Re: [dpdk-dev] [PATCH v4 2/2] app/testpmd: fix max-pkt-len option invalid

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 1/25/2021 8:32 AM, Steve Yang wrote:
> Moved the setting of 'DEV_RX_OFFLOAD_JUMBO_FRAME' from
> 'cmd_config_max_pkt_len_parsed()' to 'init_config()' caused fail the case
> where 'max_rx_pkt_len' is changed from the command line via
> "port config all max-pkt-len".
> 
> The 'init_config()' function is only called when testpmd is started,
> but the DEV_RX_OFFLOAD_JUMBO_FRAME setting needs to be recomputed whenever
> 'max_rx_pkt_len' changes.
> 
> Define the 'update_jumbo_frame_offload()' function for both 'init_config()'
> and 'cmd_config_max_pkt_len_parsed()', and detect if 'max_rx_pkt_len'
> should be update to 1500 + overhead as default configuration. At the same
> time, the offloads of rx queue also should update the value once port
> offloads changed (e.g.: disabled JUMBO_FRAME offload via changed
> max-pkt-len, reproduce steps [1]), otherwise, it would cause unexpected
> result.
> 
> [1]
> --------------------------------------------------------------------------
> ./x86_64-native-linuxapp-gcc/app/dpdk-testpmd  -c 0xf -n 4  -- -i
>      --max-pkt-len=9000 --tx-offloads=0x8000 --rxq=4 --txq=4 --disable-rss
> testpmd>  set verbose 3
> testpmd>  port stop all
> testpmd>  port config all max-pkt-len 1518  port start all
> 
> // Got fail error info without this patch
> Configuring Port 0 (socket 1)
> Ethdev port_id=0 rx_queue_id=0, new added offloads 0x800 must be
> within per-queue offload capabilities 0x0 in rte_eth_rx_queue_setup()
> Fail to configure port 0 rx queues //<-- Fail error info;
> --------------------------------------------------------------------------
> 
> Fixes: 761c4d6690 ("app/testpmd: fix max Rx packet length for VLAN packets")
> 
> Signed-off-by: Steve Yang <stevex.yang@intel.com>
> ---
>   app/test-pmd/cmdline.c    |  1 +
>   app/test-pmd/parameters.c |  1 +
>   app/test-pmd/testpmd.c    | 63 ++++++++++++++++++++++++++++-----------
>   app/test-pmd/testpmd.h    |  2 ++
>   4 files changed, 50 insertions(+), 17 deletions(-)
> 
> diff --git a/app/test-pmd/cmdline.c b/app/test-pmd/cmdline.c
> index 89034c8b72..8b6b7b6206 100644
> --- a/app/test-pmd/cmdline.c
> +++ b/app/test-pmd/cmdline.c
> @@ -1901,6 +1901,7 @@ cmd_config_max_pkt_len_parsed(void *parsed_result,
>   			printf("Unknown parameter\n");
>   			return;
>   		}
> +		update_jumbo_frame_offload(pid, false);
>   	}
>   
>   	init_port_config();
> diff --git a/app/test-pmd/parameters.c b/app/test-pmd/parameters.c
> index df5eb10d84..1c63156ddd 100644
> --- a/app/test-pmd/parameters.c
> +++ b/app/test-pmd/parameters.c
> @@ -833,6 +833,7 @@ launch_args_parse(int argc, char** argv)
>   						 "total-num-mbufs should be > 1024\n");
>   			}
>   			if (!strcmp(lgopts[opt_idx].name, "max-pkt-len")) {
> +				default_max_pktlen = false;
>   				n = atoi(optarg);
>   				if (n >= RTE_ETHER_MIN_LEN)
>   					rx_mode.max_rx_pkt_len = (uint32_t) n;
> diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c
> index c256e719ae..f22d2be46d 100644
> --- a/app/test-pmd/testpmd.c
> +++ b/app/test-pmd/testpmd.c
> @@ -531,6 +531,8 @@ uint16_t gso_max_segment_size = RTE_ETHER_MAX_LEN - RTE_ETHER_CRC_LEN;
>   /* Holds the registered mbuf dynamic flags names. */
>   char dynf_names[64][RTE_MBUF_DYN_NAMESIZE];
>   
> +bool default_max_pktlen = true;
> +
>   /*
>    * Helper function to check if socket is already discovered.
>    * If yes, return positive value. If not, return zero.
> @@ -1410,7 +1412,6 @@ init_config(void)
>   	struct rte_gro_param gro_param;
>   	uint32_t gso_types;
>   	uint16_t data_size;
> -	uint16_t eth_overhead;
>   	bool warning = 0;
>   	int k;
>   	int ret;
> @@ -1447,22 +1448,7 @@ init_config(void)
>   			rte_exit(EXIT_FAILURE,
>   				 "rte_eth_dev_info_get() failed\n");
>   
> -		/* Update the max_rx_pkt_len to have MTU as RTE_ETHER_MTU */
> -		if (port->dev_info.max_mtu != UINT16_MAX &&
> -		    port->dev_info.max_rx_pktlen > port->dev_info.max_mtu)
> -			eth_overhead = port->dev_info.max_rx_pktlen -
> -				port->dev_info.max_mtu;
> -		else
> -			eth_overhead =
> -				RTE_ETHER_HDR_LEN + RTE_ETHER_CRC_LEN;
> -
> -		if (port->dev_conf.rxmode.max_rx_pkt_len <=
> -			(uint32_t)(RTE_ETHER_MTU + eth_overhead))
> -			port->dev_conf.rxmode.max_rx_pkt_len =
> -					RTE_ETHER_MTU + eth_overhead;
> -		else
> -			port->dev_conf.rxmode.offloads |=
> -					DEV_RX_OFFLOAD_JUMBO_FRAME;
> +		update_jumbo_frame_offload(pid, default_max_pktlen);
>   
>   		if (!(port->dev_info.tx_offload_capa &
>   		      DEV_TX_OFFLOAD_MBUF_FAST_FREE))
> @@ -3358,6 +3344,49 @@ rxtx_port_config(struct rte_port *port)
>   	}
>   }
>   
> +void
> +update_jumbo_frame_offload(portid_t portid, bool def_max_pktlen)
> +{
> +	struct rte_port *port = &ports[portid];
> +	uint32_t eth_overhead;
> +	uint64_t rx_offloads;
> +
> +	/* Update the max_rx_pkt_len to have MTU as RTE_ETHER_MTU */
> +	if (port->dev_info.max_mtu != UINT16_MAX &&
> +	    port->dev_info.max_rx_pktlen > port->dev_info.max_mtu)
> +		eth_overhead = port->dev_info.max_rx_pktlen -
> +				port->dev_info.max_mtu;
> +	else
> +		eth_overhead = RTE_ETHER_HDR_LEN + RTE_ETHER_CRC_LEN;
> +
> +	rx_offloads = port->dev_conf.rxmode.offloads;
> +	if (port->dev_conf.rxmode.max_rx_pkt_len <=
> +		RTE_ETHER_MTU + eth_overhead) {

