Re: [dpdk-dev] [PATCH 2/6] fib: make lookup function type configurable

["Medvedkin, Vladimir" <vladimir.medvedkin@intel.com>]

Hi Ray,


-----Original Message-----
From: Ray Kinsella <mdr@ashroe.eu> 
Sent: Wednesday, April 1, 2020 6:48 AM
To: Medvedkin, Vladimir <vladimir.medvedkin@intel.com>; dev@dpdk.org
Cc: Ananyev, Konstantin <konstantin.ananyev@intel.com>; Richardson, Bruce <bruce.richardson@intel.com>
Subject: Re: [dpdk-dev] [PATCH 2/6] fib: make lookup function type configurable

Hi Vladimir,

On 09/03/2020 12:43, Vladimir Medvedkin wrote:
> Add type argument to dir24_8_get_lookup_fn() Now it supports 3 
> different lookup implementations:
>  RTE_FIB_DIR24_8_SCALAR_MACRO
>  RTE_FIB_DIR24_8_SCALAR_INLINE
>  RTE_FIB_DIR24_8_SCALAR_UNI
> 
> Add new rte_fib_set_lookup_fn() - user can change lookup function type 
> runtime.
> 
> Signed-off-by: Vladimir Medvedkin <vladimir.medvedkin@intel.com>
> ---
>  lib/librte_fib/dir24_8.c           | 32 ++++++++++++++++++++------------
>  lib/librte_fib/dir24_8.h           |  2 +-
>  lib/librte_fib/rte_fib.c           | 20 +++++++++++++++++++-
>  lib/librte_fib/rte_fib.h           | 22 ++++++++++++++++++++++
>  lib/librte_fib/rte_fib_version.map |  1 +
>  5 files changed, 63 insertions(+), 14 deletions(-)
> 
> diff --git a/lib/librte_fib/dir24_8.c b/lib/librte_fib/dir24_8.c index 
> c9dce3c..825d061 100644
> --- a/lib/librte_fib/dir24_8.c
> +++ b/lib/librte_fib/dir24_8.c
> @@ -45,13 +45,6 @@ struct dir24_8_tbl {
>  
>  #define ROUNDUP(x, y)	 RTE_ALIGN_CEIL(x, (1 << (32 - y)))
>  
> -enum lookup_type {
> -	MACRO,
> -	INLINE,
> -	UNI
> -};
> -enum lookup_type test_lookup = MACRO;
> -
>  static inline void *
>  get_tbl24_p(struct dir24_8_tbl *dp, uint32_t ip, uint8_t nh_sz)  { @@ 
> -253,11 +246,18 @@ dir24_8_lookup_bulk_uni(void *p, const uint32_t 
> *ips,  }
>  
>  rte_fib_lookup_fn_t
> -dir24_8_get_lookup_fn(struct rte_fib_conf *fib_conf)
> +dir24_8_get_lookup_fn(void *p, enum rte_fib_dir24_8_lookup_type type)
>  {
> -	enum rte_fib_dir24_8_nh_sz nh_sz = fib_conf->dir24_8.nh_sz;
> +	enum rte_fib_dir24_8_nh_sz nh_sz;
> +	struct dir24_8_tbl *dp = p;
>  
> -	if (test_lookup == MACRO) {
> +	if (dp == NULL)
> +		return NULL;
> +
> +	nh_sz = dp->nh_sz;
> +
> +	switch (type) {
> +	case RTE_FIB_DIR24_8_SCALAR_MACRO:
>  		switch (nh_sz) {
>  		case RTE_FIB_DIR24_8_1B:
>  			return dir24_8_lookup_bulk_1b;
> @@ -267,8 +267,10 @@ dir24_8_get_lookup_fn(struct rte_fib_conf *fib_conf)
>  			return dir24_8_lookup_bulk_4b;
>  		case RTE_FIB_DIR24_8_8B:
>  			return dir24_8_lookup_bulk_8b;
> +		default:
> +			return NULL;
>  		}
> -	} else if (test_lookup == INLINE) {
> +	case RTE_FIB_DIR24_8_SCALAR_INLINE:
>  		switch (nh_sz) {
>  		case RTE_FIB_DIR24_8_1B:
>  			return dir24_8_lookup_bulk_0;
> @@ -278,9 +280,15 @@ dir24_8_get_lookup_fn(struct rte_fib_conf *fib_conf)
>  			return dir24_8_lookup_bulk_2;
>  		case RTE_FIB_DIR24_8_8B:
>  			return dir24_8_lookup_bulk_3;
> +		default:
> +			return NULL;
>  		}
> -	} else
> +	case RTE_FIB_DIR24_8_SCALAR_UNI:
>  		return dir24_8_lookup_bulk_uni;
> +	default:
> +		return NULL;
> +	}
> +
>  	return NULL;
>  }
>  
> diff --git a/lib/librte_fib/dir24_8.h b/lib/librte_fib/dir24_8.h index 
> 1ec437c..53c5dd2 100644
> --- a/lib/librte_fib/dir24_8.h
> +++ b/lib/librte_fib/dir24_8.h
> @@ -22,7 +22,7 @@ void
>  dir24_8_free(void *p);
>  
>  rte_fib_lookup_fn_t
> -dir24_8_get_lookup_fn(struct rte_fib_conf *conf);
> +dir24_8_get_lookup_fn(void *p, enum rte_fib_dir24_8_lookup_type 
> +type);
>  
>  int
>  dir24_8_modify(struct rte_fib *fib, uint32_t ip, uint8_t depth, diff 
> --git a/lib/librte_fib/rte_fib.c b/lib/librte_fib/rte_fib.c index 
> e090808..59120b5 100644
> --- a/lib/librte_fib/rte_fib.c
> +++ b/lib/librte_fib/rte_fib.c
> @@ -107,7 +107,8 @@ init_dataplane(struct rte_fib *fib, __rte_unused int socket_id,
>  		fib->dp = dir24_8_create(dp_name, socket_id, conf);
>  		if (fib->dp == NULL)
>  			return -rte_errno;
> -		fib->lookup = dir24_8_get_lookup_fn(conf);
> +		fib->lookup = dir24_8_get_lookup_fn(fib->dp,
> +			RTE_FIB_DIR24_8_SCALAR_MACRO);
>  		fib->modify = dir24_8_modify;
>  		return 0;
>  	default:
> @@ -317,3 +318,20 @@ rte_fib_get_rib(struct rte_fib *fib)  {
>  	return (fib == NULL) ? NULL : fib->rib;  }
> +
> +int
> +rte_fib_set_lookup_fn(struct rte_fib *fib, int type) {
> +	rte_fib_lookup_fn_t fn;
> +
> +	switch (fib->type) {
> +	case RTE_FIB_DIR24_8:
> +		fn = dir24_8_get_lookup_fn(fib->dp, type);
> +		if (fn == NULL)
> +			return -EINVAL;
> +		fib->lookup = fn;
> +		return 0;
> +	default:
> +		return -EINVAL;
> +	}
> +}
> diff --git a/lib/librte_fib/rte_fib.h b/lib/librte_fib/rte_fib.h index 
> d06c5ef..0e98775 100644
> --- a/lib/librte_fib/rte_fib.h
> +++ b/lib/librte_fib/rte_fib.h
> @@ -47,6 +47,12 @@ enum rte_fib_dir24_8_nh_sz {
>  	RTE_FIB_DIR24_8_8B
>  };
Do we provide the user guidance anywhere on the merits/advantages of each option?

