Re: [dpdk-dev] [PATCH v7] ethdev: add IPv4 and L4 checksum RSS offload types

["Zhang, AlvinX" <alvinx.zhang@intel.com>]

> -----Original Message-----
> From: Yigit, Ferruh <ferruh.yigit@intel.com>
> Sent: Tuesday, September 14, 2021 10:01 PM
> To: Zhang, AlvinX <alvinx.zhang@intel.com>; Zhang, Qi Z
> <qi.z.zhang@intel.com>; Guo, Junfeng <junfeng.guo@intel.com>
> Cc: dev@dpdk.org; Ajit Khaparde <ajit.khaparde@broadcom.com>; Singh,
> Aman Deep <aman.deep.singh@intel.com>
> Subject: Re: [dpdk-dev] [PATCH v7] ethdev: add IPv4 and L4 checksum RSS
> offload types
> 
> On 8/31/2021 10:52 AM, Alvin Zhang wrote:
> > This patch defines new RSS offload types for IPv4 and
> > L4(TCP/UDP/SCTP) checksum, which are required when users want to
> > distribute packets based on the IPv4 or L4 checksum field.
> >
> > For example "flow create 0 ingress pattern eth / ipv4 / end actions
> > rss types ipv4-chksum end queues end / end", this flow causes all
> > matching packets to be distributed to queues on basis of IPv4
> > checksum.
> >
> > Signed-off-by: Alvin Zhang <alvinx.zhang@intel.com>
> > Acked-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
> > Acked-by: Aman Deep Singh <aman.deep.singh@intel.com>
> > ---
> >
> > v6: rebase to eeedef70, update some note
> > v7: fix code style issues
> > ---
> >  app/test-pmd/cmdline.c                 |  4 +++-
> >  app/test-pmd/config.c                  |  2 ++
> >  doc/guides/rel_notes/release_21_11.rst |  5 +++++
> >  lib/ethdev/rte_ethdev.h                | 24
> ++++++++++++++++++++++++
> >  4 files changed, 34 insertions(+), 1 deletion(-)
> >
> > diff --git a/app/test-pmd/cmdline.c b/app/test-pmd/cmdline.c index
> > 82253bc..656a311 100644
> > --- a/app/test-pmd/cmdline.c
> > +++ b/app/test-pmd/cmdline.c
> > @@ -2252,6 +2252,8 @@ struct cmd_config_rss {
> >  		rss_conf.rss_hf = ETH_RSS_ECPRI;
> >  	else if (!strcmp(res->value, "mpls"))
> >  		rss_conf.rss_hf = ETH_RSS_MPLS;
> > +	else if (!strcmp(res->value, "ipv4-chksum"))
> > +		rss_conf.rss_hf = ETH_RSS_IPV4_CHKSUM;
> >  	else if (!strcmp(res->value, "none"))
> >  		rss_conf.rss_hf = 0;
> >  	else if (!strcmp(res->value, "level-default")) { @@ -2323,7 +2325,7
> > @@ struct cmd_config_rss {
> >  	.help_str = "port config all rss "
> >  		"all|default|eth|vlan|ip|tcp|udp|sctp|ether|port|vxlan|geneve|"
> >
> 	"nvgre|vxlan-gpe|l2tpv3|esp|ah|pfcp|ecpri|mpls|none|level-default|"
> > -		"level-outer|level-inner|<flowtype_id>",
> > +		"level-outer|level-inner|ipv4-chksum|<flowtype_id>",
> >  	.tokens = {
> >  		(void *)&cmd_config_rss_port,
> >  		(void *)&cmd_config_rss_keyword,
> > diff --git a/app/test-pmd/config.c b/app/test-pmd/config.c index
> > 31d8ba1..ece78f2 100644
> > --- a/app/test-pmd/config.c
> > +++ b/app/test-pmd/config.c
> > @@ -140,6 +140,8 @@
> >  	{ "gtpu", ETH_RSS_GTPU },
> >  	{ "ecpri", ETH_RSS_ECPRI },
> >  	{ "mpls", ETH_RSS_MPLS },
> > +	{ "ipv4-chksum", ETH_RSS_IPV4_CHKSUM },
> > +	{ "l4-chksum", ETH_RSS_L4_CHKSUM },>  	{ NULL, 0 },
> >  };
> >
