RE: [PATCH] examples/l3fwd: support setting the data size of mbuf

["Morten Brørup" <mb@smartsharesystems.com>]

> From: Chaoyong He [mailto:chaoyong.he@corigine.com]
> Sent: Wednesday, 16 October 2024 10.23
> 
> From: Long Wu <long.wu@corigine.com>
> 
> The previous code used a macro as the data size for mbuf
> to create the mempool and users cannot modify the size.
> 
> Now modify the code to support setting the data size of
> mbuf by '--mbuf-size' parameter. If user does not add the
> parameter in start command line, the default size is still
> 'RTE_MBUF_DEFAULT_BUF_SIZE'.
> 
> Examples:
> dpdk-l3fwd -l 0-3 -- -p 0x03 --mbuf-size=4096
> 
> Signed-off-by: Long Wu <long.wu@corigine.com>
> Reviewed-by: Chaoyong He <chaoyong.he@corigine.com>
> ---
>  examples/l3fwd/main.c | 17 ++++++++++++++---
>  1 file changed, 14 insertions(+), 3 deletions(-)
> 
> diff --git a/examples/l3fwd/main.c b/examples/l3fwd/main.c
> index 01b763e5ba..ccce16c6bb 100644
> --- a/examples/l3fwd/main.c
> +++ b/examples/l3fwd/main.c
> @@ -140,6 +140,7 @@ uint32_t max_pkt_len;
>  #ifdef RTE_LIB_EVENTDEV
>  static struct rte_mempool *vector_pool[RTE_MAX_ETHPORTS];
>  #endif
> +static uint16_t mbuf_seg_size = RTE_MBUF_DEFAULT_BUF_SIZE;

Prefer variable using same offset as command line parameter:
static uint16_t mbuf_data_size = RTE_MBUF_DEFAULT_DATAROOM;

>  static struct rte_mempool *pktmbuf_pool[RTE_MAX_ETHPORTS][NB_SOCKETS];
>  static uint8_t lkp_per_socket[NB_SOCKETS];
> 
> @@ -448,7 +449,8 @@ print_usage(const char *prgname)
>  		"                    One is ACL entry at while line leads
> with character '%c',\n"
>  		"                    another is route entry at while line
> leads with character '%c'.\n"
>  		"  --rule_ipv6=FILE: Specify the ipv6 rules entries
> file.\n"
> -		"  --alg: ACL classify method to use, one of: %s.\n\n",
> +		"  --alg: ACL classify method to use, one of: %s.\n"
> +		"  --mbuf-size=N: Set the data size of mbuf to N
> bytes.\n\n",
>  		prgname, RX_DESC_DEFAULT, TX_DESC_DEFAULT,
>  		ACL_LEAD_CHAR, ROUTE_LEAD_CHAR, alg);
>  }
> @@ -698,6 +700,7 @@ static const char short_options[] =
>  #define CMD_LINE_OPT_RULE_IPV4 "rule_ipv4"
>  #define CMD_LINE_OPT_RULE_IPV6 "rule_ipv6"
>  #define CMD_LINE_OPT_ALG "alg"
> +#define CMD_LINE_OPT_MBUF_SIZE "mbuf-size"
> 
>  enum {
>  	/* long options mapped to a short option */
> @@ -726,7 +729,8 @@ enum {
>  	CMD_LINE_OPT_LOOKUP_NUM,
>  	CMD_LINE_OPT_ENABLE_VECTOR_NUM,
>  	CMD_LINE_OPT_VECTOR_SIZE_NUM,
> -	CMD_LINE_OPT_VECTOR_TMO_NS_NUM
> +	CMD_LINE_OPT_VECTOR_TMO_NS_NUM,
> +	CMD_LINE_OPT_MBUF_SIZE_NUM,
>  };
> 
>  static const struct option lgopts[] = {
> @@ -753,6 +757,7 @@ static const struct option lgopts[] = {
>  	{CMD_LINE_OPT_RULE_IPV4,   1, 0, CMD_LINE_OPT_RULE_IPV4_NUM},
>  	{CMD_LINE_OPT_RULE_IPV6,   1, 0, CMD_LINE_OPT_RULE_IPV6_NUM},
>  	{CMD_LINE_OPT_ALG,   1, 0, CMD_LINE_OPT_ALG_NUM},
> +	{CMD_LINE_OPT_MBUF_SIZE, 1, 0, CMD_LINE_OPT_MBUF_SIZE_NUM},
>  	{NULL, 0, 0, 0}
>  };
> 
> @@ -934,6 +939,12 @@ parse_args(int argc, char **argv)
>  		case CMD_LINE_OPT_ALG_NUM:
>  			l3fwd_set_alg(optarg);
>  			break;
> +		case CMD_LINE_OPT_MBUF_SIZE_NUM:
> +			mbuf_seg_size = strtoul(optarg, NULL, 10) +
> RTE_PKTMBUF_HEADROOM;
> +			if (mbuf_seg_size <= 0 || mbuf_seg_size > 0xFFFF)
> +				rte_exit(EXIT_FAILURE,
> +						"mbuf-size should be > 0 and <
> 65536\n");

mbuf_data_size = strtoul(optarg, NULL, 10);
if (mbuf_data_size == ULONG_MAX)
	rte_exit(EXIT_FAILURE, "mbuf-size should be a number\n");
if (mbuf_data_size < RTE_ETHER_MIN_LEN ||
		mbuf_data_size > 0xFFFF - RTE_PKTMBUF_HEADROOM)
	rte_exit(EXIT_FAILURE,
			"mbuf-size should be >= %u and <= %u\n",
			RTE_ETHER_MIN_LEN, 0xFFFF - RTE_PKTMBUF_HEADROOM);

> +			break;
>  		default:
>  			print_usage(prgname);
>  			return -1;
> @@ -1034,7 +1045,7 @@ init_mem(uint16_t portid, unsigned int nb_mbuf)
>  			pktmbuf_pool[portid][socketid] =
>  				rte_pktmbuf_pool_create(s, nb_mbuf,
>  					MEMPOOL_CACHE_SIZE, 0,
> -					RTE_MBUF_DEFAULT_BUF_SIZE, socketid);
> +					mbuf_seg_size, socketid);

mbuf_data_size + RTE_PKTMBUF_HEADROOM, socketid);

>  			if (pktmbuf_pool[portid][socketid] == NULL)
>  				rte_exit(EXIT_FAILURE,
>  					"Cannot init mbuf pool on socket %d\n",
> --
> 2.39.1

With above changes,
Acked-by: Morten Brørup <mb@smartsharesystems.com>