[dpdk-dev] [PATCH v6 1/5] ethdev: new xstats API add retrieving by ID

Kuba Kozak kubax.kozak at intel.com
Thu Apr 13 16:59:24 CEST 2017


From: Jacek Piasecki <jacekx.piasecki at intel.com>

Extended xstats API in ethdev library to allow grouping of stats
logically so they can be retrieved per logical grouping  managed
by the application.
Changed existing functions rte_eth_xstats_get_names and
rte_eth_xstats_get to use a new list of arguments: array of ids
and array of values. ABI versioning mechanism was used to
support backward compatibility.
Introduced two new functions rte_eth_xstats_get_all and
rte_eth_xstats_get_names_all which keeps functionality of the
previous ones (respectively rte_eth_xstats_get and
rte_eth_xstats_get_names) but use new API inside.

test-pmd: add support for new xstats API retrieving by id in
testpmd application: xstats_get() and
xstats_get_names() call with modified parameters.

doc: add description for modified xstats API
Documentation change for modified extended statistics API functions.
The old API only allows retrieval of *all* of the NIC statistics
at once. Given this requires a MMIO read PCI transaction per statistic
it is an inefficient way of retrieving just a few key statistics.
Often a monitoring agent only has an interest in a few key statistics,
and the old API forces wasting CPU time and PCIe bandwidth in retrieving
*all* statistics; even those that the application didn't explicitly
show an interest in.
The new, more flexible API allow retrieval of statistics per ID.
If a PMD wishes, it can be implemented to read just the required
NIC registers. As a result, the monitoring application no longer wastes
PCIe bandwidth and CPU time.

Signed-off-by: Jacek Piasecki <jacekx.piasecki at intel.com>
Signed-off-by: Kuba Kozak <kubax.kozak at intel.com>
Signed-off-by: Tomasz Kulasek <tomaszx.kulasek at intel.com>
---
 app/proc_info/main.c                    |   6 +-
 app/test-pmd/config.c                   |  19 +-
 doc/guides/prog_guide/poll_mode_drv.rst | 173 ++++++++++++--
 doc/guides/rel_notes/release_17_05.rst  |   6 +
 lib/librte_ether/rte_ethdev.c           | 386 +++++++++++++++++++++++---------
 lib/librte_ether/rte_ethdev.h           | 144 +++++++++++-
 lib/librte_ether/rte_ether_version.map  |   4 +
 7 files changed, 596 insertions(+), 142 deletions(-)

diff --git a/app/proc_info/main.c b/app/proc_info/main.c
index d576b42..9f5e219 100644
--- a/app/proc_info/main.c
+++ b/app/proc_info/main.c
@@ -358,7 +358,7 @@ static void collectd_resolve_cnt_type(char *cnt_type, size_t cnt_type_len,
 	int len, ret, i;
 	static const char *nic_stats_border = "########################";
 
-	len = rte_eth_xstats_get_names(port_id, NULL, 0);
+	len = rte_eth_xstats_get_names_all(port_id, NULL, 0);
 	if (len < 0) {
 		printf("Cannot get xstats count\n");
 		return;
@@ -375,7 +375,7 @@ static void collectd_resolve_cnt_type(char *cnt_type, size_t cnt_type_len,
 		free(xstats);
 		return;
 	}
-	if (len != rte_eth_xstats_get_names(
+	if (len != rte_eth_xstats_get_names_all(
 			port_id, xstats_names, len)) {
 		printf("Cannot get xstat names\n");
 		goto err;
@@ -385,7 +385,7 @@ static void collectd_resolve_cnt_type(char *cnt_type, size_t cnt_type_len,
 			   port_id);
 	printf("%s############################\n",
 			   nic_stats_border);
-	ret = rte_eth_xstats_get(port_id, xstats, len);
+	ret = rte_eth_xstats_get_all(port_id, xstats, len);
 	if (ret < 0 || ret > len) {
 		printf("Cannot get xstats\n");
 		goto err;
diff --git a/app/test-pmd/config.c b/app/test-pmd/config.c
index 4d873cd..ef07925 100644
--- a/app/test-pmd/config.c
+++ b/app/test-pmd/config.c
@@ -264,9 +264,9 @@ struct rss_type_info {
 void
 nic_xstats_display(portid_t port_id)
 {
-	struct rte_eth_xstat *xstats;
 	int cnt_xstats, idx_xstat;
 	struct rte_eth_xstat_name *xstats_names;
+	uint64_t *values;
 
 	printf("###### NIC extended statistics for port %-2d\n", port_id);
 	if (!rte_eth_dev_is_valid_port(port_id)) {
@@ -275,7 +275,7 @@ struct rss_type_info {
 	}
 
 	/* Get count */
-	cnt_xstats = rte_eth_xstats_get_names(port_id, NULL, 0);
+	cnt_xstats = rte_eth_xstats_get_names(port_id, NULL, 0, NULL);
 	if (cnt_xstats  < 0) {
 		printf("Error: Cannot get count of xstats\n");
 		return;
@@ -288,23 +288,24 @@ struct rss_type_info {
 		return;
 	}
 	if (cnt_xstats != rte_eth_xstats_get_names(
-			port_id, xstats_names, cnt_xstats)) {
+			port_id, xstats_names, cnt_xstats, NULL)) {
 		printf("Error: Cannot get xstats lookup\n");
 		free(xstats_names);
 		return;
 	}
 
 	/* Get stats themselves */
-	xstats = malloc(sizeof(struct rte_eth_xstat) * cnt_xstats);
-	if (xstats == NULL) {
+	values = malloc(sizeof(values) * cnt_xstats);
+	if (values == NULL) {
 		printf("Cannot allocate memory for xstats\n");
 		free(xstats_names);
 		return;
 	}
-	if (cnt_xstats != rte_eth_xstats_get(port_id, xstats, cnt_xstats)) {
+	if (cnt_xstats != rte_eth_xstats_get(port_id, NULL, values,
+			cnt_xstats)) {
