[dpdk-dev] [PATCH v6 4/4] testpmd: make use of per-PMD TxRx parameters

[Remy Horton <remy.horton@intel.com>]

The optimal values of several transmission & reception related
parameters, such as burst sizes, descriptor ring sizes, and number
of queues, varies between different network interface devices. This
patch allows testpmd to make use of per-PMD tuned parameter values.

Signed-off-by: Remy Horton <remy.horton@intel.com>
Acked-by: Shreyansh Jain <shreyansh.jain@nxp.com>
---
 app/test-pmd/cmdline.c                | 31 +++++++++++++++++++++++++---
 app/test-pmd/parameters.c             | 38 ++++++++++++++++++++++++++++++-----
 app/test-pmd/testpmd.c                |  5 +++--
 doc/guides/testpmd_app_ug/run_app.rst |  4 +++-
 4 files changed, 67 insertions(+), 11 deletions(-)

diff --git a/app/test-pmd/cmdline.c b/app/test-pmd/cmdline.c
index 40b31ad..0914425 100644
--- a/app/test-pmd/cmdline.c
+++ b/app/test-pmd/cmdline.c
@@ -2599,6 +2599,8 @@ cmd_config_burst_parsed(void *parsed_result,
 			__attribute__((unused)) void *data)
 {
 	struct cmd_config_burst *res = parsed_result;
+	struct rte_eth_dev_info dev_info;
+	uint16_t rec_nb_pkts;
 
 	if (!all_ports_stopped()) {
 		printf("Please stop all ports first\n");
@@ -2606,11 +2608,34 @@ cmd_config_burst_parsed(void *parsed_result,
 	}
 
 	if (!strcmp(res->name, "burst")) {
-		if (res->value < 1 || res->value > MAX_PKT_BURST) {
+		if (res->value == 0) {
+			/* If user gives a value of zero, query the PMD for
+			 * its recommended Rx burst size. Testpmd uses a single
+			 * size for all ports, so assume all ports are the same
+			 * NIC model and use the values from Port 0.
+			 */
+			rte_eth_dev_info_get(0, &dev_info);
+			rec_nb_pkts = dev_info.default_rxportconf.burst_size;
+
+			if (rec_nb_pkts == 0) {
+				printf("PMD does not recommend a burst size.\n"
+					"User provided value must be between"
+					" 1 and %d\n", MAX_PKT_BURST);
+				return;
+			} else if (rec_nb_pkts > MAX_PKT_BURST) {
+				printf("PMD recommended burst size of %d"
+					" exceeds maximum value of %d\n",
+					rec_nb_pkts, MAX_PKT_BURST);
+				return;
+			}
+			printf("Using PMD-provided burst value of %d\n",
+				rec_nb_pkts);
+			nb_pkt_per_burst = rec_nb_pkts;
+		} else if (res->value > MAX_PKT_BURST) {
 			printf("burst must be >= 1 && <= %d\n", MAX_PKT_BURST);
 			return;
-		}
-		nb_pkt_per_burst = res->value;
+		} else
+			nb_pkt_per_burst = res->value;
 	} else {
 		printf("Unknown parameter\n");
 		return;
diff --git a/app/test-pmd/parameters.c b/app/test-pmd/parameters.c
index 2192bdc..cb6a229 100644
--- a/app/test-pmd/parameters.c
+++ b/app/test-pmd/parameters.c
@@ -544,6 +544,8 @@ launch_args_parse(int argc, char** argv)
 	/* Default offloads for all ports. */
 	uint64_t rx_offloads = rx_mode.offloads;
 	uint64_t tx_offloads = tx_mode.offloads;
+	struct rte_eth_dev_info dev_info;
+	uint16_t rec_nb_pkts;
 
 	static struct option lgopts[] = {
 		{ "help",			0, 0, 0 },
@@ -947,12 +949,38 @@ launch_args_parse(int argc, char** argv)
 			}
 			if (!strcmp(lgopts[opt_idx].name, "burst")) {
 				n = atoi(optarg);
-				if ((n >= 1) && (n <= MAX_PKT_BURST))
-					nb_pkt_per_burst = (uint16_t) n;
-				else
+				if (n == 0) {
+					/* A burst size of zero means that the
+					 * PMD should be queried for
+					 * recommended Rx burst size. Since
+					 * testpmd uses a single size for all
+					 * ports, port 0 is queried for the
+					 * value, on the assumption that all
+					 * ports are of the same NIC model.
+					 */
+					rte_eth_dev_info_get(0, &dev_info);
+					rec_nb_pkts = dev_info
+						.default_rxportconf.burst_size;
+
+					if (rec_nb_pkts == 0)
+						rte_exit(EXIT_FAILURE,
+							"PMD does not recommend a burst size. "
+							"Provided value must be between "
+							"1 and %d\n", MAX_PKT_BURST);
+					else if (rec_nb_pkts > MAX_PKT_BURST)
+						rte_exit(EXIT_FAILURE,
+							"PMD recommended burst size of %d"
+							" exceeds maximum value of %d\n",
+							rec_nb_pkts, MAX_PKT_BURST);
+					printf("Using PMD-provided burst value of %d\n",
+						rec_nb_pkts);
+					nb_pkt_per_burst = rec_nb_pkts;
+				} else if (n > MAX_PKT_BURST)
 					rte_exit(EXIT_FAILURE,
-						 "burst must >= 1 and <= %d]",
-						 MAX_PKT_BURST);
+						"burst must be between1 and %d\n",
+						MAX_PKT_BURST);
+				else
+					nb_pkt_per_burst = (uint16_t) n;
 			}
 			if (!strcmp(lgopts[opt_idx].name, "mbcache")) {
 				n = atoi(optarg);
diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c
index 4c0e258..82eb197 100644
--- a/app/test-pmd/testpmd.c
+++ b/app/test-pmd/testpmd.c
@@ -210,9 +210,10 @@ queueid_t nb_txq = 1; /**< Number of TX queues per port. */
 
 /*
  * Configurable number of RX/TX ring descriptors.
+ * Defaults are supplied by drivers via ethdev.
  */
-#define RTE_TEST_RX_DESC_DEFAULT 1024
-#define RTE_TEST_TX_DESC_DEFAULT 1024
+#define RTE_TEST_RX_DESC_DEFAULT 0
+#define RTE_TEST_TX_DESC_DEFAULT 0
 uint16_t nb_rxd = RTE_TEST_RX_DESC_DEFAULT; /**< Number of RX descriptors. */
 uint16_t nb_txd = RTE_TEST_TX_DESC_DEFAULT; /**< Number of TX descriptors. */
 
diff --git a/doc/guides/testpmd_app_ug/run_app.rst b/doc/guides/testpmd_app_ug/run_app.rst
index 1fd5395..f876f95 100644
--- a/doc/guides/testpmd_app_ug/run_app.rst
+++ b/doc/guides/testpmd_app_ug/run_app.rst
@@ -372,7 +372,9 @@ The commandline options are:
 *   ``--burst=N``
 
     Set the number of packets per burst to N, where 1 <= N <= 512.
-    The default value is 16.
+    The default value is 32.
+    If set to 0, driver default is used if defined. Else, if driver
+    default is not defined, default of 32 is used.
 
 *   ``--mbcache=N``
 
-- 
2.9.5