[dpdk-dev] [RFC PATCH v1 1/3] rte: change xstats to use integer keys

[David Harton (dharton)]

> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Remy Horton
> Sent: Friday, April 15, 2016 10:44 AM
> To: dev at dpdk.org; Thomas Monjalon <thomas.monjalon at 6wind.com>
> Subject: [dpdk-dev] [RFC PATCH v1 1/3] rte: change xstats to use integer
> keys
> 
> Signed-off-by: Remy Horton <remy.horton at intel.com>
> ---
>  lib/librte_ether/rte_ethdev.c | 87
> +++++++++++++++++++++++++++++++++++++++----
>  lib/librte_ether/rte_ethdev.h | 38 +++++++++++++++++++
>  2 files changed, 117 insertions(+), 8 deletions(-)
> 
> diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
> index a31018e..cdd0685 100644
> --- a/lib/librte_ether/rte_ethdev.c
> +++ b/lib/librte_ether/rte_ethdev.c
> @@ -1507,6 +1507,82 @@ rte_eth_stats_reset(uint8_t port_id)
>  	dev->data->rx_mbuf_alloc_failed = 0;
>  }
> 
> +static int
> +rte_eth_xstats_count(uint8_t port_id)

Thanks for adding this.  I believe an overt API is much more clear.

> +{
> +	struct rte_eth_dev *dev;
> +	int count;
> +
> +	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -EINVAL);
> +	dev = &rte_eth_devices[port_id];
> +	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->xstats_names, -ENOTSUP);
> +	count = (*dev->dev_ops->xstats_names)(dev, NULL, 0);
> +	if (count >= 0) {
> +		count += RTE_NB_STATS;
> +		count += dev->data->nb_rx_queues * RTE_NB_RXQ_STATS;
> +		count += dev->data->nb_tx_queues * RTE_NB_TXQ_STATS;
> +	}
> +	return count;
> +}
> +
> +int
> +rte_eth_xstats_names(uint8_t port_id, struct rte_eth_xstats_name
> *ptr_names,
> +	unsigned limit)
> +{
> +	struct rte_eth_dev *dev;
> +	int cnt_used_entries;
> +	int cnt_expected_entries;
> +	uint32_t idx, id_queue;
> +	int offset;
> +
> +	cnt_expected_entries = rte_eth_xstats_count(port_id);
> +	if (cnt_expected_entries < 0 || ptr_names == NULL)
> +		return cnt_expected_entries;

I suggest we don't provide two ways to get the number of stats and 
that users always call rte_eth_xstats_count().
Recommend returning -EINVAL if ptr_names is NULL.

> +
> +	if ((int)limit < cnt_expected_entries)
> +		return -ERANGE;
> +
> +	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -EINVAL);
> +	dev = &rte_eth_devices[port_id];
> +	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->xstats_names, -ENOTSUP);

I think this check is too restrictive.  There are drivers that do not 
provide device specific xstats today but the xstats API will still 
return the per q stats.
Recommend skipping the device specific steps that follow.

> +	cnt_used_entries = (*dev->dev_ops->xstats_names)(
> +		dev, ptr_names, limit);
> +
> +	if (cnt_used_entries < 0)
> +		return cnt_used_entries;
> +
> +	offset = cnt_used_entries * RTE_ETH_XSTATS_NAME_SIZE;
> +	for (idx = 0; idx < RTE_NB_STATS; idx++) {
> +		snprintf(ptr_names[cnt_used_entries].name,
> +			sizeof(ptr_names[0].name),
> +			"%s", rte_stats_strings[idx].name);
> +		offset += RTE_ETH_XSTATS_NAME_SIZE;
> +		cnt_used_entries++;
> +	}
> +	for (id_queue = 0; id_queue < dev->data->nb_rx_queues; id_queue++) {
> +		for (idx = 0; idx < RTE_NB_RXQ_STATS; idx++) {
> +			snprintf(ptr_names[cnt_used_entries].name,
> +				sizeof(ptr_names[0].name),
> +				"rx_q%u%s",
> +				id_queue, rte_rxq_stats_strings[idx].name);
> +			offset += RTE_ETH_XSTATS_NAME_SIZE;
> +			cnt_used_entries++;
> +		}
> +
> +	}
> +	for (id_queue = 0; id_queue < dev->data->nb_tx_queues; id_queue++) {
> +		for (idx = 0; idx < RTE_NB_TXQ_STATS; idx++) {
> +			snprintf(ptr_names[cnt_used_entries].name,
> +				sizeof(ptr_names[0].name),
> +				"tx_q%u%s",
> +				id_queue, rte_txq_stats_strings[idx].name);
> +			offset += RTE_ETH_XSTATS_NAME_SIZE;
> +			cnt_used_entries++;
> +		}
> +	}
> +	return cnt_used_entries;
> +}
> +
>  /* retrieve ethdev extended statistics */
>  int
>  rte_eth_xstats_get(uint8_t port_id, struct rte_eth_xstats *xstats,
> @@ -1551,8 +1627,7 @@ rte_eth_xstats_get(uint8_t port_id, struct
> rte_eth_xstats *xstats,
>  		stats_ptr = RTE_PTR_ADD(&eth_stats,
>  					rte_stats_strings[i].offset);
>  		val = *stats_ptr;
> -		snprintf(xstats[count].name, sizeof(xstats[count].name),
> -			"%s", rte_stats_strings[i].name);
> +		xstats[count].key = count + xcount;

Suggest setting adding:
xstats[count].name[0] = '\0'

until name is removed.