 		printf("Error: Unable to get xstats\n");
 		free(xstats_names);
-		free(xstats);
+		free(values);
 		return;
 	}
 
@@ -312,9 +313,9 @@ struct rss_type_info {
 	for (idx_xstat = 0; idx_xstat < cnt_xstats; idx_xstat++)
 		printf("%s: %"PRIu64"\n",
 			xstats_names[idx_xstat].name,
-			xstats[idx_xstat].value);
+			values[idx_xstat]);
 	free(xstats_names);
-	free(xstats);
+	free(values);
 }
 
 void
diff --git a/doc/guides/prog_guide/poll_mode_drv.rst b/doc/guides/prog_guide/poll_mode_drv.rst
index e48c121..a1a758b 100644
--- a/doc/guides/prog_guide/poll_mode_drv.rst
+++ b/doc/guides/prog_guide/poll_mode_drv.rst
@@ -334,24 +334,21 @@ The Ethernet device API exported by the Ethernet PMDs is described in the *DPDK
 Extended Statistics API
 ~~~~~~~~~~~~~~~~~~~~~~~
 
-The extended statistics API allows each individual PMD to expose a unique set
-of statistics. Accessing these from application programs is done via two
-functions:
-
-* ``rte_eth_xstats_get``: Fills in an array of ``struct rte_eth_xstat``
-  with extended statistics.
-* ``rte_eth_xstats_get_names``: Fills in an array of
-  ``struct rte_eth_xstat_name`` with extended statistic name lookup
-  information.
-
-Each ``struct rte_eth_xstat`` contains an identifier and value pair, and
-each ``struct rte_eth_xstat_name`` contains a string. Each identifier
-within the ``struct rte_eth_xstat`` lookup array must have a corresponding
-entry in the ``struct rte_eth_xstat_name`` lookup array. Within the latter
-the index of the entry is the identifier the string is associated with.
-These identifiers, as well as the number of extended statistic exposed, must
-remain constant during runtime. Note that extended statistic identifiers are
+The extended statistics API allows a PMD to expose all statistics that are
+available to it, including statistics that are unique to the device.
+Each statistic has three properties ``name``, ``id`` and ``value``:
+
+* ``name``: A human readable string formatted by the scheme detailed below.
+* ``id``: An integer that represents only that statistic.
+* ``value``: A unsigned 64-bit integer that is the value of the statistic.
+
+Note that extended statistic identifiers are
 driver-specific, and hence might not be the same for different ports.
+The API consists of various ``rte_eth_xstats_*()`` functions, and allows an
+application to be flexible in how it retrieves statistics.
+
+Scheme for Human Readable Names
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 A naming scheme exists for the strings exposed to clients of the API. This is
 to allow scraping of the API for statistics of interest. The naming scheme uses
@@ -363,8 +360,8 @@ strings split by a single underscore ``_``. The scheme is as follows:
 * detail n
 * unit
 
-Examples of common statistics xstats strings, formatted to comply to the scheme
-proposed above:
+Examples of common statistics xstats strings, formatted to comply to the
+above scheme:
 
 * ``rx_bytes``
 * ``rx_crc_errors``
@@ -378,7 +375,7 @@ associated with the receive side of the NIC.  The second component ``packets``
 indicates that the unit of measure is packets.
 
 A more complicated example: ``tx_size_128_to_255_packets``. In this example,
-``tx`` indicates transmission, ``size``  is the first detail, ``128`` etc are
+``tx`` indicates transmission, ``size``  is the first detail, ``128`` etc. are
 more details, and ``packets`` indicates that this is a packet counter.
 
 Some additions in the metadata scheme are as follows:
@@ -392,3 +389,139 @@ Some additions in the metadata scheme are as follows:
 An example where queue numbers are used is as follows: ``tx_q7_bytes`` which
 indicates this statistic applies to queue number 7, and represents the number
 of transmitted bytes on that queue.
+
+API Design
+^^^^^^^^^^
+
+The xstats API uses the ``name``, ``id``, and ``value`` to allow performant
+lookup of specific statistics. Performant lookup means two things;
+
+* No string comparisons with the ``name`` of the statistic in fast-path
+* Allow requesting of only the statistics of interest
+
+The API ensures these requirements are met by mapping the ``name`` of the
+statistic to a unique ``id``, which is used as a key for lookup in the fast-path.
+The API allows applications to request an array of ``id`` values, so that the
+PMD only performs the required calculations. Expected usage is that the
+application scans the ``name`` of each statistic, and caches the ``id``
+if it has an interest in that statistic. On the fast-path, the integer can be used
+to retrieve the actual ``value`` of the statistic that the ``id`` represents.
+
+API Functions
+^^^^^^^^^^^^^
+
+The API is built out of a small number of functions, which can be used to
+retrieve the number of statistics and the names, IDs and values of those
+statistics.
+
+* ``rte_eth_xstats_get_names()``: returns the names of the statistics. When given a
+  ``NULL`` parameter the function returns the number of statistics that are available.
