Re: [PATCH v2] ethdev: telemetry xstats support hide zero

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

On 2/13/2023 2:34 AM, Chengwen Feng wrote:
> The number of xstats may be large, after the hide zero option is added,
> only non-zero values can be displayed.
> 
> So display xstats with hide zero:
> 	/ethdev/xstats,0,hide_zero=true
> and without hide zero (same as the original):
> 	/ethdev/xstats,0
> 
> Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
> 
> ---
> v2: using hide_zero=true optional parameter which address Ferruh's
> comments.
> 
> ---
>  lib/ethdev/rte_ethdev.c | 38 ++++++++++++++++++++++++++++++++------
>  1 file changed, 32 insertions(+), 6 deletions(-)
> 
> diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c
> index d25db35f7f..7e70292fc6 100644
> --- a/lib/ethdev/rte_ethdev.c
> +++ b/lib/ethdev/rte_ethdev.c
> @@ -15,6 +15,7 @@
>  #include <bus_driver.h>
>  #include <rte_log.h>
>  #include <rte_interrupts.h>
> +#include <rte_kvargs.h>
>  #include <rte_memcpy.h>
>  #include <rte_common.h>
>  #include <rte_mempool.h>
> @@ -5863,6 +5864,18 @@ eth_dev_handle_port_stats(const char *cmd __rte_unused,
>  	return 0;
>  }
>  
> +#define TEL_XSTATS_HIDE_ZERO_KEY	"hide_zero"
> +#define TEL_XSTATS_HIDE_ZERO_VAL	"true"
> +
> +static int
> +eth_dev_parse_hide_zero(const char *key, const char *value, void *extra_args)
> +{
> +	RTE_SET_USED(key);
> +	if (strcmp(value, TEL_XSTATS_HIDE_ZERO_VAL) == 0)


kvargs allows to provide parameter without value, like
'/ethdev/xstats,0,hide_zero'

In this case 'value' will be NULL and this cause a crash in dpdk
application.
Better to check that 'value' is not NULL before using it.

> +		*(bool *)extra_args = true;
> +	return 0;
> +}
> +
>  static int
>  eth_dev_handle_port_xstats(const char *cmd __rte_unused,
>  		const char *params,
> @@ -5870,20 +5883,30 @@ eth_dev_handle_port_xstats(const char *cmd __rte_unused,
>  {
>  	struct rte_eth_xstat *eth_xstats;
>  	struct rte_eth_xstat_name *xstat_names;
> +	struct rte_kvargs *kvlist;
>  	int port_id, num_xstats;
> -	int i, ret;
> +	bool hide_zero = false;
>  	char *end_param;
> +	int i, ret;
>  
>  	if (params == NULL || strlen(params) == 0 || !isdigit(*params))
>  		return -1;
>  
>  	port_id = strtoul(params, &end_param, 0);
> -	if (*end_param != '\0')
> -		RTE_ETHDEV_LOG(NOTICE,
> -			"Extra parameters passed to ethdev telemetry command, ignoring");
>  	if (!rte_eth_dev_is_valid_port(port_id))
>  		return -1;
>  
> +	if (*end_param != '\0') {
> +		kvlist = rte_kvargs_parse(end_param, NULL);
> +		if (kvlist != NULL)
> +			rte_kvargs_process(kvlist, TEL_XSTATS_HIDE_ZERO_KEY,
> +					   eth_dev_parse_hide_zero, &hide_zero);
> +		if (kvlist == NULL || !hide_zero || kvlist->count > 1)

Instead of "kvlist->count > 1" can be better to use 'valid_keys'
argument of 'rte_kvargs_parse()' to detect extra parameters, this way
multiple 'hide_zero' parameters or future expansion of args won't be
blocked.


Similarly, '!hide_zero' check prevents "hide_zero=false" usage, it is
not documented but this is expected to be supported intuitively, perhaps
can be better to support "hide_zero=false" fully, document it and remove
'!hide_zero' from check?

> +			RTE_ETHDEV_LOG(NOTICE,
> +				"Unknown extra parameters passed to ethdev telemetry command, ignoring\n");
> +		rte_kvargs_free(kvlist);
> +	}
> +
>  	num_xstats = rte_eth_xstats_get(port_id, NULL, 0);
>  	if (num_xstats < 0)
>  		return -1;
> @@ -5908,9 +5931,12 @@ eth_dev_handle_port_xstats(const char *cmd __rte_unused,
>  	}
>  
>  	rte_tel_data_start_dict(d);
> -	for (i = 0; i < num_xstats; i++)
> +	for (i = 0; i < num_xstats; i++) {
> +		if (hide_zero && eth_xstats[i].value == 0)
> +			continue;
>  		rte_tel_data_add_dict_uint(d, xstat_names[i].name,
>  					   eth_xstats[i].value);
> +	}
>  	free(eth_xstats);
>  	return 0;
>  }
> @@ -6328,7 +6354,7 @@ RTE_INIT(ethdev_init_telemetry)
>  	rte_telemetry_register_cmd("/ethdev/stats", eth_dev_handle_port_stats,
>  			"Returns the common stats for a port. Parameters: int port_id");
>  	rte_telemetry_register_cmd("/ethdev/xstats", eth_dev_handle_port_xstats,
> -			"Returns the extended stats for a port. Parameters: int port_id");
> +			"Returns the extended stats for a port. Parameters: int port_id,hide_zero=true(Optional for indicates hide zero xstats)");
>  #ifndef RTE_EXEC_ENV_WINDOWS
>  	rte_telemetry_register_cmd("/ethdev/dump_priv", eth_dev_handle_port_dump_priv,
>  			"Returns dump private information for a port. Parameters: int port_id");