jacob <jerin.jacob@caviumnetworks.com>, Wenzhuo Lu
> >  <wenzhuo.lu@intel.com>, Jingjing Wu <jingjing.wu@intel.com>, Bernard
> >  Iremonger <bernard.iremonger@intel.com>, John McNamara
> >  <john.mcnamara@intel.com>, Marko Kovacevic <marko.kovacevic@intel.com>,
> >  Thomas Monjalon <thomas@monjalon.net>, Ferruh Yigit
> >  <ferruh.yigit@intel.com>, Olivier Matz <olivier.matz@6wind.com>
> > CC: dev@dpdk.org, shahafs@mellanox.com, "Ananyev, Konstantin"
> >  <konstantin.ananyev@intel.com>
> > Subject: Re: [dpdk-dev] [PATCH v2 1/4] ethdev: add Rx offload outer UDP
> >  checksum definition
> > User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101
> >  Thunderbird/60.0
> >
> >
> > On 10/2/18 10:24 PM, Jerin Jacob wrote:
> >
> > Introduced DEV_RX_OFFLOAD_OUTER_UDP_CKSUM Rx offload flag and
> > PKT_RX_EL4_CKSUM_BAD mbuf ol_flags to detect outer UDP checksum
> > failure.
> >
> > - To use hardware Rx outer UDP checksum offload, the user needs to
> > configure DEV_RX_OFFLOAD_OUTER_UDP_CKSUM offload flags in slowpath.
> >
> > - Driver updates the PKT_RX_EL4_CKSUM_BAD mbuf ol_flag on checksum failure
> > similar to the outer L3 PKT_RX_EIP_CKSUM_BAD flag.
> >
> > Signed-off-by: Jerin Jacob <jerin.jacob@caviumnetworks.com><mailto:jerin.jacob@caviumnetworks.com>
> >
> > 1. I'm not sure that it is OK that mbuf and ethdev changes go in one patch.
> >    It seems typically mbuf changes go separately and mbuf changes should
> >    be applied to main dpdk repo.
> 
> 
> I don't have strong opinion on this. If there are no other objection, I
> will split the patch further as mbuf and ethdev as you pointed out.
> 
> >
> > 2. I'd like to see thought why single bit is used for outer L2 checksum when
> >    2 bits (UNKNOWN, BAD, GOOD, NONE) are used for PKT_RX_L4_CKSUM.
> >    May be it is OK, but it would be useful to state explicitly why it is decided
> >    to go this way.
> 
> I am following the scheme similar to OUTER IP checksum where we have only
> one bit filed(PKT_RX_EIP_CKSUM_BAD). I will mention in the git commit.
> 
> 
> >
> > 3. PKT_RX_L4_CKSUM_MASK description says nothing if it is inner or outer.
> >    May be it is not directly related to changeset, but I think it would be really
> >    useful to clarify it.
> 
> I will update the comment.

Hi Andrew,

I looked at the other definitions in mbuf.h, according the documentation,
If nothing is mentioned it is treated as inner if the packet is
tunneled else it is outer most. So I would like avoid confusion by
adding "inner" in the exiting PKT_RX_L4_CKSUM_MASK comment.
Technically it is not correct to say "inner" if the packet is not
tunneled. So I am untouching the exiting comment.


> 
> >
> >
> > Plus one nit below.
> >
> >
> >
> > ---
> >
> > v2:
> > - Removed DEV_RX_OFFLOAD_OUTER_TCP_CKSUM and DEV_RX_OFFLOAD_OUTER_SCTP_CKSUM
> > as there is no realworld use case for it.
> > See: http://patches.dpdk.org/patch/44692/
> >
> > This patch series is depended on http://patches.dpdk.org/patch/45840/
> >
> > --
> > app/test-pmd/config.c          | 9 +++++++++
> > doc/guides/nics/features.rst   | 3 +++
> > lib/librte_ethdev/rte_ethdev.c | 1 +
> > lib/librte_ethdev/rte_ethdev.h | 1 +
> > lib/librte_mbuf/rte_mbuf.c     | 2 ++
> > lib/librte_mbuf/rte_mbuf.h     | 3 +++
> > 6 files changed, 19 insertions(+)
> >
> > diff --git a/app/test-pmd/config.c b/app/test-pmd/config.c
> > index 1adc9b94b..d53c527e5 100644
> > --- a/app/test-pmd/config.c
> > +++ b/app/test-pmd/config.c
> > @@ -594,6 +594,15 @@ port_offload_cap_display(portid_t port_id)
> >                        printf("off\n");
> >        }
> >
> > +       if (dev_info.rx_offload_capa & DEV_RX_OFFLOAD_OUTER_UDP_CKSUM) {
> > +               printf("RX Outer UDP checksum:               ");
> > +               if (ports[port_id].dev_conf.rxmode.offloads &
> > +                   DEV_RX_OFFLOAD_OUTER_UDP_CKSUM)
> > +                       printf("on\n");
> > +               else
> > +                       printf("off\n");
> > +       }
> > +
> >        if (dev_info.rx_offload_capa & DEV_RX_OFFLOAD_TCP_LRO) {
> >                printf("Large receive offload:         ");
> >                if (ports[port_id].dev_conf.rxmode.offloads &
> > diff --git a/doc/guides/nics/features.rst b/doc/guides/nics/features.rst
> > index d42489b6d..2c2959e0b 100644
> > --- a/doc/guides/nics/features.rst
> > +++ b/doc/guides/nics/features.rst
> > @@ -639,6 +639,9 @@ Inner L4 checksum
> >
> > Supports inner packet L4 checksum.
> >
> > +* **[uses]     rte_eth_rxconf,rte_eth_rxmode**: ``offloads:DEV_RX_OFFLOAD_OUTER_UDP_CKSUM``.
> > +* **[provides] mbuf**: ``mbuf.ol_flags:PKT_RX_EL4_CKSUM_BAD``.
> > +* **[provides] rte_eth_dev_info**: ``rx_offload_capa,rx_queue_offload_capa:DEV_RX_OFFLOAD_OUTER_UDP_CKSUM``,
> >
> >
> > One more empty line should be added here to have two empty lines between features.
> 
> OK.
> 
> Thanks for the review.
> 
> >
> > Andrew.