+
+* ``rte_eth_xstats_get_id_by_name()``: Searches for the statistic ID that matches
+  ``xstat_name``. If found, the ``id`` integer is set.
+
+* ``rte_eth_xstats_get()``: Fills in an array of ``uint64_t`` values
+  with matching the provided ``ids`` array. If the ``ids`` array is NULL, it
+  returns all statistics that are available.
+
+
+Application Usage
+^^^^^^^^^^^^^^^^^
+
+Imagine an application that wants to view the dropped packet count. If no
+packets are dropped, the application does not read any other metrics for
+performance reasons. If packets are dropped, the application has a particular
+set of statistics that it requests. This "set" of statistics allows the app to
+decide what next steps to perform. The following code-snippets show how the
+xstats API can be used to achieve this goal.
+
+First step is to get all statistics names and list them:
+
+.. code-block:: c
+
+    struct rte_eth_xstat_name *xstats_names;
+    uint64_t *values;
+    int len, i;
+
+    /* Get number of stats */
+    len = rte_eth_xstats_get_names(port_id, NULL, NULL, 0);
+    if (len < 0) {
+        printf("Cannot get xstats count\n");
+        goto err;
+    }
+
+    xstats_names = malloc(sizeof(struct rte_eth_xstat_name) * len);
+    if (xstats_names == NULL) {
+        printf("Cannot allocate memory for xstat names\n");
+        goto err;
+    }
+
+    /* Retrieve xstats names, passing NULL for IDs to return all statistics */
+    if (len != rte_eth_xstats_get_names(port_id, xstats_names, NULL, len)) {
+        printf("Cannot get xstat names\n");
+        goto err;
+    }
+
+    values = malloc(sizeof(values) * len);
+    if (values == NULL) {
+        printf("Cannot allocate memory for xstats\n");
+        goto err;
+    }
+
+    /* Getting xstats values */
+    if (len != rte_eth_xstats_get(port_id, NULL, values, len)) {
+        printf("Cannot get xstat values\n");
+        goto err;
+    }
+
+    /* Print all xstats names and values */
+    for (i = 0; i < len; i++) {
+        printf("%s: %"PRIu64"\n", xstats_names[i].name, values[i]);
+    }
+
+The application has access to the names of all of the statistics that the PMD
+exposes. The application can decide which statistics are of interest, cache the
+ids of those statistics by looking up the name as follows:
+
+.. code-block:: c
+
+    uint64_t id;
+    uint64_t value;
+    const char *xstat_name = "rx_errors";
+
+    if(!rte_eth_xstats_get_id_by_name(port_id, xstat_name, &id)) {
+        rte_eth_xstats_get(port_id, &id, &value, 1);
+        printf("%s: %"PRIu64"\n", xstat_name, value);
+    }
+    else {
+        printf("Cannot find xstats with a given name\n");
+        goto err;
+    }
+
+The API provides flexibility to the application so that it can look up multiple
+statistics using an array containing multiple ``id`` numbers. This reduces the
+function call overhead of retrieving statistics, and makes lookup of multiple
+statistics simpler for the application.
+
+.. code-block:: c
+
+    #define APP_NUM_STATS 4
+    /* application cached these ids previously; see above */
+    uint64_t ids_array[APP_NUM_STATS] = {3,4,7,21};
+    uint64_t value_array[APP_NUM_STATS];
+
+    /* Getting multiple xstats values from array of IDs */
+    rte_eth_xstats_get(port_id, ids_array, value_array, APP_NUM_STATS);
+
+    uint32_t i;
+    for(i = 0; i < APP_NUM_STATS; i++) {
+        printf("%d: %"PRIu64"\n", ids_array[i], value_array[i]);
+    }
+
+
+This array lookup API for xstats allows the application create multiple
+"groups" of statistics, and look up the values of those IDs using a single API
+call. As an end result, the application is able to achieve its goal of
+monitoring a single statistic ("rx_errors" in this case), and if that shows
+packets being dropped, it can easily retrieve a "set" of statistics using the
+IDs array parameter to ``rte_eth_xstats_get`` function.
diff --git a/doc/guides/rel_notes/release_17_05.rst b/doc/guides/rel_notes/release_17_05.rst
index 4968b8f..5b77226 100644
--- a/doc/guides/rel_notes/release_17_05.rst
+++ b/doc/guides/rel_notes/release_17_05.rst
@@ -416,6 +416,12 @@ API Changes
   * The vhost public header file ``rte_virtio_net.h`` is renamed to
     ``rte_vhost.h``
 
+* **Reworked rte_ethdev library**
+
+  * Changed set of input parameters for ``rte_eth_xstats_get`` and ``rte_eth_xstats_get_names`` functions.
