[dpdk-dev] [PATCH v4] examples/l3fwd-power: add telemetry mode support

[Reshma Pattan <reshma.pattan@intel.com>]

Add new telemetry mode support for l3fwd-power.
This is a standalone mode, in this mode l3fwd-power
does simple l3fwding along with calculating
empty polls, full polls, and busy percentage for
each forwarding core. The aggregation of these
values of all cores is reported as application
level telemetry to metric library for every 500ms from the
master core.

The busy percentage is calculated by recording the poll_count
and when the count reaches a defined value the total
cycles it took is measured and compared with minimum and maximum
reference cycles and busy rate is set according to either 0% or
50% or 100%.

Signed-off-by: Reshma Pattan <reshma.pattan@intel.com>
Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>
---
v4: Add -lm dependency to fix shared library linking issue.
rebased release notes.

v3: Update commit message.
Update guide l3_forward_power_man.rst.
Update code to not allow master core in --conf(port,queue,lcore) option for telemetry mode.

v2:Increased telemetry timer value.
Corrected typos.
Fixed if condition to avoid extra indentation.
Added metrics dependency to meson build file.
---
 doc/guides/rel_notes/release_19_08.rst        |   4 +
 .../sample_app_ug/l3_forward_power_man.rst    |  28 ++
 examples/l3fwd-power/Makefile                 |   1 +
 examples/l3fwd-power/main.c                   | 315 ++++++++++++++++--
 examples/l3fwd-power/meson.build              |   2 +-
 5 files changed, 330 insertions(+), 20 deletions(-)

diff --git a/doc/guides/rel_notes/release_19_08.rst b/doc/guides/rel_notes/release_19_08.rst
index 3da266705..d412be654 100644
--- a/doc/guides/rel_notes/release_19_08.rst
+++ b/doc/guides/rel_notes/release_19_08.rst
@@ -99,6 +99,10 @@ New Features
   Updated ``librte_telemetry`` to fetch the global metrics from the
   ``librte_metrics`` library.
 
+* **Added new telemetry mode for l3fwd-power application.**
+
+  Added telemetry mode to l3fwd-power application to report
+  application level busyness, empty and full polls of rte_eth_rx_burst().
 
 Removed Items
 -------------
diff --git a/doc/guides/sample_app_ug/l3_forward_power_man.rst b/doc/guides/sample_app_ug/l3_forward_power_man.rst
index e44a11b2c..6ec24f4ad 100644
--- a/doc/guides/sample_app_ug/l3_forward_power_man.rst
+++ b/doc/guides/sample_app_ug/l3_forward_power_man.rst
@@ -107,6 +107,8 @@ where,
 
 *   --empty-poll: Traffic Aware power management. See below for details
 
+*   --telemetry:  Telemetry mode.
+
 See :doc:`l3_forward` for details.
 The L3fwd-power example reuses the L3fwd command line options.
 
@@ -431,3 +433,29 @@ then be started without the training mode so traffic can start immediately.
 .. code-block:: console
 
         ./examples/l3fwd-power/build/l3fwd-power -l 1-3 -- -p 0x0f --config="(0,0,2),(0,1,3)" --empty-poll "0,340000,540000" –P
+
+Telemetry Mode
+--------------
+
+The telemetry mode support for ``l3fwd-power`` is a standalone mode, in this mode
+``l3fwd-power`` does simple l3fwding along with calculating empty polls, full polls,
+and busy percentage for each forwarding core. The aggregation of these
+values of all cores is reported as application level telemetry to metric
+library for every 500ms from the master core.
+
+The busy percentage is calculated by recording the poll_count
+and when the count reaches a defined value the total
+cycles it took is measured and compared with minimum and maximum
+reference cycles and accordingly busy rate is set  to either 0% or
+50% or 100%.
+
+   .. Note::
+
+      * The CONFIG_RTE_LIBRTE_TELEMETRY should be set in order to get the stats in DPDK telemetry.
+
+.. code-block:: console
+
+        ./examples/l3fwd-power/build/l3fwd-power --telemetry -l 1-3 -- -p 0x0f --config="(0,0,2),(0,1,3)" --telemetry
+
+The new stats ``empty_poll`` , ``full_poll`` and ``busy_percent`` can be viewed by running the script
+``/usertools/dpdk-telemetry-client.py`` and selecting the menu option ``Send for global Metrics``.
diff --git a/examples/l3fwd-power/Makefile b/examples/l3fwd-power/Makefile
index 8a4eee8ae..2b749d5c3 100644
--- a/examples/l3fwd-power/Makefile
+++ b/examples/l3fwd-power/Makefile
@@ -59,6 +59,7 @@ else
 CFLAGS += -DALLOW_EXPERIMENTAL_API
 CFLAGS += -O3
 CFLAGS += $(WERROR_FLAGS)
+LDLIBS += -lm
 
