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

[fengchengwen <fengchengwen@huawei.com>]

On 2023/2/14 2:18, Ferruh Yigit wrote:
> 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.

Done it v3.

> 
>> +		*(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?

Both done in v3.

Thanks.

> 
>> +			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");
> 
> .
>