[dpdk-dev] [PATCH v5 1/2] lib/librte_power: traffic pattern aware power control

[Radu Nicolau <radu.nicolau@intel.com>]

From: Liang Ma <liang.j.ma@intel.com>

1. Abstract

For packet processing workloads such as DPDK polling is continuous.
This means CPU cores always show 100% busy independent of how much work
those cores are doing. It is critical to accurately determine how busy
a core is hugely important for the following reasons:

   * No indication of overload conditions

   * User do not know how much real load is on a system meaning resulted in
     wasted energy as no power management is utilized

Tried and failed schemes include calculating the cycles required from
the load on the core, in other words the busyness. For example,
how many cycles it costs to handle each packet and determining the
frequency cost per core. Due to the varying nature of traffic, types of
frames and cost in cycles to process, this mechanism becomes complex
quickly where a simple scheme is required to solve the problems.

2. Proposed solution

For all polling mechanism, the proposed solution focus on how many times
empty poll executed instead of calculating how many cycles it cost to
handle each packet. The less empty poll number means current core is busy
with processing workload, therefore,  the higher frequency is needed. The
high empty poll number indicate current core has lots spare time,
therefore, we can lower the frequency.

2.1 Power state definition:

	LOW:  the frequency is used for purge mode.

	MED:  the frequency is used to process modest traffic workload.

	HIGH: the frequency is used to process busy traffic workload.

2.2 There are two phases to establish the power management system:

	a.Initialization/Training phase. There is no traffic pass-through,
	  the system will test average empty poll numbers  with
	  LOW/MED/HIGH  power state. Those average empty poll numbers
	  will be the baseline
	  for the normal phase. The system will collect all core's counter
	  every 100ms. The Training phase will take 5 seconds.

	b.Normal phase. When the real traffic pass-though, the system will
	  compare run-time empty poll moving average value with base line
	  then make decision to move to HIGH power state of MED  power
	  state. The system will collect all core's counter every 10ms.

3. Proposed  API

1.  rte_power_empty_poll_stat_init(void);
which is used to initialize the power management system.
 
2.  rte_power_empty_poll_stat_free(void);
which is used to free the resource hold by power management system.
 
3.  rte_power_empty_poll_stat_update(unsigned int lcore_id);
which is used to update specific core empty poll counter, not thread safe
 
4.  rte_power_poll_stat_update(unsigned int lcore_id, uint8_t nb_pkt);
which is used to update specific core valid poll counter, not thread safe
 
5.  rte_power_empty_poll_stat_fetch(unsigned int lcore_id);
which is used to get specific core empty poll counter.
 
6.  rte_power_poll_stat_fetch(unsigned int lcore_id);
which is used to get specific core valid poll counter.

7.  rte_power_empty_poll_set_freq(enum freq_val index, uint32_t limit);
which allow user customize the frequency of power state.

8.  rte_power_empty_poll_setup_timer(void);
which is used to setup the timer/callback to process all above counter.

ChangeLog:
v2: fix some coding style issues
v3: rename the filename, API name.
v4: updated makefile and symbol list
v5: marked API as experimental

Signed-off-by: Liang Ma <liang.j.ma@intel.com>
Signed-off-by: Radu Nicolau <radu.nicolau@intel.com>
Acked-by: David Hunt <david.hunt@intel.com>
---
 lib/librte_power/Makefile               |   5 +-
 lib/librte_power/meson.build            |   5 +-
 lib/librte_power/rte_power_empty_poll.c | 521 ++++++++++++++++++++++++++++++++
 lib/librte_power/rte_power_empty_poll.h | 214 +++++++++++++
 lib/librte_power/rte_power_version.map  |  15 +-
 5 files changed, 755 insertions(+), 5 deletions(-)
 create mode 100644 lib/librte_power/rte_power_empty_poll.c
 create mode 100644 lib/librte_power/rte_power_empty_poll.h

diff --git a/lib/librte_power/Makefile b/lib/librte_power/Makefile
index 6f85e88..9bec668 100644
--- a/lib/librte_power/Makefile
+++ b/lib/librte_power/Makefile
@@ -7,7 +7,7 @@ include $(RTE_SDK)/mk/rte.vars.mk
 LIB = librte_power.a
 
 CFLAGS += $(WERROR_FLAGS) -I$(SRCDIR) -O3 -fno-strict-aliasing
-LDLIBS += -lrte_eal
+LDLIBS += -lrte_eal -lrte_timer
 