 # workaround for a gcc bug with noreturn attribute
 # http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12603
diff --git a/examples/l3fwd-power/main.c b/examples/l3fwd-power/main.c
index 66ad10507..fb2a9d62f 100644
--- a/examples/l3fwd-power/main.c
+++ b/examples/l3fwd-power/main.c
@@ -14,6 +14,7 @@
 #include <getopt.h>
 #include <unistd.h>
 #include <signal.h>
+#include <math.h>
 
 #include <rte_common.h>
 #include <rte_byteorder.h>
@@ -44,6 +45,7 @@
 #include <rte_power.h>
 #include <rte_spinlock.h>
 #include <rte_power_empty_poll.h>
+#include <rte_metrics.h>
 
 #include "perf_core.h"
 #include "main.h"
@@ -146,17 +148,59 @@ static uint32_t enabled_port_mask = 0;
 static int promiscuous_on = 0;
 /* NUMA is enabled by default. */
 static int numa_on = 1;
-/* emptypoll is disabled by default. */
-static bool empty_poll_on;
+static bool empty_poll_stop;
 static bool empty_poll_train;
-volatile bool empty_poll_stop;
+volatile bool quit_signal;
 static struct  ep_params *ep_params;
 static struct  ep_policy policy;
 static long  ep_med_edpi, ep_hgh_edpi;
+/* timer to update telemetry every 500ms */
+static struct rte_timer telemetry_timer;
+
+/* stats index returned by metrics lib */
+int telstats_index;
+
+struct telstats_name {
+	char name[RTE_ETH_XSTATS_NAME_SIZE];
+};
+
+/* telemetry stats to be reported */
+const struct telstats_name telstats_strings[] = {
+	{"empty_poll"},
+	{"full_poll"},
+	{"busy_percent"}
+};
+
+/* core busyness in percentage */
+enum busy_rate {
+	ZERO = 0,
+	PARTIAL = 50,
+	FULL = 100
+};
+
+/* reference poll count to measure core busyness */
+#define DEFAULT_COUNT 10000
+/*
+ * reference CYCLES to be used to
+ * measure core busyness based on poll count
+ */
+#define MIN_CYCLES 1500000ULL
+#define MAX_CYCLES 2500000ULL
+
+/* (500ms) */
+#define TELEMETRY_INTERVALS_PER_SEC 2
 
 static int parse_ptype; /**< Parse packet type using rx callback, and */
 			/**< disabled by default */
 
+enum appmode {
+	APP_MODE_LEGACY = 0,
+	APP_MODE_EMPTY_POLL,
+	APP_MODE_TELEMETRY
+};
+
+enum appmode app_mode;
+
 enum freq_scale_hint_t
 {
 	FREQ_LOWER    =      -1,
@@ -341,7 +385,26 @@ struct lcore_stats {
 	uint64_t nb_rx_processed;
 	/* total iterations looped recently */
 	uint64_t nb_iteration_looped;
-	uint32_t padding[9];
+	/*
+	 * Represents empty and non empty polls
+	 * of rte_eth_rx_burst();
+	 * ep_nep[0] holds non empty polls
+	 * i.e. 0 < nb_rx <= MAX_BURST
+	 * ep_nep[1] holds empty polls.
+	 * i.e. nb_rx == 0
+	 */
+	uint64_t ep_nep[2];
+	/*
+	 * Represents full and empty+partial
+	 * polls of rte_eth_rx_burst();
+	 * ep_nep[0] holds empty+partial polls.
+	 * i.e. 0 <= nb_rx < MAX_BURST
+	 * ep_nep[1] holds full polls
+	 * i.e. nb_rx == MAX_BURST
+	 */
+	uint64_t fp_nfp[2];
+	enum busy_rate br;
+	rte_spinlock_t telemetry_lock;
 } __rte_cache_aligned;
 
