[dpdk-dev] [EXT] Re: [PATCH v7 1/3] ethdev: add level support for RSS offload types

[Kiran Kumar Kokkilagadda]

> -----Original Message-----
> From: Ferruh Yigit <ferruh.yigit at intel.com>
> Sent: Tuesday, September 1, 2020 7:08 PM
> To: Kiran Kumar Kokkilagadda <kirankumark at marvell.com>; Thomas Monjalon
> <thomas at monjalon.net>; Andrew Rybchenko <arybchenko at solarflare.com>
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> Subject: [EXT] Re: [dpdk-dev][PATCH v7 1/3] ethdev: add level support for RSS
> offload types
> 
> External Email
> 
> ----------------------------------------------------------------------
> On 9/1/2020 4:27 AM, kirankumark at marvell.com wrote:
> > From: Kiran Kumar K <kirankumark at marvell.com>
> >
> > This patch reserves 2 bits as input selection to select Inner and
> > outer encapsulation level for RSS computation. It is combined with
> > existing
> > ETH_RSS_* to choose Inner or outer layers.
> > This functionality already exists in rte_flow through level parameter
> > in RSS action configuration rte_flow_action_rss.
> >
> > Signed-off-by: Kiran Kumar K <kirankumark at marvell.com>
> > ---
> > V7 Changes:
> > * Re-worked to keep it in sync with rte_flow_action_rss and support
> > upto
> > 3 levels.
> > * Addressed testpmd review comments.
> >
> >   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 70295d7ab..13e49bbd7 100644
> > --- a/lib/librte_ethdev/rte_ethdev.h
> > +++ b/lib/librte_ethdev/rte_ethdev.h
> > @@ -552,6 +552,33 @@ struct rte_eth_rss_conf {
> >   #define RTE_ETH_RSS_L3_PRE64	   (1ULL << 53)
> >   #define RTE_ETH_RSS_L3_PRE96	   (1ULL << 52)
> >
> > +/*
> > + * We use the following macros to combine with the above layers to
> > +choose
> > + * inner and outer layers or both for RSS computation.
> > + * bit 50 and 51 are reserved for this.
> > + */
> > +
> > +/** level 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.
> > + */
> > +#define ETH_RSS_LEVEL_0         (0ULL << 50)
> 
> I can see from history how this is involved, but the 'ETH_RSS_LEVEL_0' naming is
> not really clear what it is, the naming in v6 is more clear.
> 
> What about following one:
> 0 -> LEVEL_PMD_DEFAULT
> 1 -> LEVEL_OUTER
> 2 -> LEVEL_INNER
> 3 -> LEVEL_INNER_OUTER
> 
> This doesn't exactly match to rte_flow one, but closer than v6 one. This ends
> with max level 2. And defines a way to say both inner and outer.

This one looks good to me. If everyone is ok with the proposed changes, I will send V8.

> 
> > +
> > +/** level 1,  requests RSS to be performed on the outermost packet
> > + * encapsulation level.
> > + */
> > +#define ETH_RSS_LEVEL_1         (1ULL << 50)
> > +
> > +/** level 2,  requests RSS to be performed on the
> > + * specified inner packet encapsulation level, from outermost to
> > + * innermost (lower to higher values).
> > + */
> > +#define ETH_RSS_LEVEL_2	        (2ULL << 50)
> 
> I can see you are trying to copy rte_flow usage, but this doesn't really makes
> sense here. Where the value of the level is defined in this case? If not defined
> how the PMD knows which level to use?
> 
> > +#define ETH_RSS_LEVEL_MASK	(3ULL << 50)
> > +
> > +#define ETH_RSS_LEVEL(rss_hf) ((rss_hf & ETH_RSS_LEVEL_MASK) >> 50)
> > +
> >   /**
> >    * For input set change of hash filter, if SRC_ONLY and DST_ONLY of
> >    * the same level are used simultaneously, it is the same case as
> > --
> > 2.25.1
> >