Re: [dpdk-dev] [DPDK] lib/librte_ether: add comments RSS flags

[Thomas Monjalon <thomas@monjalon.net>]

07/01/2018 07:32, Shahaf Shuler:
> Saturday, January 6, 2018 12:22 PM, Andrew Rybchenko:
> 
> [..]
> 
> > >   #define ETH_RSS_PORT               (1ULL << RTE_ETH_FLOW_PORT)
> > > +/** Enable RSS offload on VXLAN packets */
> > >   #define ETH_RSS_VXLAN              (1ULL << RTE_ETH_FLOW_VXLAN)
> > > +/** Enable RSS offload on GENEVE packets */
> > >   #define ETH_RSS_GENEVE             (1ULL << RTE_ETH_FLOW_GENEVE)
> > > +/** Enable RSS offload on NVGRE packets */
> > >   #define ETH_RSS_NVGRE              (1ULL << RTE_ETH_FLOW_NVGRE)
> > >
> > >   #define ETH_RSS_IP ( \
> > 
> > These comments just decode the define name and not that useful. What
> > would be really useful here is specification of which fields of the packet
> > headers are used to calculate hash especially in the case of tunnels.
> 
> +1.
> 
> Also maybe some more clarifications, for example:
> 1. What is the expected behavior when, for example, setting the ETH_RSS_IPV6_EX and regular IPv6 packet arrives? is RSS apply on it? 
> 2. What is the expected behavior from the PMD when not supporting one of the RSS types? 
>      For example most of the DPDK examples uses ETH_RSS_IP [1], however very few devices actually supports each and every RSS type.
>      Assuming such configuration returns with no error, what should application expect when unsupported packet type arrives. 
> 
> #define ETH_RSS_IP ( \                
>         ETH_RSS_IPV4 | \              
>         ETH_RSS_FRAG_IPV4 | \         
>         ETH_RSS_NONFRAG_IPV4_OTHER | \
>         ETH_RSS_IPV6 | \              
>         ETH_RSS_FRAG_IPV6 | \         
>         ETH_RSS_NONFRAG_IPV6_OTHER | \
>         ETH_RSS_IPV6_EX)              

+1
We really need a detailed documentation of the exact behaviour.

It must be at least as detailed as lib/librte_mbuf/rte_mbuf_ptype.h.
Thanks