>  		xstats[count++].value = val;
>  	}
> 
> @@ -1563,9 +1638,7 @@ rte_eth_xstats_get(uint8_t port_id, struct
> rte_eth_xstats *xstats,
>  					rte_rxq_stats_strings[i].offset +
>  					q * sizeof(uint64_t));
>  			val = *stats_ptr;
> -			snprintf(xstats[count].name, sizeof(xstats[count].name),
> -				"rx_q%u_%s", q,
> -				rte_rxq_stats_strings[i].name);
> +			xstats[count].key = count + xcount;

Same name comment.

>  			xstats[count++].value = val;
>  		}
>  	}
> @@ -1577,9 +1650,7 @@ rte_eth_xstats_get(uint8_t port_id, struct
> rte_eth_xstats *xstats,
>  					rte_txq_stats_strings[i].offset +
>  					q * sizeof(uint64_t));
>  			val = *stats_ptr;
> -			snprintf(xstats[count].name, sizeof(xstats[count].name),
> -				"tx_q%u_%s", q,
> -				rte_txq_stats_strings[i].name);

Same name comment.

> +			xstats[count].key = count + xcount;
>  			xstats[count++].value = val;
>  		}
>  	}
> diff --git a/lib/librte_ether/rte_ethdev.h b/lib/librte_ether/rte_ethdev.h
> index 022733e..4b81c59 100644
> --- a/lib/librte_ether/rte_ethdev.h
> +++ b/lib/librte_ether/rte_ethdev.h
> @@ -941,10 +941,23 @@ struct rte_eth_txq_info {
>   * structure.
>   */
>  struct rte_eth_xstats {
> +	/* FIXME: Remove name[] once remaining drivers converted */
>  	char name[RTE_ETH_XSTATS_NAME_SIZE];
> +	uint64_t key;
>  	uint64_t value;
>  };
> 
> +/**
> + * A name-key lookup element for extended statistics.
> + *
> + * This structure is used to map between names and ID numbers
> + * for extended ethernet statistics.
> + */
> +struct rte_eth_xstats_name {
> +	char name[RTE_ETH_XSTATS_NAME_SIZE];
> +	uint64_t id;

Suggest naming this key as well or modifying rte_eth_xstats to use id.

> +};
> +
>  #define ETH_DCB_NUM_TCS    8
>  #define ETH_MAX_VMDQ_POOL  64
> 
> @@ -1080,6 +1093,10 @@ typedef int (*eth_xstats_get_t)(struct rte_eth_dev
> *dev,
>  typedef void (*eth_xstats_reset_t)(struct rte_eth_dev *dev);
>  /**< @internal Reset extended stats of an Ethernet device. */
> 
> +typedef int (*eth_xstats_names_t)(struct rte_eth_dev *dev,
> +	struct rte_eth_xstats_name *ptr_names, unsigned limit);
> +/**< @internal Get names of extended stats of an Ethernet device. */
> +
>  typedef int (*eth_queue_stats_mapping_set_t)(struct rte_eth_dev *dev,
>  					     uint16_t queue_id,
>  					     uint8_t stat_idx,
> @@ -1427,6 +1444,8 @@ struct eth_dev_ops {
>  	eth_stats_reset_t          stats_reset;   /**< Reset generic device
> statistics. */
>  	eth_xstats_get_t           xstats_get;    /**< Get extended device
> statistics. */
>  	eth_xstats_reset_t         xstats_reset;  /**< Reset extended device
> statistics. */
> +	eth_xstats_names_t         xstats_names;
> +	/**< Get names of extended statistics. */
>  	eth_queue_stats_mapping_set_t queue_stats_mapping_set;
>  	/**< Configure per queue stat counter mapping. */
>  	eth_dev_infos_get_t        dev_infos_get; /**< Get device info. */
> @@ -2279,6 +2298,25 @@ int rte_eth_stats_get(uint8_t port_id, struct
> rte_eth_stats *stats);
>  void rte_eth_stats_reset(uint8_t port_id);
> 
>  /**
> + * Retrieve names of extended statistics of an Ethernet device.
> + *
> + * Names within ptr_strings will be aligned to RTE_ETH_XSTATS_NAME_SIZE
> and
> + * will be listed in ascending mapping order.
> + *
> + * @param port_id
> + *   The port identifier of the Ethernet device.
> + * @param ptr_names
> + *  Block of memory to insert names into. Must be at least limit in size.
> + *  If NULL, function returns how many statistics are available.
> + * @param limit
> + *  Capacity of ptr_strings (number of names). Ignored if ptr_string is
> NULL.
> + * @return
> + *  If successful, number of statistics; negative on error.
> + */
> +int rte_eth_xstats_names(uint8_t port_id, struct rte_eth_xstats_name
> *ptr_names,
> +	unsigned limit);
> +
> +/**
>   * Retrieve extended statistics of an Ethernet device.
>   *
>   * @param port_id
> --
> 2.5.5

Nice work.

Regards,
Dave