+
+  * Added new functions ``rte_eth_xstats_get_all`` and ``rte_eth_xstats_get_names_all to provide backward compatibility for
+    ``rte_eth_xstats_get`` and ``rte_eth_xstats_get_names``
 
 ABI Changes
 -----------
diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
index 4e1e6dc..0adc1d0 100644
--- a/lib/librte_ether/rte_ethdev.c
+++ b/lib/librte_ether/rte_ethdev.c
@@ -1454,12 +1454,19 @@ struct rte_eth_dev *
 
 	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -EINVAL);
 	dev = &rte_eth_devices[port_id];
+	if (dev->dev_ops->xstats_get_names_by_ids != NULL) {
+		count = (*dev->dev_ops->xstats_get_names_by_ids)(dev, NULL,
+				NULL, 0);
+		if (count < 0)
+			return count;
+	}
 	if (dev->dev_ops->xstats_get_names != NULL) {
 		count = (*dev->dev_ops->xstats_get_names)(dev, NULL, 0);
 		if (count < 0)
 			return count;
 	} else
 		count = 0;
+
 	count += RTE_NB_STATS;
 	count += RTE_MIN(dev->data->nb_rx_queues, RTE_ETHDEV_QUEUE_STAT_CNTRS) *
 		 RTE_NB_RXQ_STATS;
@@ -1469,150 +1476,323 @@ struct rte_eth_dev *
 }
 
 int
-rte_eth_xstats_get_names(uint8_t port_id,
+rte_eth_xstats_get_names_v1607(uint8_t port_id,
 	struct rte_eth_xstat_name *xstats_names,
-	unsigned size)
+	unsigned int size)
 {
-	struct rte_eth_dev *dev;
-	int cnt_used_entries;
-	int cnt_expected_entries;
-	int cnt_driver_entries;
-	uint32_t idx, id_queue;
-	uint16_t num_q;
+	return rte_eth_xstats_get_names(port_id, xstats_names, size, NULL);
+}
+VERSION_SYMBOL(rte_eth_xstats_get_names, _v1607, 16.07);
 
-	cnt_expected_entries = get_xstats_count(port_id);
-	if (xstats_names == NULL || cnt_expected_entries < 0 ||
-			(int)size < cnt_expected_entries)
-		return cnt_expected_entries;
+int
+rte_eth_xstats_get_names_v1705(uint8_t port_id,
+	struct rte_eth_xstat_name *xstats_names, unsigned int size,
+	uint64_t *ids)
+{
+	/* Get all xstats */
+	if (!ids) {
+		struct rte_eth_dev *dev;
+		int cnt_used_entries;
+		int cnt_expected_entries;
+		int cnt_driver_entries;
+		uint32_t idx, id_queue;
+		uint16_t num_q;
 
-	/* port_id checked in get_xstats_count() */
-	dev = &rte_eth_devices[port_id];
-	cnt_used_entries = 0;
+		cnt_expected_entries = get_xstats_count(port_id);
+		if (xstats_names == NULL || cnt_expected_entries < 0 ||
+				(int)size < cnt_expected_entries)
+			return cnt_expected_entries;
 
-	for (idx = 0; idx < RTE_NB_STATS; idx++) {
-		snprintf(xstats_names[cnt_used_entries].name,
-			sizeof(xstats_names[0].name),
-			"%s", rte_stats_strings[idx].name);
-		cnt_used_entries++;
-	}
-	num_q = RTE_MIN(dev->data->nb_rx_queues, RTE_ETHDEV_QUEUE_STAT_CNTRS);
-	for (id_queue = 0; id_queue < num_q; id_queue++) {
-		for (idx = 0; idx < RTE_NB_RXQ_STATS; idx++) {
+		/* port_id checked in get_xstats_count() */
+		dev = &rte_eth_devices[port_id];
+		cnt_used_entries = 0;
+
+		for (idx = 0; idx < RTE_NB_STATS; idx++) {
 			snprintf(xstats_names[cnt_used_entries].name,
 				sizeof(xstats_names[0].name),
-				"rx_q%u%s",
-				id_queue, rte_rxq_stats_strings[idx].name);
+				"%s", rte_stats_strings[idx].name);
 			cnt_used_entries++;
 		}
+		num_q = RTE_MIN(dev->data->nb_rx_queues,
+				RTE_ETHDEV_QUEUE_STAT_CNTRS);
+		for (id_queue = 0; id_queue < num_q; id_queue++) {
+			for (idx = 0; idx < RTE_NB_RXQ_STATS; idx++) {
+				snprintf(xstats_names[cnt_used_entries].name,
+					sizeof(xstats_names[0].name),
+					"rx_q%u%s",
+					id_queue,
+					rte_rxq_stats_strings[idx].name);
+				cnt_used_entries++;
+			}
 
+		}
+		num_q = RTE_MIN(dev->data->nb_tx_queues,
+				RTE_ETHDEV_QUEUE_STAT_CNTRS);
+		for (id_queue = 0; id_queue < num_q; id_queue++) {
+			for (idx = 0; idx < RTE_NB_TXQ_STATS; idx++) {
+				snprintf(xstats_names[cnt_used_entries].name,
+					sizeof(xstats_names[0].name),
+					"tx_q%u%s",
+					id_queue,
+					rte_txq_stats_strings[idx].name);
+				cnt_used_entries++;
+			}
+		}
+
+		if (dev->dev_ops->xstats_get_names_by_ids != NULL) {
+			/* If there are any driver-specific xstats, append them
+			 * to end of list.
+			 */
+			cnt_driver_entries =
+				(*dev->dev_ops->xstats_get_names_by_ids)(
+				dev,
+				xstats_names + cnt_used_entries,
+				NULL,
+				size - cnt_used_entries);
+			if (cnt_driver_entries < 0)
+				return cnt_driver_entries;
+			cnt_used_entries += cnt_driver_entries;
+
+		} else if (dev->dev_ops->xstats_get_names != NULL) {
+			/* If there are any driver-specific xstats, append them
+			 * to end of list.
