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: http://dpdk.org/dev/patchwork/patch/17184/. 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 > > > > 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?
