Re: [PATCH v2 08/15] ethdev: add hash function to RSS flow API action

[Adrien Mazarguil <adrien.mazarguil@6wind.com>]

On Fri, Apr 06, 2018 at 06:41:35PM +0300, Andrew Rybchenko wrote:
> On 04/06/2018 04:25 PM, Adrien Mazarguil wrote:
> > By definition, RSS involves some kind of hash algorithm, usually Toeplitz.
> > 
> > Until now it could not be modified on a flow rule basis and PMDs had to
> > always assume RTE_ETH_HASH_FUNCTION_DEFAULT, which remains the default
> > behavior when unspecified (0).
> > 
> > This breaks ABI compatibility for the following public functions:
> > 
> > - rte_flow_copy()
> > - rte_flow_create()
> > - rte_flow_query()
> > - rte_flow_validate()
> > 
> > Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
> > Cc: Ferruh Yigit <ferruh.yigit@intel.com>
> > Cc: Thomas Monjalon <thomas@monjalon.net>
> > Cc: Wenzhuo Lu <wenzhuo.lu@intel.com>
> > Cc: Jingjing Wu <jingjing.wu@intel.com>
> > Cc: Beilei Xing <beilei.xing@intel.com>
> > Cc: Qi Zhang <qi.z.zhang@intel.com>
> > Cc: Konstantin Ananyev <konstantin.ananyev@intel.com>
> > Cc: Nelio Laranjeiro <nelio.laranjeiro@6wind.com>
> > Cc: Yongseok Koh <yskoh@mellanox.com>
> > Cc: Andrew Rybchenko <arybchenko@solarflare.com>
> > Cc: Pascal Mazon <pascal.mazon@6wind.com>
> > ---
> >   app/test-pmd/cmdline_flow.c                 | 72 ++++++++++++++++++++++++
> >   app/test-pmd/config.c                       |  1 +
> >   doc/guides/prog_guide/rte_flow.rst          |  2 +
> >   doc/guides/testpmd_app_ug/testpmd_funcs.rst |  3 +
> >   drivers/net/e1000/igb_flow.c                |  4 ++
> >   drivers/net/e1000/igb_rxtx.c                |  4 +-
> >   drivers/net/i40e/i40e_ethdev.c              |  4 +-
> >   drivers/net/i40e/i40e_flow.c                |  4 ++
> >   drivers/net/ixgbe/ixgbe_flow.c              |  4 ++
> >   drivers/net/ixgbe/ixgbe_rxtx.c              |  4 +-
> >   drivers/net/mlx4/mlx4_flow.c                |  7 +++
> >   drivers/net/mlx5/mlx5_flow.c                | 13 +++++
> >   drivers/net/sfc/sfc_flow.c                  |  3 +
> >   drivers/net/tap/tap_flow.c                  |  6 ++
> >   lib/librte_ether/rte_flow.c                 |  1 +
> >   lib/librte_ether/rte_flow.h                 |  2 +
> >   16 files changed, 131 insertions(+), 3 deletions(-)
> 
> <...>
> 
> > diff --git a/drivers/net/sfc/sfc_flow.c b/drivers/net/sfc/sfc_flow.c
> > index 1a2c0299c..dbe4c2baa 100644
> > --- a/drivers/net/sfc/sfc_flow.c
> > +++ b/drivers/net/sfc/sfc_flow.c
> > @@ -1261,6 +1261,9 @@ sfc_flow_parse_rss(struct sfc_adapter *sa,
> >   			rxq_hw_index_max = rxq->hw_index;
> >   	}
> > +	if (rss->func)
> 
> May be it is better to compare with RTE_ETH_HASH_FUNCTION_DEFAULT
> explicitly? I think it is more readable. If so, it is applicable to all
> similar checks
> in the patch.

Good suggestion, although RTE_ETH_HASH_FUNCTION_DEFAULT can't be anything
other than 0 for various reasons, I'll clarify (most of) the code in my next
update.

> In the case of sfc, please, allow RTE_ETH_HASH_FUNCTION_TOEPLITZ as well.
> I'd suggest:
> switch (rss->func) {
> case RTE_ETH_HASH_FUNCTION_DEFAULT:
> case RTE_ETH_HASH_FUNCTION_TOEPLITZ:
>       break;
> default:
>       return -EINVAL;
> }

I'll add it, thanks.

-- 
Adrien Mazarguil
6WIND