No, we don't at the moment. I covered this in my slides about FIB. In my ToDo I have a plan to add documentation for this library and I will reflect this option there.

> +enum rte_fib_dir24_8_lookup_type {
> +	RTE_FIB_DIR24_8_SCALAR_MACRO,
> +	RTE_FIB_DIR24_8_SCALAR_INLINE,
> +	RTE_FIB_DIR24_8_SCALAR_UNI
> +};
> +
>  /** FIB configuration structure */
>  struct rte_fib_conf {
>  	enum rte_fib_type type; /**< Type of FIB struct */ @@ -185,4 +191,20 
> @@ __rte_experimental  struct rte_rib *  rte_fib_get_rib(struct 
> rte_fib *fib);
>  
> +/**
> + * Set lookup function based on type
> + *
> + * @param fib
> + *   FIB object handle
> + * @param type
> + *   type of lookup function
> + *
> + * @return
> + *    -EINVAL on failure
> + *    0 on success
> + */
> +__rte_experimental
> +int
> +rte_fib_set_lookup_fn(struct rte_fib *fib, int type);
> +
>  #endif /* _RTE_FIB_H_ */
> diff --git a/lib/librte_fib/rte_fib_version.map 
> b/lib/librte_fib/rte_fib_version.map
> index 9527417..216af66 100644
> --- a/lib/librte_fib/rte_fib_version.map
> +++ b/lib/librte_fib/rte_fib_version.map
> @@ -9,6 +9,7 @@ EXPERIMENTAL {
>  	rte_fib_lookup_bulk;
>  	rte_fib_get_dp;
>  	rte_fib_get_rib;
> +	rte_fib_set_lookup_fn;
>  
>  	rte_fib6_add;
>  	rte_fib6_create;
>