Re: [dpdk-dev] [PATCH v4] ethdev: add IPv4 and L4 checksum RSS offload types

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

> -----Original Message-----
> From: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> Sent: Tuesday, July 13, 2021 6:24 PM
> To: Zhang, AlvinX <alvinx.zhang@intel.com>; Zhang, Qi Z
> <qi.z.zhang@intel.com>; ajit.khaparde@broadcom.com
> Cc: dev@dpdk.org; Singh, Aman Deep <aman.deep.singh@intel.com>
> Subject: Re: [PATCH v4] ethdev: add IPv4 and L4 checksum RSS offload types
> 
> On 7/13/21 12:38 PM, Zhang, AlvinX wrote:
> >> -----Original Message-----
> >> From: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> >> Sent: Tuesday, July 13, 2021 3:55 PM
> >> To: Zhang, AlvinX <alvinx.zhang@intel.com>; Zhang, Qi Z
> >> <qi.z.zhang@intel.com>; ajit.khaparde@broadcom.com
> >> Cc: dev@dpdk.org; Singh, Aman Deep <aman.deep.singh@intel.com>
> >> Subject: Re: [PATCH v4] ethdev: add IPv4 and L4 checksum RSS offload
> >> types
> >>
> >> On 7/13/21 4:13 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>
> >>> Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> >>
> >> I've failed to find mail where I've added the tag. I've replied with
> >> "LGTM" for v2 which has IPv4 checksum only and many comments on L4
> checksum added in v3.
> >> So, I think it is incorrect to inherit "LGTM" as Reviewed-by.
> >>
> >
> > I'll correct it at next version.
> >
> >>> Acked-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
> >>> Acked-by: Aman Deep Singh <aman.deep.singh@intel.com>
> >>> ---
> >>>
> >>> v3: Add L4 checksum RSS offload type
> >>> v4: Add doc and help string, update commit log
> >>> ---
> >>>  app/test-pmd/cmdline.c  | 12 +++++++++---
> >>>  app/test-pmd/config.c   |  2 ++
> >>>  lib/ethdev/rte_ethdev.h |  2 ++
> >>>  3 files changed, 13 insertions(+), 3 deletions(-)
> >>>
> >>> diff --git a/app/test-pmd/cmdline.c b/app/test-pmd/cmdline.c index
> >>> 0268b18..93543d8 100644
> >>> --- a/app/test-pmd/cmdline.c
> >>> +++ b/app/test-pmd/cmdline.c
> >>> @@ -2254,6 +2254,10 @@ 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, "l4-chksum"))
> >>> +		rss_conf.rss_hf = ETH_RSS_L4_CHKSUM;
> >>>  	else if (!strcmp(res->value, "none"))
> >>>  		rss_conf.rss_hf = 0;
> >>>  	else if (!strcmp(res->value, "level-default")) { @@ -2325,7
> >>> +2329,7 @@ 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|l4-chksum|<flowtype_id>",
> >>>  	.tokens = {
> >>>  		(void *)&cmd_config_rss_port,
> >>>  		(void *)&cmd_config_rss_keyword,
> >>> @@ -2438,7 +2442,8 @@ struct cmd_config_rss_hash_key {
> >>>  				 "ipv6-tcp-ex#ipv6-udp-ex#"
> >>>  				 "l3-src-only#l3-dst-only#l4-src-only#l4-dst-only#"
> >>>  				 "l2-src-only#l2-dst-only#s-vlan#c-vlan#"
> >>> -				 "l2tpv3#esp#ah#pfcp#pppoe#gtpu#ecpri#mpls");
> >>> +				 "l2tpv3#esp#ah#pfcp#pppoe#gtpu#ecpri#mpls#"
> >>> +				 "ipv4-chksum#l4-chksum");
> >>>  cmdline_parse_token_string_t cmd_config_rss_hash_key_value =
> >>>  	TOKEN_STRING_INITIALIZER(struct cmd_config_rss_hash_key, key,
> >>> NULL);
> >>>
> >>> @@ -2451,7 +2456,8 @@ struct cmd_config_rss_hash_key {
> >>>  		"l2-payload|ipv6-ex|ipv6-tcp-ex|ipv6-udp-ex|"
> >>>  		"l3-src-only|l3-dst-only|l4-src-only|l4-dst-only|"
> >>>  		"l2-src-only|l2-dst-only|s-vlan|c-vlan|"
> >>> -		"l2tpv3|esp|ah|pfcp|pppoe|gtpu|ecpri|mpls "
> >>> +		"l2tpv3|esp|ah|pfcp|pppoe|gtpu|ecpri|mpls|"
> >>> +		"ipv4-chksum|l4-chksum "
> >>>  		"<string of hex digits (variable length, NIC dependent)>",
> >>>  	.tokens = {
> >>>  		(void *)&cmd_config_rss_hash_key_port, diff --git
> >>> a/app/test-pmd/config.c b/app/test-pmd/config.c index
> >>> 43c79b5..14968bf
> >>> 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/lib/ethdev/rte_ethdev.h b/lib/ethdev/rte_ethdev.h index
> >>> faf3bd9..63b0321 100644
> >>> --- a/lib/ethdev/rte_ethdev.h
> >>> +++ b/lib/ethdev/rte_ethdev.h
> >>> @@ -537,6 +537,8 @@ 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)
> >>> +#define ETH_RSS_L4_CHKSUM	   (1ULL << 35)	/* TCP/UDP/SCTP */
> >>
> >> It does not reply on my questions at all.
> 
> Above list of Layer 4 protocols does not say if the flag may be reported when all
> above protocols are supported or some protocols are supported only.
> 
> Also I had a question about UDP checksum 0 since it could be treated in a
> different ways since logically it is no checksum at all.