> > diff --git a/doc/guides/rel_notes/release_21_11.rst
> > b/doc/guides/rel_notes/release_21_11.rst
> > index d707a55..fa29b13 100644
> > --- a/doc/guides/rel_notes/release_21_11.rst
> > +++ b/doc/guides/rel_notes/release_21_11.rst
> > @@ -55,6 +55,11 @@ New Features
> >       Also, make sure to start the actual text at the margin.
> >       =======================================================
> >
> > +* **Add new RSS offload types for IPv4/L4 checksum in RSS flow.**
> > +
> > +  Add macros ETH_RSS_IPV4_CHKSUM and ETH_RSS_L4_CHKSUM, now IPv4
> and
> > + TCP/UDP/SCTP header checksum field can be used as input set for RSS.
> > +
> >
> >  Removed Items
> >  -------------
> > diff --git a/lib/ethdev/rte_ethdev.h b/lib/ethdev/rte_ethdev.h index
> > d2b27c3..e6734df 100644
> > --- a/lib/ethdev/rte_ethdev.h
> > +++ b/lib/ethdev/rte_ethdev.h
> > @@ -537,6 +537,30 @@ struct rte_eth_rss_conf {
> >  #define ETH_RSS_PPPOE		   (1ULL << 31)
> >  #define ETH_RSS_ECPRI		   (1ULL << 32)
> >  #define ETH_RSS_MPLS		   (1ULL << 33)
> > +#define ETH_RSS_IPV4_CHKSUM	   (1ULL << 34)
> > +
> > +/**
> > + * The ETH_RSS_L4_CHKSUM generally refers to a type of checksum field
> > +for
> 
> what does 'generally' means here? Is there a case it refers to something else?
> 
> > + * any L4 header, such as TCP, UDP and SCTP. It is similar to
> > + ETH_RSS_PORT,
> > + * it does not specify the type of L4 header.
> > + * We use this macro to replace below macro for constricting the use
> > + of RSS
> > + * offload bits:
> > + * ETH_RSS_IPV4_TCP_CHKSUM
> > + * ETH_RSS_IPV4_UDP_CHKSUM
> > + * ETH_RSS_IPV4_SCTP_CHKSUM
> > + * ETH_RSS_IPV6_TCP_CHKSUM
> > + * ETH_RSS_IPV6_UDP_CHKSUM
> > + * ETH_RSS_IPV6_SCTP_CHKSUM
> 
> As I get you are listing them here to say the 'ETH_RSS_L4_CHKSUM' replaces
> possible usage of above list, but my concern is it may confuse people as those
> macros exists (or did exist in the past), so what do you think to remove them?
> 
> 
> And just to confirm, we can't use this flag, 'ETH_RSS_L4_CHKSUM' anymore with
> 'rte_eth_rss_conf.rss_hf', right? Since it will be missing some context for it.
> Which means some old APIs (and configuration) won't support this new offload,
> but only rte_flow will support it.
> If above is correct should it be highlighted in above comment?
> 
> > + *
> > + * Then how to use this macro? We can use it in RSS flow where the
> > + pattern
> 
> Can we convert this question to a description just to be a little more formal?
> 
> > + * type will specify the L4 header type, for example "flow create 0
> > +ingress \
> > + * pattern eth / ipv4 / tcp / end actions rss types l4-chksum  end
> > +queues end \
> > + * / end"
> > + *
> > + * For the case that checksum is not used in a UDP header, it takes
> > +the
> > + * reserved value 0 as input for the hash function.
> > + */
> > +#define ETH_RSS_L4_CHKSUM	   (1ULL << 35)
> >
> >  /*
> >   * We use the following macros to combine with above ETH_RSS_* for
> >

I'll refine the notes.
Thanks,
Alvin