 static struct lcore_conf lcore_conf[RTE_MAX_LCORE] __rte_cache_aligned;
@@ -362,7 +425,7 @@ static uint8_t  freq_tlb[] = {14, 9, 1};
 
 static int is_done(void)
 {
-	return empty_poll_stop;
+	return quit_signal;
 }
 
 /* exit signal handler */
@@ -374,8 +437,9 @@ signal_exit_now(int sigtype)
 	int ret;
 
 	if (sigtype == SIGINT) {
-		if (empty_poll_on)
-			empty_poll_stop = true;
+		if (app_mode == APP_MODE_EMPTY_POLL ||
+				app_mode == APP_MODE_TELEMETRY)
+			quit_signal = true;
 
 
 		for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++) {
@@ -390,7 +454,7 @@ signal_exit_now(int sigtype)
 							"core%u\n", lcore_id);
 		}
 
-		if (!empty_poll_on) {
+		if (app_mode != APP_MODE_EMPTY_POLL) {
 			RTE_ETH_FOREACH_DEV(portid) {
 				if ((enabled_port_mask & (1 << portid)) == 0)
 					continue;
@@ -401,7 +465,7 @@ signal_exit_now(int sigtype)
 		}
 	}
 
-	if (!empty_poll_on)
+	if (app_mode != APP_MODE_EMPTY_POLL)
 		rte_exit(EXIT_SUCCESS, "User forced exit\n");
 }
 
