Re: [dpdk-dev] [PATCH v2 1/2] app/testpmd: support the heavywight mode GRO

[Jiayu Hu <jiayu.hu@intel.com>]

Hi Ferruh,

On Tue, Aug 22, 2017 at 09:30:32AM +0100, Ferruh Yigit wrote:
> On 8/22/2017 2:00 AM, Hu, Jiayu wrote:
> > Hi,
> >> -----Original Message-----
> >> From: Yigit, Ferruh
> >> Sent: Monday, August 21, 2017 7:04 PM
> >> To: Hu, Jiayu <jiayu.hu@intel.com>; dev@dpdk.org
> >> Cc: Ananyev, Konstantin <konstantin.ananyev@intel.com>; Tan, Jianfeng
> >> <jianfeng.tan@intel.com>; thomas@monjalon.net; Wu, Jingjing
> >> <jingjing.wu@intel.com>; Yao, Lei A <lei.a.yao@intel.com>
> >> Subject: Re: [PATCH v2 1/2] app/testpmd: support the heavywight mode GRO
> >>
> >> On 8/17/2017 10:08 AM, Jiayu Hu wrote:
> >>> The GRO library provides two reassembly modes: lightweight mode and
> >>> heavyweight mode. This patch is to support the heavyweight mode in
> >>> csum forwarding engine.
> >>>
> >>> With the command "set port <port_id> gro (heavymode|lightmode)
> >> (on|off)",
> >>> users can select the lightweight mode or the heavyweight mode to use.
> >> With
> >>> the command "set gro flush interval <num>", users can set the interval of
> >>> flushing GROed packets from reassembly tables for the heavyweight mode.
> >>> With the command "show port <port_id> gro", users can display GRO
> >>> configuration.
> >>>
> >>> Signed-off-by: Jiayu Hu <jiayu.hu@intel.com>
> >>
> >> <...>
> >>
> >>>  	lcoreid_t  cpuid_idx;    /**< index of logical core in CPU id table */
> >>> @@ -434,13 +436,21 @@ extern struct ether_addr
> >> peer_eth_addrs[RTE_MAX_ETHPORTS];
> >>>  extern uint32_t burst_tx_delay_time; /**< Burst tx delay time(us) for mac-
> >> retry. */
> >>>  extern uint32_t burst_tx_retry_num;  /**< Burst tx retry number for mac-
> >> retry. */
> >>>
> >>> +#define GRO_HEAVYMODE 0x1
> >>> +#define GRO_LIGHTMODE 0x2
> >>
> >> Why these are not part of the gro library?
> >> Is the concept "lightweight mode and heavyweight mode" part of gro
> >> library or implemented only in testpmd?
> > 
> > Lightweight mode and heavyweight mode are two reassembly methods we
> > provided in the GRO library. For applications, they are just two kinds of APIs.
> > Applications can select any of them to merge packets.
> 
> GRO modes are defined in testpmd, and kept in testpmd variables, library
> seems not aware of these modes.
> 
> What are these two APIs, rte_gro_reassemble() and
> rte_gro_reassemble_burst() ?
> Perhaps you can detail what Lightweight mode and heavyweight mode are,
> doc also don't have much about it.
> 
> This still looks like gro library provides common API and testpmd calls
> these API with different parameters and calls these lightweight and
> heavyweight, if these modes are common use case, I believe they should

Yes, the GRO API doesn't show the concept of 'heavyweight' and 'lightweight'.
This concept is only used to describe the supported reassembly modes in the
GRO library.

> be part of library. If not, instead of saying different gro modes, it
> can be presented as different gro usage samples in testpmd.

What does "different gro usage samples" mean? Different forwarding
engines?

> 
> testpmd good for testing dpdk, and good for providing usage sample for
> APIs, but I believe it shouldn't have the concepts coded in it,
> libraries should have it, that is what end user uses.
> 
> > 
> > In testpmd, we want to show how to use these two reassembly modes, so
> > I define two macros to present them. Users can select which one to use via
> > command line.
> > 
> >>
> >>> +
> >>>  #define GRO_DEFAULT_FLOW_NUM 4
> >>>  #define GRO_DEFAULT_ITEM_NUM_PER_FLOW DEF_PKT_BURST
> >>> +
> >>> +#define GRO_DEFAULT_FLUSH_INTERVAL 2
> >>> +#define GRO_MAX_FLUSH_INTERVAL 4
> >>> +
> >>>  struct gro_status {
> >>>  	struct rte_gro_param param;
> >>>  	uint8_t enable;
> >>>  };
> >>>  extern struct gro_status gro_ports[RTE_MAX_ETHPORTS];
> >>> +extern uint32_t gro_flush_interval;
> >>
> >> <...>