Re: [dpdk-dev] [PATCH] app/testpmd: fix segment number check

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

On 12/11/2020 3:07 PM, Viacheslav Ovsiienko wrote:
> The --txpkts command line parameter was silently ignored due to
> application was unable to check the Tx queue ring sizes for non
> configured ports [1].
> 
> The "set txpkts <len0[,len1]*>" was also rejected if there
> was some stopped or /unconfigured port.
> 

May not be for the commit log but to understand the problem here,
what are the steps to reproduce the problem in "set txpkts" command?

> This provides the following:
> 
>    - number of segment check is performed against
>      configured Tx queues only
> 
>    - the capability to send single packet is supposed to
>      be very basic and always supported, the setting segment
>      number to 1 is always allowed, no check performed
> 
>    - at the moment of Tx queue setup the descriptor number is
>      checked against configured segment number

Not sure about this one, more comments below.

> 
> Fixes: 8dae835d88b7 ("app/testpmd: remove restriction on Tx segments set")
> Cc: stable@dpdk.org
> Bugzilla ID: 584
> 
> Signed-off-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
> ---
>   app/test-pmd/cmdline.c |  5 +++++
>   app/test-pmd/config.c  | 21 ++++++++++++++++-----
>   app/test-pmd/testpmd.c |  7 ++++++-
>   3 files changed, 27 insertions(+), 6 deletions(-)
> 
> diff --git a/app/test-pmd/cmdline.c b/app/test-pmd/cmdline.c
> index 0d2d6aa..86388a2 100644
> --- a/app/test-pmd/cmdline.c
> +++ b/app/test-pmd/cmdline.c
> @@ -2798,6 +2798,11 @@ struct cmd_setup_rxtx_queue {
>   		if (!numa_support || socket_id == NUMA_NO_CONFIG)
>   			socket_id = port->socket_id;
>   
> +		if (port->nb_tx_desc[res->qid] < tx_pkt_nb_segs) {
> +			printf("Failed to setup TX queue: "
> +			       "not enough descriptors\n");
> +			return;
> +		}

The "port->nb_tx_desc[res->qid]" can be '0', and that is the default value in 
the testpmd, in that case device suggested values are used. Above check fails 
when '--txd' arguments is not provided.
Same problem with the same check below in 'start_port()', I think both can be 
removed.

>   		ret = rte_eth_tx_queue_setup(res->portid,
>   					     res->qid,
>   					     port->nb_tx_desc[res->qid],
> diff --git a/app/test-pmd/config.c b/app/test-pmd/config.c
> index b51de59..a6fccfa 100644
> --- a/app/test-pmd/config.c
> +++ b/app/test-pmd/config.c
> @@ -3911,12 +3911,18 @@ struct igb_ring_desc_16_bytes {
>   		for (queue_id = 0; queue_id < nb_txq; queue_id++) {
>   			ret = get_tx_ring_size(port_id, queue_id, &ring_size);
>   
> -			if (ret)
> +			/* Do the check only for the active/configured ports. */
> +			if (ret == -EINVAL)
> +				continue;
> +			if (ret) {
> +				printf("failed to get ring size for TX "
> +				       "queue(%u) Port(%u) - txpkts ignored\n",
> +				       port_id, queue_id);
>   				return true;

Is there a need to filter the '-EINVAL' errors only, the other error this 
function can get is '-EINVAL' & '-ENODEV' (which is 'port_id' is not valid), to 
simplify the logic, what do you think just ignore any kind of error and not fail 
in that case?

> -
> +			}
>   			if (ring_size < nb_segs) {
> -				printf("nb segments per TX packets=%u >= "
> -				       "TX queue(%u) ring_size=%u - ignored\n",
> +				printf("nb segments per TX packets=%u >= TX "
> +				       "queue(%u) ring_size=%u - txpkts ignored\n",
>   				       nb_segs, queue_id, ring_size);
>   				return true;
>   			}
> @@ -3932,7 +3938,12 @@ struct igb_ring_desc_16_bytes {
>   	uint16_t tx_pkt_len;
>   	unsigned int i;
>   
> -	if (nb_segs_is_invalid(nb_segs))
> +	/*
> +	 * For single sengment settings failed check is ignored.
> +	 * It is a very basic capability to send the single segment
> +	 * packets, suppose it is always supported.
> +	 */
> +	if (nb_segs > 1 && nb_segs_is_invalid(nb_segs))
>   		return;

if the user provided '--txd' in the command line, we can compare the segment 
size with that without going into the device configured values, as similar to 
what is done before:

At the very beginning of the 'get_tx_ring_size()':

if (nb_txd) {
   *ring_size = nb_txd;
   return 0;
}

So following combination of parameters will be supported

"--txpkts=X,Y --txd=Z"  (segment size checked against nb_txd)
"--txpkts=N "           (single segment, no check)
"--txpkts=X,Y"          (segment size not checked)

And setting same in the command line always should be supported with segment 
size checks against the
- nb_txd when '--txd=Z' provided
- dynamic device provided values when '--txd=Z' not provided

>   
>   	/*
> diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c
> index 33fc0fd..9ea0145 100644
> --- a/app/test-pmd/testpmd.c
> +++ b/app/test-pmd/testpmd.c
> @@ -2575,6 +2575,11 @@ struct extmem_param {
>   			port->need_reconfig_queues = 0;
>   			/* setup tx queues */
>   			for (qi = 0; qi < nb_txq; qi++) {
> +				if (port->nb_tx_desc[qi] < tx_pkt_nb_segs) {
> +					printf("Failed to setup TX queue: "
> +					       "not enough descriptors\n");
> +					goto fail;
> +				}

Please check above comment.

>   				if ((numa_support) &&
>   					(txring_numa[pi] != NUMA_NO_CONFIG))
>   					diag = rte_eth_tx_queue_setup(pi, qi,
> @@ -2589,7 +2594,7 @@ struct extmem_param {
>   
>   				if (diag == 0)
>   					continue;
> -
> +fail:
>   				/* Fail to setup tx queue, return */
>   				if (rte_atomic16_cmpset(&(port->port_status),
>   							RTE_PORT_HANDLING,
>