+			 */
+			cnt_driver_entries = (*dev->dev_ops->xstats_get_names)(
+				dev,
+				xstats_names + cnt_used_entries,
+				size - cnt_used_entries);
+			if (cnt_driver_entries < 0)
+				return cnt_driver_entries;
+			cnt_used_entries += cnt_driver_entries;
+		}
+
+		return cnt_used_entries;
 	}
-	num_q = RTE_MIN(dev->data->nb_tx_queues, RTE_ETHDEV_QUEUE_STAT_CNTRS);
-	for (id_queue = 0; id_queue < num_q; id_queue++) {
-		for (idx = 0; idx < RTE_NB_TXQ_STATS; idx++) {
-			snprintf(xstats_names[cnt_used_entries].name,
-				sizeof(xstats_names[0].name),
-				"tx_q%u%s",
-				id_queue, rte_txq_stats_strings[idx].name);
-			cnt_used_entries++;
+	/* Get only xstats given by IDS */
+	else {
+		uint16_t len, i;
+		struct rte_eth_xstat_name *xstats_names_copy;
+
+		len = rte_eth_xstats_get_names_v1705(port_id, NULL, 0, NULL);
+
+		xstats_names_copy =
+				malloc(sizeof(struct rte_eth_xstat_name) * len);
+		if (!xstats_names_copy) {
+			RTE_PMD_DEBUG_TRACE(
+			     "ERROR: can't allocate memory for values_copy\n");
+			free(xstats_names_copy);
+			return -1;
+		}
+
+		rte_eth_xstats_get_names_v1705(port_id, xstats_names_copy,
+				len, NULL);
+
+		for (i = 0; i < size; i++) {
+			if (ids[i] >= len) {
+				RTE_PMD_DEBUG_TRACE(
+					"ERROR: id value isn't valid\n");
+				return -1;
+			}
+			strcpy(xstats_names[i].name,
+					xstats_names_copy[ids[i]].name);
 		}
+		free(xstats_names_copy);
+		return size;
 	}
+}
+BIND_DEFAULT_SYMBOL(rte_eth_xstats_get_names, _v1705, 17.05);
 
-	if (dev->dev_ops->xstats_get_names != NULL) {
-		/* If there are any driver-specific xstats, append them
-		 * to end of list.
-		 */
-		cnt_driver_entries = (*dev->dev_ops->xstats_get_names)(
-			dev,
-			xstats_names + cnt_used_entries,
-			size - cnt_used_entries);
-		if (cnt_driver_entries < 0)
-			return cnt_driver_entries;
-		cnt_used_entries += cnt_driver_entries;
+MAP_STATIC_SYMBOL(int
+		rte_eth_xstats_get_names(uint8_t port_id,
+			struct rte_eth_xstat_name *xstats_names,
+			unsigned int size,
+			uint64_t *ids), rte_eth_xstats_get_names_v1705);
+
+/* retrieve ethdev extended statistics */
+int
+rte_eth_xstats_get_v22(uint8_t port_id, struct rte_eth_xstat *xstats,
+	unsigned int n)
+{
+	uint64_t *values_copy;
+	uint16_t size, i;
+
+	values_copy = malloc(sizeof(values_copy) * n);
+	if (!values_copy) {
+		RTE_PMD_DEBUG_TRACE(
+				"ERROR: Cannot allocate memory for xstats\n");
+		return -1;
 	}
+	size = rte_eth_xstats_get(port_id, 0, values_copy, n);
 
-	return cnt_used_entries;
+	for (i = 0; i < n; i++) {
+		xstats[i].id = i;
+		xstats[i].value = values_copy[i];
+	}
+	free(values_copy);
+	return size;
 }
+VERSION_SYMBOL(rte_eth_xstats_get, _v22, 2.2);
 
 /* retrieve ethdev extended statistics */
 int
-rte_eth_xstats_get(uint8_t port_id, struct rte_eth_xstat *xstats,
-	unsigned n)
+rte_eth_xstats_get_v1705(uint8_t port_id, uint64_t *ids, uint64_t *values,
+	unsigned int n)
 {
-	struct rte_eth_stats eth_stats;
-	struct rte_eth_dev *dev;
-	unsigned count = 0, i, q;
-	signed xcount = 0;
-	uint64_t val, *stats_ptr;
-	uint16_t nb_rxqs, nb_txqs;
+	/* If need all xstats */
+	if (!ids) {
+		struct rte_eth_stats eth_stats;
+		struct rte_eth_dev *dev;
+		unsigned int count = 0, i, q;
+		signed int xcount = 0;
+		uint64_t val, *stats_ptr;
+		uint16_t nb_rxqs, nb_txqs;
 
-	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -EINVAL);
+		RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
+		dev = &rte_eth_devices[port_id];
 
-	dev = &rte_eth_devices[port_id];
+		nb_rxqs = RTE_MIN(dev->data->nb_rx_queues,
+				RTE_ETHDEV_QUEUE_STAT_CNTRS);
+		nb_txqs = RTE_MIN(dev->data->nb_tx_queues,
+				RTE_ETHDEV_QUEUE_STAT_CNTRS);
 
-	nb_rxqs = RTE_MIN(dev->data->nb_rx_queues, RTE_ETHDEV_QUEUE_STAT_CNTRS);
-	nb_txqs = RTE_MIN(dev->data->nb_tx_queues, RTE_ETHDEV_QUEUE_STAT_CNTRS);
+		/* Return generic statistics */
+		count = RTE_NB_STATS + (nb_rxqs * RTE_NB_RXQ_STATS) +
+			(nb_txqs * RTE_NB_TXQ_STATS);
 
-	/* Return generic statistics */
-	count = RTE_NB_STATS + (nb_rxqs * RTE_NB_RXQ_STATS) +
-		(nb_txqs * RTE_NB_TXQ_STATS);
 
-	/* implemented by the driver */
-	if (dev->dev_ops->xstats_get != NULL) {
-		/* Retrieve the xstats from the driver at the end of the
-		 * xstats struct.