@@ -871,6 +935,126 @@ static int event_register(struct lcore_conf *qconf)
 }
 /* main processing loop */
 static int
+main_telemetry_loop(__attribute__((unused)) void *dummy)
+{
+	struct rte_mbuf *pkts_burst[MAX_PKT_BURST];
+	unsigned int lcore_id;
+	uint64_t prev_tsc, diff_tsc, cur_tsc, prev_tel_tsc;
+	int i, j, nb_rx;
+	uint8_t queueid;
+	uint16_t portid;
+	struct lcore_conf *qconf;
+	struct lcore_rx_queue *rx_queue;
+	uint64_t ep_nep[2] = {0}, fp_nfp[2] = {0};
+	uint64_t poll_count;
+	enum busy_rate br;
+
+	const uint64_t drain_tsc = (rte_get_tsc_hz() + US_PER_S - 1) /
+					US_PER_S * BURST_TX_DRAIN_US;
+
+	poll_count = 0;
+	prev_tsc = 0;
+	prev_tel_tsc = 0;
+
+	lcore_id = rte_lcore_id();
+	qconf = &lcore_conf[lcore_id];
+
+	if (qconf->n_rx_queue == 0) {
+		RTE_LOG(INFO, L3FWD_POWER, "lcore %u has nothing to do\n",
+			lcore_id);
+		return 0;
+	}
+
+	RTE_LOG(INFO, L3FWD_POWER, "entering main telemetry loop on lcore %u\n",
+		lcore_id);
+
+	for (i = 0; i < qconf->n_rx_queue; i++) {
+		portid = qconf->rx_queue_list[i].port_id;
+		queueid = qconf->rx_queue_list[i].queue_id;
+		RTE_LOG(INFO, L3FWD_POWER, " -- lcoreid=%u portid=%u "
+			"rxqueueid=%hhu\n", lcore_id, portid, queueid);
+	}
+
+	while (!is_done()) {
+
+		cur_tsc = rte_rdtsc();
+		/*
+		 * TX burst queue drain
+		 */
+		diff_tsc = cur_tsc - prev_tsc;
+		if (unlikely(diff_tsc > drain_tsc)) {
+			for (i = 0; i < qconf->n_tx_port; ++i) {
+				portid = qconf->tx_port_id[i];
+				rte_eth_tx_buffer_flush(portid,
+						qconf->tx_queue_id[portid],
+						qconf->tx_buffer[portid]);
+			}
+			prev_tsc = cur_tsc;
+		}
+
+		/*
+		 * Read packet from RX queues
+		 */
+		for (i = 0; i < qconf->n_rx_queue; ++i) {
+			rx_queue = &(qconf->rx_queue_list[i]);
+			portid = rx_queue->port_id;
+			queueid = rx_queue->queue_id;
+
+			nb_rx = rte_eth_rx_burst(portid, queueid, pkts_burst,
+								MAX_PKT_BURST);
+			ep_nep[nb_rx == 0]++;
+			fp_nfp[nb_rx == MAX_PKT_BURST]++;
+			poll_count++;
+			if (unlikely(nb_rx == 0))
+				continue;
+
+			/* Prefetch first packets */
+			for (j = 0; j < PREFETCH_OFFSET && j < nb_rx; j++) {
+				rte_prefetch0(rte_pktmbuf_mtod(
+						pkts_burst[j], void *));
+			}
+
+			/* Prefetch and forward already prefetched packets */
+			for (j = 0; j < (nb_rx - PREFETCH_OFFSET); j++) {
+				rte_prefetch0(rte_pktmbuf_mtod(pkts_burst[
+						j + PREFETCH_OFFSET], void *));
+				l3fwd_simple_forward(pkts_burst[j], portid,
+								qconf);
+			}
+
+			/* Forward remaining prefetched packets */
+			for (; j < nb_rx; j++) {
+				l3fwd_simple_forward(pkts_burst[j], portid,
+								qconf);
+			}
+		}
+		if (unlikely(poll_count >= DEFAULT_COUNT)) {
+			diff_tsc = cur_tsc - prev_tel_tsc;
+			if (diff_tsc >= MAX_CYCLES) {
+				br = FULL;
+			} else if (diff_tsc > MIN_CYCLES &&
+					diff_tsc < MAX_CYCLES) {
+				br = PARTIAL;
+			} else {
+				br = ZERO;
+			}
+			poll_count = 0;
+			prev_tel_tsc = cur_tsc;
+			/* update stats for telemetry */
+			rte_spinlock_lock(&stats[lcore_id].telemetry_lock);
+			stats[lcore_id].ep_nep[0] = ep_nep[0];
+			stats[lcore_id].ep_nep[1] = ep_nep[1];
+			stats[lcore_id].fp_nfp[0] = fp_nfp[0];
+			stats[lcore_id].fp_nfp[1] = fp_nfp[1];
+			stats[lcore_id].br = br;
+			rte_spinlock_unlock(&stats[lcore_id].telemetry_lock);
+		}
+	}
+
+	return 0;
+}
+/* main processing loop */
+static int
 main_empty_poll_loop(__attribute__((unused)) void *dummy)
 {
 	struct rte_mbuf *pkts_burst[MAX_PKT_BURST];
@@ -1192,6 +1376,11 @@ check_lcore_params(void)
 			printf("warning: lcore %hhu is on socket %d with numa "
 						"off\n", lcore, socketid);
 		}
+		if (app_mode == APP_MODE_TELEMETRY && lcore == rte_lcore_id()) {
+			printf("cannot enable master core %d in config for telemetry mode\n",
+				rte_lcore_id());
+			return -1;
+		}
 	}
 	return 0;
 }
@@ -1276,7 +1465,9 @@ print_usage(const char *prgname)
 		" which max packet len is PKTLEN in decimal (64-9600)\n"
 		"  --parse-ptype: parse packet type by software\n"
 		"  --empty-poll: enable empty poll detection"
-		" follow (training_flag, high_threshold, med_threshold)\n",
+		" follow (training_flag, high_threshold, med_threshold)\n"
+		" --telemetry: enable telemetry mode, to update"
+		" empty polls, full polls, and core busyness to telemetry\n",
 		prgname);
 }
 
@@ -1419,6 +1610,7 @@ parse_ep_config(const char *q_arg)
 
