Re: [dpdk-dev] [PATCH v8 2/3] ethdev: extend RSS offload types

["Iremonger, Bernard" <bernard.iremonger@intel.com>]

Hi Simei,

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Andrew Rybchenko
> Sent: Tuesday, October 1, 2019 3:49 PM
> To: Su, Simei <simei.su@intel.com>; Zhang, Qi Z <qi.z.zhang@intel.com>; Ye,
> Xiaolong <xiaolong.ye@intel.com>; Yigit, Ferruh <ferruh.yigit@intel.com>
> Cc: dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v8 2/3] ethdev: extend RSS offload types
> 
> On 10/1/19 5:36 PM, Simei Su wrote:
> > This patch reserves several bits as input set selection from the high
> > end of the 64 bits. It is combined with exisiting ETH_RSS_* to
> > represent RSS types.
> >
> > Signed-off-by: Simei Su <simei.su@intel.com>
> > Reviewed-by: Qi Zhang <qi.z.zhang@intel.com>
> > Acked-by: Ori Kam <orika@mellanox.com>
> > ---
> >   lib/librte_ethdev/rte_ethdev.c | 22 ++++++++++++++++++++++
> >   lib/librte_ethdev/rte_ethdev.h | 14 ++++++++++++++
> >   2 files changed, 36 insertions(+)
> >
> > diff --git a/lib/librte_ethdev/rte_ethdev.c
> > b/lib/librte_ethdev/rte_ethdev.c index af82360..5e5a974 100644
> > --- a/lib/librte_ethdev/rte_ethdev.c
> > +++ b/lib/librte_ethdev/rte_ethdev.c
> > @@ -1269,6 +1269,17 @@ struct rte_eth_dev *
> >   		goto rollback;
> >   	}
> >
> > +	/* simplified the SRC/DST_ONLY RSS offload modificaiton */
> > +	if (dev_conf->rx_adv_conf.rss_conf.rss_hf &
> ETH_RSS_L3_SRC_ONLY &&
> > +		dev_conf->rx_adv_conf.rss_conf.rss_hf &
> ETH_RSS_L3_DST_ONLY)
> 
> I'm afraid some compiler versions could bark about missing parenthesis here.
> Consider to use something like:
>   (rss_conf->rss_hf & (ETH_RSS_L3_SRC_ONLY | ETH_RSS_L3_DST_ONLY) ==
>    (ETH_RSS_L3_SRC_ONLY | ETH_RSS_L3_DST_ONLY)) May be parenthesis
> around & is not required.
> 
> > +			dev->data->dev_conf.rx_adv_conf.rss_conf.rss_hf
> &=
> > +				~(ETH_RSS_L3_SRC_ONLY |
> ETH_RSS_L3_DST_ONLY);
> > +
> > +	if (dev_conf->rx_adv_conf.rss_conf.rss_hf &
> ETH_RSS_L4_SRC_ONLY &&
> > +		dev_conf->rx_adv_conf.rss_conf.rss_hf &
> ETH_RSS_L4_DST_ONLY)
> > +			dev->data->dev_conf.rx_adv_conf.rss_conf.rss_hf
> &=
> > +				~(ETH_RSS_L4_SRC_ONLY |
> ETH_RSS_L4_DST_ONLY);
> > +
> 
> I think it is wrong to duplicate the logic twice (here and below).
> Helper static function should be used to avoid it.
> 
> >   	/* Check that device supports requested rss hash functions. */
> >   	if ((dev_info.flow_type_rss_offloads |
> >   	     dev_conf->rx_adv_conf.rss_conf.rss_hf) != @@ -3112,6 +3123,17
> > @@ struct rte_eth_dev *
> >   	if (ret != 0)
> >   		return ret;
> >
> > +	/* simplified the SRC/DST_ONLY RSS offload modificaiton */
> > +	if (rss_conf->rss_hf & ETH_RSS_L3_SRC_ONLY &&
> > +		rss_conf->rss_hf & ETH_RSS_L3_DST_ONLY)
> > +			rss_conf->rss_hf &=
> > +				~(ETH_RSS_L3_SRC_ONLY |
> ETH_RSS_L3_DST_ONLY);
> > +
> > +	if (rss_conf->rss_hf & ETH_RSS_L4_SRC_ONLY &&
> > +		rss_conf->rss_hf & ETH_RSS_L4_DST_ONLY)
> > +			rss_conf->rss_hf &=
> > +				~(ETH_RSS_L4_SRC_ONLY |
> ETH_RSS_L4_DST_ONLY);
> > +
> >   	dev = &rte_eth_devices[port_id];
> >   	if ((dev_info.flow_type_rss_offloads | rss_conf->rss_hf) !=
> >   	    dev_info.flow_type_rss_offloads) { diff --git
> > a/lib/librte_ethdev/rte_ethdev.h b/lib/librte_ethdev/rte_ethdev.h
> > index 7722f70..6d61b84 100644
> > --- a/lib/librte_ethdev/rte_ethdev.h
> > +++ b/lib/librte_ethdev/rte_ethdev.h
> > @@ -505,6 +505,20 @@ struct rte_eth_rss_conf {
> >   #define ETH_RSS_GENEVE             (1ULL << 20)
> >   #define ETH_RSS_NVGRE              (1ULL << 21)
> >
> > +/*
> > + * We use the following macros to combine with above ETH_RSS_* for
> > + * more specific input set selection. These bits are defined starting
> > + * from the high end of the 64 bits.
> > + * Note: If we use above ETH_RSS_* without SRC/DST_ONLY, it
> > +represents
> > + * both SRC and DST are taken into account. If SRC_ONLY and DST_ONLY
> > +of
> > + * the same level be used simultaneously, it is the same case as none
> > +of
> > + * them are added.
> > + */
> > +#define ETH_RSS_L3_SRC_ONLY        (1ULL << 63)
> > +#define ETH_RSS_L3_DST_ONLY        (1ULL << 62)
> > +#define ETH_RSS_L4_SRC_ONLY        (1ULL << 61)
> > +#define ETH_RSS_L4_DST_ONLY        (1ULL << 60)
> > +
> >   #define ETH_RSS_IP ( \
> >   	ETH_RSS_IPV4 | \
> >   	ETH_RSS_FRAG_IPV4 | \

This patch fails to apply to the latest master branch, a rebase may be needed.

Regards,

Bernard