-		 */
-		xcount = (*dev->dev_ops->xstats_get)(dev,
-				     xstats ? xstats + count : NULL,
-				     (n > count) ? n - count : 0);
+		/* implemented by the driver */
+		if (dev->dev_ops->xstats_get_by_ids != NULL) {
+			/* Retrieve the xstats from the driver at the end of the
+			 * xstats struct. Retrieve all xstats.
+			 */
+			xcount = (*dev->dev_ops->xstats_get_by_ids)(dev,
+					NULL,
+					values ? values + count : NULL,
+					(n > count) ? n - count : 0);
+
+			if (xcount < 0)
+				return xcount;
+		/* implemented by the driver */
+		} else if (dev->dev_ops->xstats_get != NULL) {
+			/* Retrieve the xstats from the driver at the end of the
+			 * xstats struct. Retrieve all xstats.
+			 * Compatibility for PMD without xstats_get_by_ids
+			 */
+			unsigned int size = (n > count) ? n - count : 1;
+			struct rte_eth_xstat xstats[size];
 
-		if (xcount < 0)
-			return xcount;
-	}
+			xcount = (*dev->dev_ops->xstats_get)(dev,
+					values ? xstats : NULL,	size);
 
-	if (n < count + xcount || xstats == NULL)
-		return count + xcount;
+			if (xcount < 0)
+				return xcount;
 
-	/* now fill the xstats structure */
-	count = 0;
-	rte_eth_stats_get(port_id, &eth_stats);
+			if (values != NULL)
+				for (i = 0 ; i < (unsigned int)xcount; i++)
+					values[i + count] = xstats[i].value;
+		}
 
-	/* global stats */
-	for (i = 0; i < RTE_NB_STATS; i++) {
-		stats_ptr = RTE_PTR_ADD(&eth_stats,
-					rte_stats_strings[i].offset);
-		val = *stats_ptr;
-		xstats[count++].value = val;
-	}
+		if (n < count + xcount || values == NULL)
+			return count + xcount;
 
-	/* per-rxq stats */
-	for (q = 0; q < nb_rxqs; q++) {
-		for (i = 0; i < RTE_NB_RXQ_STATS; i++) {
+		/* now fill the xstats structure */
+		count = 0;
+		rte_eth_stats_get(port_id, &eth_stats);
+
+		/* global stats */
+		for (i = 0; i < RTE_NB_STATS; i++) {
 			stats_ptr = RTE_PTR_ADD(&eth_stats,
-					rte_rxq_stats_strings[i].offset +
-					q * sizeof(uint64_t));
+						rte_stats_strings[i].offset);
 			val = *stats_ptr;
-			xstats[count++].value = val;
+			values[count++] = val;
+		}
+
+		/* per-rxq stats */
+		for (q = 0; q < nb_rxqs; q++) {
+			for (i = 0; i < RTE_NB_RXQ_STATS; i++) {
+				stats_ptr = RTE_PTR_ADD(&eth_stats,
+					    rte_rxq_stats_strings[i].offset +
+					    q * sizeof(uint64_t));
+				val = *stats_ptr;
+				values[count++] = val;
+			}
+		}
+
+		/* per-txq stats */
+		for (q = 0; q < nb_txqs; q++) {
+			for (i = 0; i < RTE_NB_TXQ_STATS; i++) {
+				stats_ptr = RTE_PTR_ADD(&eth_stats,
+					    rte_txq_stats_strings[i].offset +
+					    q * sizeof(uint64_t));
+				val = *stats_ptr;
+				values[count++] = val;
+			}
 		}
+
+		return count + xcount;
 	}
+	/* Need only xstats given by IDS array */
+	else {
+		uint16_t i, size;
+		uint64_t *values_copy;
 
-	/* per-txq stats */
-	for (q = 0; q < nb_txqs; q++) {
-		for (i = 0; i < RTE_NB_TXQ_STATS; i++) {
-			stats_ptr = RTE_PTR_ADD(&eth_stats,
-					rte_txq_stats_strings[i].offset +
-					q * sizeof(uint64_t));
-			val = *stats_ptr;
-			xstats[count++].value = val;
+		size = rte_eth_xstats_get_v1705(port_id, NULL, NULL, 0);
+
+		values_copy = malloc(sizeof(values_copy) * size);
+		if (!values_copy) {
+			RTE_PMD_DEBUG_TRACE(
+			    "ERROR: can't allocate memory for values_copy\n");
+			return -1;
+		}
+
+		rte_eth_xstats_get_v1705(port_id, NULL, values_copy, size);
+
+		for (i = 0; i < n; i++) {
+			if (ids[i] >= size) {
+				RTE_PMD_DEBUG_TRACE(
+					"ERROR: id value isn't valid\n");
+				return -1;
+			}
+			values[i] = values_copy[ids[i]];
 		}
+		free(values_copy);
+		return n;
+	}
+}
+BIND_DEFAULT_SYMBOL(rte_eth_xstats_get, _v1705, 17.05);
+
+MAP_STATIC_SYMBOL(int
+		rte_eth_xstats_get(uint8_t port_id, uint64_t *ids,
+		uint64_t *values, unsigned int n), rte_eth_xstats_get_v1705);
+
+int
+rte_eth_xstats_get_all(uint8_t port_id, struct rte_eth_xstat *xstats,
+	unsigned int n)
+{
+	uint64_t *values_copy;
+	uint16_t size, i;
+
+	values_copy = malloc(sizeof(values_copy) * n);
+	if (!values_copy) {
+		RTE_PMD_DEBUG_TRACE(
+				"ERROR: Cannot allocate memory for xstats\n");
+		return -1;
 	}
+	size = rte_eth_xstats_get(port_id, 0, values_copy, n);
 
-	for (i = 0; i < count; i++)
+	for (i = 0; i < n; i++) {
 		xstats[i].id = i;