I'll add comment for UDP checksum in next patch.   
Thanks.   

> 
> > You have said:
> >>>> I don't think so. IMHO, it should report all RSS capabilities
> >>>> regardless generic vs flow API RSS action.
> >>>
> >> May be it is OK to report subset in
> >> dev_info->flow_type_rss_offloads, but I'm very uncomfortable with the
> >> approach. Superset sounds more logical to me, but has drawbacks as
> >> well.
> >
> > Here I have another question:
> > There are flow type definition and RSS offload type definition,
> > #define RTE_ETH_FLOW_RAW                 1
> > #define RTE_ETH_FLOW_IPV4                2
> > #define RTE_ETH_FLOW_FRAG_IPV4           3
> > #define RTE_ETH_FLOW_NONFRAG_IPV4_TCP    4
> >
> > #define ETH_RSS_IPV4               (1ULL << 2)
> > #define ETH_RSS_FRAG_IPV4          (1ULL << 3)
> > #define ETH_RSS_NONFRAG_IPV4_TCP   (1ULL << 4)
> >
> > are they the different expressions of the same concept?
> 
> Sorry, but I don't understand the question.
> 
> >
> > If yes, why they have been decoupled by the commit: fce6b66893.
> 
> Do you mean that motivation in the changeset description is not clear?
> 
> > Then what the flow type of ETH_RSS_PORT, it's UDP, TCP, or SCTP?
> 
> I have no answer to the question as well. That's why I'm trying to avoid it in the
> patch.

IMHO, the flow type is different from RSS Offload type.  
That's why they have been decoupled in commit fce6b66893   
    ethdev: decouple flow types and RSS offload types   

    This patch decouples RTE_ETH_FLOW_* and ETH_RSS_*. The former defines   
    flow types and the latter defines RSS offload types.   

There are total 25 flow types, but 30+ RSS offload types.  
The PMDs report flow type in dev_info->flow_type_rss_offloads, but they don't report RSS offload type.   

> 
> >
> > If not, the PMDs can report supported RSS flow type by
> dev_info->flow_type_rss_offloads,
> > but have no way to report supported RSS offload types.
> 
> Sorry, don't understand.
> 
> >>
> >> Nack