 }
 #define CMD_LINE_OPT_PARSE_PTYPE "parse-ptype"
+#define CMD_LINE_OPT_TELEMETRY "telemetry"
 
 /* Parse the argument given in the command line of the application */
 static int
@@ -1437,6 +1629,7 @@ parse_args(int argc, char **argv)
 		{"enable-jumbo", 0, 0, 0},
 		{"empty-poll", 1, 0, 0},
 		{CMD_LINE_OPT_PARSE_PTYPE, 0, 0, 0},
+		{CMD_LINE_OPT_TELEMETRY, 0, 0, 0},
 		{NULL, 0, 0, 0}
 	};
 
@@ -1510,8 +1703,11 @@ parse_args(int argc, char **argv)
 
 			if (!strncmp(lgopts[option_index].name,
 						"empty-poll", 10)) {
-				printf("empty-poll is enabled\n");
-				empty_poll_on = true;
+				if (app_mode == APP_MODE_TELEMETRY) {
+					printf(" empty-poll cannot be enabled as telemetry mode is enabled\n");
+					return -1;
+				}
+				app_mode = APP_MODE_EMPTY_POLL;
 				ret = parse_ep_config(optarg);
 
 				if (ret) {
@@ -1519,7 +1715,18 @@ parse_args(int argc, char **argv)
 					print_usage(prgname);
 					return -1;
 				}
+				printf("empty-poll is enabled\n");
+			}
 
+			if (!strncmp(lgopts[option_index].name,
+					CMD_LINE_OPT_TELEMETRY,
+					sizeof(CMD_LINE_OPT_TELEMETRY))) {
+				if (app_mode == APP_MODE_EMPTY_POLL) {
+					printf("telemetry mode cannot be enabled as empty poll mode is enabled\n");
+					return -1;
+				}
+				app_mode = APP_MODE_TELEMETRY;
+				printf("telemetry mode is enabled\n");
 			}
 
 			if (!strncmp(lgopts[option_index].name,
@@ -1871,6 +2078,52 @@ init_power_library(void)
 	return ret;
 }
 static void
+update_telemetry(__attribute__((unused)) struct rte_timer *tim,
+		__attribute__((unused)) void *arg)
+{
+	unsigned int lcore_id = rte_lcore_id();
+	struct lcore_conf *qconf;
+	uint64_t app_eps = 0, app_fps = 0, app_br = 0;
+	uint64_t values[3] = {0};
+	int ret;
+	uint64_t count = 0;
+
+	RTE_LCORE_FOREACH_SLAVE(lcore_id) {
+		qconf = &lcore_conf[lcore_id];
+		if (qconf->n_rx_queue == 0)
+			continue;
+		count++;
+		rte_spinlock_lock(&stats[lcore_id].telemetry_lock);
+		app_eps += stats[lcore_id].ep_nep[1];
+		app_fps += stats[lcore_id].fp_nfp[1];
+		app_br += stats[lcore_id].br;
+		rte_spinlock_unlock(&stats[lcore_id].telemetry_lock);
+	}
+
+	values[0] = round(app_eps/count);
+	values[1] = round(app_fps/count);
+	values[2] = round(app_br/count);
+	ret = rte_metrics_update_values(RTE_METRICS_GLOBAL, telstats_index,
+					values, RTE_DIM(values));
+	if (ret < 0)
+		RTE_LOG(WARNING, POWER, "failed to update metrcis\n");
+}
+static void
+telemetry_setup_timer(void)
+{
+	int lcore_id = rte_lcore_id();
+	uint64_t hz = rte_get_timer_hz();
+	uint64_t ticks;
+
+	ticks = hz / TELEMETRY_INTERVALS_PER_SEC;
+	rte_timer_reset_sync(&telemetry_timer,
+			ticks,
+			PERIODICAL,
+			lcore_id,
+			update_telemetry,
+			NULL);
+}
+static void
 empty_poll_setup_timer(void)
 {
 	int lcore_id = rte_lcore_id();
@@ -1904,7 +2157,10 @@ launch_timer(unsigned int lcore_id)
 