-	/* add an offset to driver-specific stats */
-	for ( ; i < count + xcount; i++)
-		xstats[i].id += count;
+		xstats[i].value = values_copy[i];
+	}
+	free(values_copy);
+	return size;
+}
 
-	return count + xcount;
+int
+rte_eth_xstats_get_names_all(uint8_t port_id,
+		struct rte_eth_xstat_name *xstats_names, unsigned int n)
+{
+	return rte_eth_xstats_get_names(port_id, xstats_names, n, NULL);
 }
 
 /* reset ethdev extended statistics */
diff --git a/lib/librte_ether/rte_ethdev.h b/lib/librte_ether/rte_ethdev.h
index d072538..8c94b88 100644
--- a/lib/librte_ether/rte_ethdev.h
+++ b/lib/librte_ether/rte_ethdev.h
@@ -186,6 +186,7 @@
 #include "rte_ether.h"
 #include "rte_eth_ctrl.h"
 #include "rte_dev_info.h"
+#include "rte_compat.h"
 
 struct rte_mbuf;
 
@@ -1118,6 +1119,10 @@ typedef int (*eth_xstats_get_t)(struct rte_eth_dev *dev,
 	struct rte_eth_xstat *stats, unsigned n);
 /**< @internal Get extended stats of an Ethernet device. */
 
+typedef int (*eth_xstats_get_by_ids_t)(struct rte_eth_dev *dev,
+		uint64_t *ids, uint64_t *values, unsigned int n);
+/**< @internal Get extended stats of an Ethernet device. */
+
 typedef void (*eth_xstats_reset_t)(struct rte_eth_dev *dev);
 /**< @internal Reset extended stats of an Ethernet device. */
 
@@ -1125,6 +1130,17 @@ typedef int (*eth_xstats_get_names_t)(struct rte_eth_dev *dev,
 	struct rte_eth_xstat_name *xstats_names, unsigned size);
 /**< @internal Get names of extended stats of an Ethernet device. */
 
+typedef int (*eth_xstats_get_names_by_ids_t)(struct rte_eth_dev *dev,
+	struct rte_eth_xstat_name *xstats_names, uint64_t *ids,
+	unsigned int size);
+/**< @internal Get names of extended stats of an Ethernet device. */
+
+typedef int (*eth_xstats_get_by_name_t)(struct rte_eth_dev *dev,
+		struct rte_eth_xstat_name *xstats_names,
+		struct rte_eth_xstat *xstat,
+		const char *name);
+/**< @internal Get xstat specified by name 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,
@@ -1563,6 +1579,12 @@ struct eth_dev_ops {
 	eth_timesync_adjust_time   timesync_adjust_time; /** Adjust the device clock. */
 	eth_timesync_read_time     timesync_read_time; /** Get the device clock time. */
 	eth_timesync_write_time    timesync_write_time; /** Set the device clock time. */
+	eth_xstats_get_by_ids_t    xstats_get_by_ids;
+	/**< Get extended device statistics by ID. */
+	eth_xstats_get_names_by_ids_t xstats_get_names_by_ids;
+	/**< Get name of extended device statistics by ID. */
+	eth_xstats_get_by_name_t   xstats_get_by_name;
+	/**< Get extended device statistics by name. */
 };
 
 /**
@@ -2325,7 +2347,32 @@ int rte_eth_tx_queue_setup(uint8_t port_id, uint16_t tx_queue_id,
 void rte_eth_stats_reset(uint8_t port_id);
 
 /**
- * Retrieve names of extended statistics of an Ethernet device.
+ * Retrieve all extended statistics of an Ethernet device.
+ *
+ * @param port_id
+ *   The port identifier of the Ethernet device.
+ * @param xstats
+ *   A pointer to a table of structure of type *rte_eth_xstat*
+ *   to be filled with device statistics ids and values: id is the
+ *   index of the name string in xstats_names (see rte_eth_xstats_get_names()),
+ *   and value is the statistic counter.
+ *   This parameter can be set to NULL if n is 0.
+ * @param n
+ *   The size of the xstats array (number of elements).
+ * @return
+ *   - A positive value lower or equal to n: success. The return value
+ *     is the number of entries filled in the stats table.
+ *   - A positive value higher than n: error, the given statistics table
+ *     is too small. The return value corresponds to the size that should
+ *     be given to succeed. The entries in the table are not valid and
+ *     shall not be used by the caller.
+ *   - A negative value on error (invalid port id).
+ */
+int rte_eth_xstats_get_all(uint8_t port_id, struct rte_eth_xstat *xstats,
+	unsigned int n);
+
+/**
+ * Retrieve names of all extended statistics of an Ethernet device.
  *
  * @param port_id
  *   The port identifier of the Ethernet device.
@@ -2333,7 +2380,7 @@ int rte_eth_tx_queue_setup(uint8_t port_id, uint16_t tx_queue_id,
  *   An rte_eth_xstat_name array of at least *size* elements to
  *   be filled. If set to NULL, the function returns the required number
  *   of elements.
