ethdev: get xstats ID by name

Introduced new function: rte_eth_xstats_get_id_by_name
to retrieve xstats ids by its names.

Signed-off-by: Kuba Kozak <kubax.kozak@intel.com>

lib/librte_ether/rte_ethdev.c

@@ -1383,6 +1383,50 @@ get_xstats_count(uint8_t port_id)
 	return count;
 }
 
+int
+rte_eth_xstats_get_id_by_name(uint8_t port_id, const char *xstat_name,
+		uint64_t *id)
+{
+	int cnt_xstats, idx_xstat;
+
+	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
+
+	if (!id) {
+		RTE_PMD_DEBUG_TRACE("Error: id pointer is NULL\n");
+		return -ENOMEM;
+	}
+
+	if (!xstat_name) {
+		RTE_PMD_DEBUG_TRACE("Error: xstat_name pointer is NULL\n");
+		return -ENOMEM;
+	}
+
+	/* Get count */
+	cnt_xstats = rte_eth_xstats_get_names_by_id(port_id, NULL, 0, NULL);
+	if (cnt_xstats  < 0) {
+		RTE_PMD_DEBUG_TRACE("Error: Cannot get count of xstats\n");
+		return -ENODEV;
+	}
+
+	/* Get id-name lookup table */
+	struct rte_eth_xstat_name xstats_names[cnt_xstats];
+
+	if (cnt_xstats != rte_eth_xstats_get_names_by_id(
+			port_id, xstats_names, cnt_xstats, NULL)) {
+		RTE_PMD_DEBUG_TRACE("Error: Cannot get xstats lookup\n");
+		return -1;
+	}
+
+	for (idx_xstat = 0; idx_xstat < cnt_xstats; idx_xstat++) {
+		if (!strcmp(xstats_names[idx_xstat].name, xstat_name)) {
+			*id = idx_xstat;
+			return 0;
+		};
+	}
+
+	return -EINVAL;
+}
+
 int
 rte_eth_xstats_get_names_by_id(uint8_t port_id,
 	struct rte_eth_xstat_name *xstats_names, unsigned int size,

lib/librte_ether/rte_ethdev.h

@@ -2378,6 +2378,26 @@ rte_eth_xstats_get_names_by_id(uint8_t port_id,
 int rte_eth_xstats_get_by_id(uint8_t port_id, const uint64_t *ids,
 			     uint64_t *values, unsigned int n);
 
+/**
+ * Gets the ID of a statistic from its name.
+ *
+ * This function searches for the statistics using string compares, and
+ * as such should not be used on the fast-path. For fast-path retrieval of
+ * specific statistics, store the ID as provided in *id* from this function,
+ * and pass the ID to rte_eth_xstats_get()
+ *
+ * @param port_id The port to look up statistics from
+ * @param xstat_name The name of the statistic to return
+ * @param[out] id A pointer to an app-supplied uint64_t which should be
+ *                set to the ID of the stat if the stat exists.
+ * @return
+ *    0 on success
+ *    -ENODEV for invalid port_id,
+ *    -EINVAL if the xstat_name doesn't exist in port_id
+ */
+int rte_eth_xstats_get_id_by_name(uint8_t port_id, const char *xstat_name,
+		uint64_t *id);
+
 /**
  * Reset extended statistics of an Ethernet device.
  *

lib/librte_ether/rte_ether_version.map

@@ -152,6 +152,7 @@ DPDK_17.05 {
 	rte_eth_dev_attach_secondary;
 	rte_eth_find_next;
 	rte_eth_xstats_get_by_id;
+	rte_eth_xstats_get_id_by_name;
 	rte_eth_xstats_get_names_by_id;
 
 } DPDK_17.02;