[dpdk-dev] [PATCH v12 0/6] add Tx preparation

[Alejandro Lucero]

For NFP, we do not have TSO support yet, although it is coming and
hopefully it will be within next release.

Regarding this email thread, it is "it is OK, we do not need any checksum
preparation for TSO"

On Wed, Dec 7, 2016 at 10:03 AM, Ananyev, Konstantin <
konstantin.ananyev at intel.com> wrote:

>
> Hi Ferruh,
>
> >
> > On 12/6/2016 6:25 PM, Yong Wang wrote:
> > >> -----Original Message-----
> > >> From: Ananyev, Konstantin [mailto:konstantin.ananyev at intel.com]
> > >> Sent: Sunday, December 4, 2016 4:11 AM
> > >> To: Yong Wang <yongwang at vmware.com>; Thomas Monjalon
> > >> <thomas.monjalon at 6wind.com>
> > >> Cc: Harish Patil <harish.patil at qlogic.com>; dev at dpdk.org; Rahul
> Lakkireddy
> > >> <rahul.lakkireddy at chelsio.com>; Stephen Hurd
> > >> <stephen.hurd at broadcom.com>; Jan Medala <jan at semihalf.com>; Jakub
> > >> Palider <jpa at semihalf.com>; John Daley <johndale at cisco.com>; Adrien
> > >> Mazarguil <adrien.mazarguil at 6wind.com>; Alejandro Lucero
> > >> <alejandro.lucero at netronome.com>; Rasesh Mody
> > >> <rasesh.mody at qlogic.com>; Jacob, Jerin <Jerin.Jacob at cavium.com>;
> > >> Yuanhan Liu <yuanhan.liu at linux.intel.com>; Kulasek, TomaszX
> > >> <tomaszx.kulasek at intel.com>; olivier.matz at 6wind.com
> > >> Subject: RE: [dpdk-dev] [PATCH v12 0/6] add Tx preparation
> > >>
> > >> Hi
> > >>
> > >>
> > >>
> > >>>>
> > >>
> > >>>> 2016-11-30 17:42, Ananyev, Konstantin:
> > >>
> > >>>>>>> Please, we need a comment for each driver saying
> > >>
> > >>>>>>> "it is OK, we do not need any checksum preparation for TSO"
> > >>
> > >>>>>>> or
> > >>
> > >>>>>>> "yes we have to implement tx_prepare or TSO will not work in this
> > >>
> > >>>> mode"
> > >>
> > >>>>>>>
> > >>
> > >>>>>>
> > >>
> > >>>>>> qede PMD doesn’t currently support TSO yet, it only supports Tx
> > >>
> > >>>> TCP/UDP/IP
> > >>
> > >>>>>> csum offloads.
> > >>
> > >>>>>> So Tx preparation isn’t applicable. So as of now -
> > >>
> > >>>>>> "it is OK, we do not need any checksum preparation for TSO"
> > >>
> > >>>>>
> > >>
> > >>>>> Thanks for the answer.
> > >>
> > >>>>> Though please note that it not only for TSO.
> > >>
> > >>>>
> > >>
> > >>>> Oh yes, sorry, my wording was incorrect.
> > >>
> > >>>> We need to know if any checksum preparation is needed prior
> > >>
> > >>>> offloading its final computation to the hardware or driver.
> > >>
> > >>>> So the question applies to TSO and simple checksum offload.
> > >>
> > >>>>
> > >>
> > >>>> We are still waiting answers for
> > >>
> > >>>>  bnxt, cxgbe, ena, nfp, thunderx, virtio and vmxnet3.
> > >>
> > >>>
> > >>
> > >>> The case for a virtual device is a little bit more complicated as
> packets
> > >> offloaded from a virtual device can eventually be delivered to
> > >>
> > >>> another virtual NIC or different physical NICs that have different
> offload
> > >> requirements.  In ESX, the hypervisor will enforce that the packets
> > >>
> > >>> offloaded will be something that the hardware expects.  The contract
> for
> > >> vmxnet3 is that the guest needs to fill in pseudo header checksum
> > >>
> > >>> for both l4 checksum only and TSO + l4 checksum offload cases.
> > >>
> > >>
> > >>
> > >> Ok, so at first glance that looks to me very similar to Intel HW
> requirements.
> > >>
> > >> Could you confirm would rte_net_intel_cksum_prepare()
> > >>
> > >> also work for vmxnet3 or some extra modifications are required?
> > >>
> > >> You can look at it here: https://urldefense.proofpoint.
> com/v2/url?u=http-
> > >> 3A__dpdk.org_dev_patchwork_patch_17184_&d=DgIGaQ&c=uilaK90D4TOV
> > >> oH58JNXRgQ&r=v4BBYIqiDq552fkYnKKFBFyqvMXOR3UXSdFO2plFD1s&m=NS
> > >> 4zOl2je_tyGhnOJMSnu37HmJxOZf-1KLYcVsu8iYY&s=dL-NOC-
> > >> 18HclXUURQzuyW5Udw4NY13pKMndYvfgCfbA&e= .
> > >>
> > >> Note that for Intel HW the rules for pseudo-header csum calculation
> > >>
> > >> differ for TSO and non-TSO case.
> > >>
> > >> For TSO length inside pseudo-header are set to 0, while for non-tso
> case
> > >>
> > >> It should be set to L3 payload length.
> > >>
> > >> Is it the same for vmxnet3 or no?
> > >>
> > >> Thanks
> > >>
> > >> Konstantin
> > >>
> > >
> > > Yes and this is the same for vmxnet3.
> > >
> >
> > This means vmxnet3 PMD also should be updated, right?
>
> Yes, that's right.
>
> >Should that update
> > be part of tx_prep patchset? Or separate patch?
>
> Another question I suppose is who will do the actual patch for vmxnet3.
> Yong, are you ok to do the patch for vmxnet3, or prefer us to do that?
> Please note, that in both cases will need your help in testing/reviewing
> it.
> Konstantin
>
> >
> > >>>
> > >>
> > >>>>> This is for any TX offload for which the upper layer SW would have
> > >>
> > >>>>> to modify the contents of the packet.
> > >>
> > >>>>> Though as I can see for qede neither PKT_TX_IP_CKSUM or
> > >>
> > >>>> PKT_TX_TCP_CKSUM
> > >>
> > >>>>> exhibits any extra requirements for the user.
> > >>
> > >>>>> Is that correct?
> > >>
> > >>
> > >
>
>