- * @param size
+ * @param n
  *   The size of the xstats_names array (number of elements).
  * @return
  *   - A positive value lower or equal to size: success. The return value
@@ -2344,9 +2391,8 @@ int rte_eth_tx_queue_setup(uint8_t port_id, uint16_t tx_queue_id,
  *     shall not be used by the caller.
  *   - A negative value on error (invalid port id).
  */
-int rte_eth_xstats_get_names(uint8_t port_id,
-		struct rte_eth_xstat_name *xstats_names,
-		unsigned size);
+int rte_eth_xstats_get_names_all(uint8_t port_id,
+		struct rte_eth_xstat_name *xstats_names, unsigned int n);
 
 /**
  * Retrieve extended statistics of an Ethernet device.
@@ -2370,8 +2416,92 @@ int rte_eth_xstats_get_names(uint8_t port_id,
  *     shall not be used by the caller.
  *   - A negative value on error (invalid port id).
  */
-int rte_eth_xstats_get(uint8_t port_id, struct rte_eth_xstat *xstats,
-		unsigned n);
+int rte_eth_xstats_get_v22(uint8_t port_id, struct rte_eth_xstat *xstats,
+	unsigned int n);
+
+/**
+ * Retrieve extended statistics of an Ethernet device.
+ *
+ * @param port_id
+ *   The port identifier of the Ethernet device.
+ * @param ids
+ *   A pointer to an ids array passed by application. This tells wich
+ *   statistics values function should retrieve. This parameter
+ *   can be set to NULL if n is 0. In this case function will retrieve
+ *   all avalible statistics.
+ * @param values
+ *   A pointer to a table to be filled with device statistics values.
+ * @param n
+ *   The size of the ids array (number of elements).
+ * @return
+ *   - A positive value lower or equal to n: success. The return value
+ *     is the number of entries filled in the stats table.
+ *   - A positive value higher than n: error, the given statistics table
+ *     is too small. The return value corresponds to the size that should
+ *     be given to succeed. The entries in the table are not valid and
+ *     shall not be used by the caller.
+ *   - A negative value on error (invalid port id).
+ */
+int rte_eth_xstats_get_v1705(uint8_t port_id, uint64_t *ids, uint64_t *values,
+	unsigned int n);
+
+int rte_eth_xstats_get(uint8_t port_id, uint64_t *ids, uint64_t *values,
+	unsigned int n);
+
+/**
+ * Retrieve extended statistics of an Ethernet device.
+ *
+ * @param port_id
+ *   The port identifier of the Ethernet device.
+ * @param xstats_names
+ *   A pointer to a table of structure of type *rte_eth_xstat*
+ *   to be filled with device statistics ids and values: id is the
+ *   index of the name string in xstats_names (see rte_eth_xstats_get_names()),
+ *   and value is the statistic counter.
+ *   This parameter can be set to NULL if n is 0.
+ * @param n
+ *   The size of the xstats array (number of elements).
+ * @return
+ *   - A positive value lower or equal to n: success. The return value
+ *     is the number of entries filled in the stats table.
+ *   - A positive value higher than n: error, the given statistics table
+ *     is too small. The return value corresponds to the size that should
+ *     be given to succeed. The entries in the table are not valid and
+ *     shall not be used by the caller.
+ *   - A negative value on error (invalid port id).
+ */
+int rte_eth_xstats_get_names_v1607(uint8_t port_id,
+		struct rte_eth_xstat_name *xstats_names, unsigned int n);
+
+/**
+ * Retrieve names of extended statistics of an Ethernet device.
+ *
+ * @param port_id
+ *   The port identifier of the Ethernet device.
+ * @param xstats_names
+ *   An rte_eth_xstat_name array of at least *size* elements to
+ *   be filled. If set to NULL, the function returns the required number
+ *   of elements.
+ * @param ids
+ *   IDs array given by app to retrieve specific statistics
+ * @param size
+ *   The size of the xstats_names array (number of elements).
+ * @return
+ *   - A positive value lower or equal to size: success. The return value
+ *     is the number of entries filled in the stats table.
+ *   - A positive value higher than size: error, the given statistics table
+ *     is too small. The return value corresponds to the size that should
+ *     be given to succeed. The entries in the table are not valid and
+ *     shall not be used by the caller.
+ *   - A negative value on error (invalid port id).
+ */
+int rte_eth_xstats_get_names_v1705(uint8_t port_id,
+	struct rte_eth_xstat_name *xstats_names, unsigned int size,
+	uint64_t *ids);
+
+int rte_eth_xstats_get_names(uint8_t port_id,
+	struct rte_eth_xstat_name *xstats_names, unsigned int size,
+	uint64_t *ids);
 
 /**
  * Reset extended statistics of an Ethernet device.
diff --git a/lib/librte_ether/rte_ether_version.map b/lib/librte_ether/rte_ether_version.map
index 0ea3856..a404434 100644
--- a/lib/librte_ether/rte_ether_version.map
+++ b/lib/librte_ether/rte_ether_version.map
@@ -159,5 +159,9 @@ DPDK_17.05 {
 	global:
 
 	rte_eth_find_next;
+	rte_eth_xstats_get;
+	rte_eth_xstats_get_all;
+	rte_eth_xstats_get_names;
+	rte_eth_xstats_get_names_all;
 
 } DPDK_17.02;
-- 
1.9.1



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