This check is also used to decide if expansion is required, but the check is 
generic, with "port config all max-pkt-len" command this condition always can be 
created.

The target is make testpmd set "RTE_ETHER_MTU + eth_overhead" instead of fixed 
'RTE_ETHER_MAX_LEN' value, so why not set initial '.max_rx_pkt_len' value to 
zero, to say extend it to the default value.

> +		/*
> +		 * If command line option doesn't include --max-pkt-len,
> +		 * the default max_rx_pkt_len should be set to 1500 + overhead.
> +		 */
> +		if (def_max_pktlen)
> +			port->dev_conf.rxmode.max_rx_pkt_len =
> +						RTE_ETHER_MTU + eth_overhead;

What if '--max-pkt-len' is not provided, but "port config all max-pkt-len" 
command issued, won't is discard the command and always set to default?

> +		rx_offloads &= ~DEV_RX_OFFLOAD_JUMBO_FRAME;
> +	} else
> +		rx_offloads |= DEV_RX_OFFLOAD_JUMBO_FRAME;
> +
> +	/* Apply Rx offloads configuration to Rx queue(s) */
> +	if (rx_offloads != port->dev_conf.rxmode.offloads) {
> +		uint16_t qid;
> +
> +		port->dev_conf.rxmode.offloads = rx_offloads;
> +		if (eth_dev_info_get_print_err(portid, &port->dev_info) != 0)
> +			rte_exit(EXIT_FAILURE,
> +				"rte_eth_dev_info_get() failed\n");
> +
> +		for (qid = 0; qid < port->dev_info.nb_rx_queues; qid++)
> +			port->rx_conf[qid].offloads = rx_offloads;

As said before, there is a concept of queue specific offloads, you can't just 
assume the queue offloads will always be same as the port offloads.
Instead it can be possible to add/remove JUMBO_FRAME offload to queues based on 
condition.

> +	}
> +}
> +
>   void
>   init_port_config(void)
>   {
> diff --git a/app/test-pmd/testpmd.h b/app/test-pmd/testpmd.h
> index 5f23162107..16f6fbefef 100644
> --- a/app/test-pmd/testpmd.h
> +++ b/app/test-pmd/testpmd.h
> @@ -304,6 +304,7 @@ extern cmdline_parse_inst_t cmd_show_set_raw_all;
>   
>   extern uint16_t mempool_flags;
>   
> +extern bool default_max_pktlen;
>   /**
>    * Forwarding Configuration
>    *
> @@ -1005,6 +1006,7 @@ uint16_t tx_pkt_set_dynf(uint16_t port_id, __rte_unused uint16_t queue,
>   			 __rte_unused void *user_param);
>   void add_tx_dynf_callback(portid_t portid);
>   void remove_tx_dynf_callback(portid_t portid);
> +void update_jumbo_frame_offload(portid_t portid, bool def_max_pktlen);
>   
>   /*
>    * Work-around of a compilation error with ICC on invocations of the
>