 	RTE_LOG(INFO, POWER, "Bring up the Timer\n");
 
-	empty_poll_setup_timer();
+	if (app_mode == APP_MODE_EMPTY_POLL)
+		empty_poll_setup_timer();
+	else
+		telemetry_setup_timer();
 
 	cycles_10ms = rte_get_timer_hz() / 100;
 
@@ -1939,6 +2195,8 @@ main(int argc, char **argv)
 	uint32_t dev_rxq_num, dev_txq_num;
 	uint8_t nb_rx_queue, queue, socketid;
 	uint16_t portid;
+	uint8_t num_telstats = RTE_DIM(telstats_strings);
+	const char *ptr_strings[num_telstats];
 
 	/* catch SIGINT and restore cpufreq governor to ondemand */
 	signal(SIGINT, signal_exit_now);
@@ -2105,7 +2363,7 @@ main(int argc, char **argv)
 		if (rte_lcore_is_enabled(lcore_id) == 0)
 			continue;
 
-		if (empty_poll_on == false) {
+		if (app_mode == APP_MODE_LEGACY) {
 			/* init timer structures for each enabled lcore */
 			rte_timer_init(&power_timers[lcore_id]);
 			hz = rte_get_timer_hz();
@@ -2184,7 +2442,7 @@ main(int argc, char **argv)
 
 	check_all_ports_link_status(enabled_port_mask);
 
-	if (empty_poll_on == true) {
+	if (app_mode == APP_MODE_EMPTY_POLL) {
 
 		if (empty_poll_train) {
 			policy.state = TRAINING;
@@ -2203,15 +2461,34 @@ main(int argc, char **argv)
 
 
 	/* launch per-lcore init on every lcore */
-	if (empty_poll_on == false) {
+	if (app_mode == APP_MODE_LEGACY) {
 		rte_eal_mp_remote_launch(main_loop, NULL, CALL_MASTER);
-	} else {
+	} else if (app_mode == APP_MODE_EMPTY_POLL) {
 		empty_poll_stop = false;
 		rte_eal_mp_remote_launch(main_empty_poll_loop, NULL,
 				SKIP_MASTER);
+	} else {
+		/* Init metrics library */
+		rte_metrics_init(rte_socket_id());
+		/** Register stats with metrics library */
+		for (unsigned int i = 0; i < num_telstats; i++)
+			ptr_strings[i] = telstats_strings[i].name;
+
+		ret = rte_metrics_reg_names(ptr_strings, num_telstats);
+		if (ret >= 0)
+			telstats_index = ret;
+		else
+			rte_exit(EXIT_FAILURE, "failed to register metrics names");
+
+		RTE_LCORE_FOREACH_SLAVE(lcore_id) {
+			rte_spinlock_init(&stats[lcore_id].telemetry_lock);
+		}
+		rte_timer_init(&telemetry_timer);
+		rte_eal_mp_remote_launch(main_telemetry_loop, NULL,
+						SKIP_MASTER);
 	}
 
-	if (empty_poll_on == true)
+	if (app_mode == APP_MODE_EMPTY_POLL || app_mode == APP_MODE_TELEMETRY)
 		launch_timer(rte_lcore_id());
 
 	RTE_LCORE_FOREACH_SLAVE(lcore_id) {
@@ -2219,7 +2496,7 @@ main(int argc, char **argv)
 			return -1;
 	}
 
-	if (empty_poll_on)
+	if (app_mode == APP_MODE_EMPTY_POLL)
 		rte_power_empty_poll_stat_free();
 
 	return 0;
diff --git a/examples/l3fwd-power/meson.build b/examples/l3fwd-power/meson.build
index 2c84123b6..b38a7a0d7 100644
--- a/examples/l3fwd-power/meson.build
+++ b/examples/l3fwd-power/meson.build
@@ -10,7 +10,7 @@ if not is_linux
 	build = false
 endif
 allow_experimental_apis = true
-deps += ['power', 'timer', 'lpm', 'hash']
+deps += ['power', 'timer', 'lpm', 'hash', 'metrics']
 sources = files(
 	'main.c', 'perf_core.c'
 )
-- 
2.21.0