Re: [dpdk-dev] [PATCH v2 3/5] examples/kni: monitor and update link status continually

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

On 9/19/2018 8:55 PM, Dan Gora wrote:
> Update KNI example to continuously monitor the Ethernet link status of
> the physical link and update the carrier status of the corresponding
> interfaces with rte_kni_update_link().
> 
> Signed-off-by: Dan Gora <dg@adax.com>

Also this patch sets kni interfaces "up", please add this information to commit log.

<...>

> +	RTE_ETH_FOREACH_DEV(portid) {
> +		for (i = 0; i < p[portid]->nb_kni; i++) {
> +			name = rte_kni_get_name(p[portid]->kni[i]);
> +			snprintf(cmd, sizeof(cmd),
> +					"/sbin/ifconfig %s up", name);
> +			RTE_LOG(INFO, APP,
> +					"Marking interface %s 'up'\n", name);
> +			if (system(cmd) == -1)
> +				RTE_LOG(ERR, APP,
> +				  "Error: Failed to mark interface %s 'up'\n",
> +						name);
> +		}
> +	}

This part can be separated thread, overall already done only once, and put into
its own function. And what about making this optional with command line argument.

>  
> -	printf("\nChecking link status\n");
> -	fflush(stdout);
> -	for (count = 0; count <= MAX_CHECK_TIME; count++) {
> -		all_ports_up = 1;
> +	while (kni_running) {
> +		rte_delay_ms(CHECK_INTERVAL);
>  		RTE_ETH_FOREACH_DEV(portid) {
> -			if ((port_mask & (1 << portid)) == 0)
> +			if ((ports_mask & (1 << portid)) == 0)
>  				continue;
>  			memset(&link, 0, sizeof(link));
>  			rte_eth_link_get_nowait(portid, &link);
> -			/* print link status if flag set */
> -			if (print_flag == 1) {
> -				if (link.link_status)
> -					printf(
> -					"Port%d Link Up - speed %uMbps - %s\n",
> -						portid, link.link_speed,
> -				(link.link_duplex == ETH_LINK_FULL_DUPLEX) ?
> -					("full-duplex") : ("half-duplex\n"));
> -				else
> -					printf("Port %d Link Down\n", portid);
> -				continue;
> -			}
> -			/* clear all_ports_up flag if any link down */
> -			if (link.link_status == ETH_LINK_DOWN) {
> -				all_ports_up = 0;
> -				break;
> -			}
> -		}
> -		/* after finally printing all link status, get out */
> -		if (print_flag == 1)
> -			break;
> -
> -		if (all_ports_up == 0) {
> -			printf(".");
> -			fflush(stdout);
> -			rte_delay_ms(CHECK_INTERVAL);
> -		}

Previous logic makes sure all physical interfaces are up before packet
processing is started. Why removing this logic? I think it is good to keep it as
it is.

<...>

> @@ -947,7 +938,14 @@ main(int argc, char** argv)
>  
>  		kni_alloc(port);
>  	}
> -	check_all_ports_link_status(ports_mask);
> +
> +	kni_running = 1;
> +	ret = rte_ctrl_thread_create(&kni_link_tid,
> +				     "KNI link status check", NULL,
> +				     check_all_ports_link_status, NULL);

This thread is to reflect physical port link status to KNI interface, this can
be useful but not sure to have it as default. Why not introduce this ability,
and creating thread, as an optional feature enabled by command line option?

So overall makes two commandline option,
- one to set kni interfaces up by application
- one to create a thread to check and reflect physical port link status to KNI
interface