[dpdk-dev] [PATCH 1/3] ethdev: add RSS hash level

[Ajit Khaparde]

On Sat, Dec 7, 2019 at 1:14 AM Andrew Rybchenko <arybchenko at solarflare.com>
wrote:

> On 12/7/19 3:59 AM, Ajit Khaparde wrote:
> > This patch adds ability to configure RSS hash level in hardware.
> > This feature will allow an application to select RSS hash calculation
> > on outer or inner headers for tunneled packets.
> >
> > Signed-off-by: Ajit Khaparde <ajit.khaparde at broadcom.com>
> > ---
> >   lib/librte_ethdev/rte_ethdev.h | 27 +++++++++++++++++++++++++++
> >   1 file changed, 27 insertions(+)
> >
> > diff --git a/lib/librte_ethdev/rte_ethdev.h
> b/lib/librte_ethdev/rte_ethdev.h
> > index 18a9defc2..5189bdbab 100644
> > --- a/lib/librte_ethdev/rte_ethdev.h
> > +++ b/lib/librte_ethdev/rte_ethdev.h
> > @@ -444,11 +444,35 @@ struct rte_vlan_filter_conf {
> >    * The *rss_hf* field of the *rss_conf* structure indicates the
> different
> >    * types of IPv4/IPv6 packets to which the RSS hashing must be applied.
> >    * Supplying an *rss_hf* equal to zero disables the RSS feature.
> > + *
> > + * The *rss_level* field of the *rss_conf* structure indicates the
> > + * Packet encapsulation level RSS hash @p types apply to.
> > + *
> > + * - @p 0 requests the default behavior. Depending on the packet
> > + *   type, it can mean outermost, innermost, anything in between or
> > + *   even no RSS.
> > + *
> > + *   It basically stands for the innermost encapsulation level RSS
> > + *   can be performed on according to PMD and device capabilities.
> > + *
> > + * - @p 1 requests RSS to be performed on the outermost packet
> > + *   encapsulation level.
> > + *
> > + * - @p 2 and subsequent values request RSS to be performed on the
> > + *   specified inner packet encapsulation level, from outermost to
> > + *   innermost (lower to higher values).
> > + *
> > + * Support for values other than @p 0 is dependent on the underlying
> > + * hardware in use.
> > + *
> > + * Requesting a specific RSS level on unrecognized traffic results
> > + * in undefined behavior.
> >    */
> >   struct rte_eth_rss_conf {
> >       uint8_t *rss_key;    /**< If not NULL, 40-byte hash key. */
> >       uint8_t rss_key_len; /**< hash key length in bytes. */
> >       uint64_t rss_hf;     /**< Hash functions to apply - see below. */
> > +     uint32_t rss_level;  /**< RSS hash level */
> >   };
>
> I'm not sure that offload flag is required in this case.
> I think maximum supported rss_level in dev_info will provide

more information and per-queue level does not make sense
> in this case. Even if per-queue group control is required,
> it should be doable via rte_flow API RSS action.
>
This is dev config and not flow specific configuration. Ofcourse while
passing
the rss_config, not all the queues may be specified, but that is not a new
behavior and it is upto the application anyway.

Are we transitioning the device level configuration to rte_flow/flow
based scheme?


>
> Anyway, it looks like it is ABI breakage with all consequences.
> In 64-bit case it is possible to put it before rss_hf to avoid
> ABI breakage, but it will break ABI on 32-bit anyway.
>
Right.
I sent the proposal for review early to get it cleaned up and ready
when the window opens.


>
> >   /*
> > @@ -599,6 +623,8 @@ rte_eth_rss_hf_refine(uint64_t rss_hf)
> >       ETH_RSS_GENEVE | \
> >       ETH_RSS_NVGRE)
> >
> > +#define ETH_RSS_LEVEL_DEFAULT        0
> > +
> >   /*
> >    * Definitions used for redirection table entry size.
> >    * Some RSS RETA sizes may not be supported by some drivers, check the
> > @@ -1103,6 +1129,7 @@ struct rte_eth_conf {
> >   #define DEV_RX_OFFLOAD_SCTP_CKSUM   0x00020000
> >   #define DEV_RX_OFFLOAD_OUTER_UDP_CKSUM  0x00040000
> >   #define DEV_RX_OFFLOAD_RSS_HASH             0x00080000
> > +#define DEV_RX_OFFLOAD_RSS_LEVEL     0x00100000
> >
> >   #define DEV_RX_OFFLOAD_CHECKSUM (DEV_RX_OFFLOAD_IPV4_CKSUM | \
> >                                DEV_RX_OFFLOAD_UDP_CKSUM | \
> >
>
>