[dpdk-dev,v2] app/testpmd: print statistics periodically

diff --git a/app/test-pmd/parameters.c b/app/test-pmd/parameters.c
index fbe6284..230ca2c 100644
--- a/app/test-pmd/parameters.c
+++ b/app/test-pmd/parameters.c
@@ -88,7 +88,7 @@  usage(char* progname)
 	       "[--interactive|-i] "
 	       "[--cmdline-file=FILENAME] "
 #endif
-	       "[--help|-h] | [--auto-start|-a] | ["
+	       "[--help|-h] | [--auto-start|-a] | [-T PERIOD] ["
 	       "--coremask=COREMASK --portmask=PORTMASK --numa "
 	       "--mbuf-size= | --total-num-mbufs= | "
 	       "--nb-cores= | --nb-ports= | "
@@ -109,6 +109,8 @@  usage(char* progname)
 	printf("  --auto-start: start forwarding on init "
 	       "[always when non-interactive].\n");
 	printf("  --help: display this message and quit.\n");
+	printf("  -T PERIOD: statistics will be shown every PERIOD seconds "
+	       "(only if interactive is disabled).\n");
 	printf("  --nb-cores=N: set the number of forwarding cores "
 	       "(1 <= N <= %d).\n", nb_lcores);
 	printf("  --nb-ports=N: set the number of forwarding ports "
@@ -639,7 +641,7 @@  launch_args_parse(int argc, char** argv)
 #else
 #define SHORTOPTS ""
 #endif
-	while ((opt = getopt_long(argc, argvopt, SHORTOPTS "ah",
+	while ((opt = getopt_long(argc, argvopt, SHORTOPTS "ahT:",
 				 lgopts, &opt_idx)) != EOF) {
 		switch (opt) {
 #ifdef RTE_LIBRTE_CMDLINE
@@ -653,6 +655,19 @@  launch_args_parse(int argc, char** argv)
 			auto_start = 1;
 			break;
 
+		case 'T':
+		{
+			char *end = NULL;
+			unsigned int n;
+
+			n = strtoul(optarg, &end, 10);
+			if ((optarg[0] == '\0') || (end == NULL) ||
+					(*end != '\0'))
+				break;
+
+			stats_period = n;
+			break;
+		}
 		case 0: /*long options */
 			if (!strcmp(lgopts[opt_idx].name, "help")) {
 				usage(argv[0]);
diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c
index d1041af..2ab783d 100644
--- a/app/test-pmd/testpmd.c
+++ b/app/test-pmd/testpmd.c
@@ -177,7 +177,7 @@  uint32_t burst_tx_retry_num = BURST_TX_RETRIES;
 uint16_t mbuf_data_size = DEFAULT_MBUF_DATA_SIZE; /**< Mbuf data space size. */
 uint32_t param_total_num_mbufs = 0;  /**< number of mbufs in all pools - if
                                       * specified on command-line. */
-
+uint16_t stats_period; /**< Period to show statistics (disabled by default) */
 /*
  * Configuration of packet segments used by the "txonly" processing engine.
  */
@@ -2229,6 +2229,21 @@  force_quit(void)
 }
 
 static void
+print_stats(void)
+{
+	uint8_t i;
+	const char clr[] = { 27, '[', '2', 'J', '\0' };
+	const char topLeft[] = { 27, '[', '1', ';', '1', 'H', '\0' };
+
+	/* Clear screen and move to top left */
+	printf("%s%s", clr, topLeft);
+
+	printf("\nPort statistics ====================================");
+	for (i = 0; i < cur_fwd_config.nb_fwd_ports; i++)
+		nic_stats_display(fwd_ports_ids[i]);
+}
+
+static void
 signal_handler(int signum)
 {
 	if (signum == SIGINT || signum == SIGTERM) {
@@ -2351,8 +2366,31 @@  main(int argc, char** argv)
 
 		printf("No commandline core given, start packet forwarding\n");
 		start_packet_forwarding(0);
+		if (stats_period != 0) {
+			uint64_t prev_tsc = 0, cur_tsc, timer_tsc = 0;
+			uint64_t timer_period;
+
+			/* Convert to number of cycles */
+			timer_period = stats_period * rte_get_timer_hz();
+
+			while (1) {
+				cur_tsc = rte_rdtsc();
+				timer_tsc += cur_tsc - prev_tsc;
+
+				if (timer_tsc >= timer_period) {
+					print_stats();
+					/* Reset the timer */
+					timer_tsc = 0;
+				}
+				/* Sleep to avoid unnecessary checks */
+				sleep(1);
+				prev_tsc = cur_tsc;
+			}
+		}
+
 		printf("Press enter to exit\n");
 		rc = read(0, &c, 1);
+
 		pmd_test_exit();
 		if (rc < 0)
 			return 1;
diff --git a/app/test-pmd/testpmd.h b/app/test-pmd/testpmd.h
index e6c43ba..8de3379 100644
--- a/app/test-pmd/testpmd.h
+++ b/app/test-pmd/testpmd.h
@@ -378,6 +378,7 @@  extern enum dcb_queue_mapping_mode dcb_q_mapping;
 extern uint16_t mbuf_data_size; /**< Mbuf data space size. */
 extern uint32_t param_total_num_mbufs;
 
+extern uint16_t stats_period;
 
 #ifdef RTE_LIBRTE_LATENCY_STATS
 extern uint8_t latencystats_enabled;
diff --git a/doc/guides/testpmd_app_ug/run_app.rst b/doc/guides/testpmd_app_ug/run_app.rst
index 2a43214..bebe46a 100644
--- a/doc/guides/testpmd_app_ug/run_app.rst
+++ b/doc/guides/testpmd_app_ug/run_app.rst
@@ -188,6 +188,11 @@  The commandline options are:
 
     Start forwarding on initialization.
 
+*   ``-T PERIOD``
+
+    Display statistics every PERIOD seconds, if interactive mode is disabled.
+    The default value is 0, which means that the statistics will not be displayed.
+
 *   ``--nb-cores=N``
 
     Set the number of forwarding cores,