 EXPORT_MAP := rte_power_version.map
 
@@ -16,8 +16,9 @@ LIBABIVER := 1
 # all source are stored in SRCS-y
 SRCS-$(CONFIG_RTE_LIBRTE_POWER) := rte_power.c power_acpi_cpufreq.c
 SRCS-$(CONFIG_RTE_LIBRTE_POWER) += power_kvm_vm.c guest_channel.c
+SRCS-$(CONFIG_RTE_LIBRTE_POWER) += rte_power_empty_poll.c
 
 # install this header file
-SYMLINK-$(CONFIG_RTE_LIBRTE_POWER)-include := rte_power.h
+SYMLINK-$(CONFIG_RTE_LIBRTE_POWER)-include := rte_power.h  rte_power_empty_poll.h
 
 include $(RTE_SDK)/mk/rte.lib.mk
diff --git a/lib/librte_power/meson.build b/lib/librte_power/meson.build
index 253173f..63957eb 100644
--- a/lib/librte_power/meson.build
+++ b/lib/librte_power/meson.build
@@ -5,5 +5,6 @@ if host_machine.system() != 'linux'
 	build = false
 endif
 sources = files('rte_power.c', 'power_acpi_cpufreq.c',
-		'power_kvm_vm.c', 'guest_channel.c')
-headers = files('rte_power.h')
+		'power_kvm_vm.c', 'guest_channel.c',
+		'rte_power_empty_poll.c')
+headers = files('rte_power.h','rte_power_empty_poll.h')
diff --git a/lib/librte_power/rte_power_empty_poll.c b/lib/librte_power/rte_power_empty_poll.c
new file mode 100644
index 0000000..923226b
--- /dev/null
+++ b/lib/librte_power/rte_power_empty_poll.c
@@ -0,0 +1,521 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2010-2018 Intel Corporation
+ */
+
+#include <string.h>
+
+#include <rte_lcore.h>
+#include <rte_cycles.h>
+#include <rte_atomic.h>
+#include <rte_malloc.h>
+
+#include "rte_power.h"
+#include "rte_power_empty_poll.h"
+
+#define INTERVALS_PER_SECOND 100     /* (10ms) */
+#define SECONDS_TO_TRAIN_FOR  5
+#define DEFAULT_MED_TO_HIGH_PERCENT_THRESHOLD 70
+#define DEFAULT_HIGH_TO_MED_PERCENT_THRESHOLD 30
+#define DEFAULT_CYCLES_PER_PACKET 800
+
+static struct ep_params *ep_params;
+static uint32_t med_to_high_threshold = DEFAULT_MED_TO_HIGH_PERCENT_THRESHOLD;
+static uint32_t high_to_med_threshold = DEFAULT_HIGH_TO_MED_PERCENT_THRESHOLD;
+
+static uint32_t avail_freqs[RTE_MAX_LCORE][NUM_FREQS];
+
+static uint32_t total_avail_freqs[RTE_MAX_LCORE];
+
+static uint32_t freq_index[NUM_FREQ];
+
+static uint32_t
+get_freq_index(enum freq_val index)
+{
+	return freq_index[index];
+}
+
+
+static int
+set_power_freq(int lcore_id, enum freq_val freq, bool specific_freq)
+{
+	int err = 0;
+	uint32_t power_freq_index;
+	if (!specific_freq)
+		power_freq_index = get_freq_index(freq);
+	else
+		power_freq_index = freq;
+
+	err = rte_power_set_freq(lcore_id, power_freq_index);
+
+	return err;
+}
+
+
+static inline void __attribute__((always_inline))
+exit_training_state(struct priority_worker *poll_stats)
+{
+	RTE_SET_USED(poll_stats);
+}
+
+static inline void __attribute__((always_inline))
+enter_training_state(struct priority_worker *poll_stats)
+{
+	poll_stats->iter_counter = 0;
+	poll_stats->cur_freq = LOW;
+	poll_stats->queue_state = TRAINING;
+}
+
+static inline void __attribute__((always_inline))
+enter_normal_state(struct priority_worker *poll_stats)
+{
+	/* Clear the averages arrays and strs */
+	memset(poll_stats->edpi_av, 0, sizeof(poll_stats->edpi_av));
+	poll_stats->ec = 0;
+	memset(poll_stats->ppi_av, 0, sizeof(poll_stats->ppi_av));
+	poll_stats->pc = 0;
+
+	poll_stats->cur_freq = MED;
+	poll_stats->iter_counter = 0;
+	poll_stats->threshold_ctr = 0;
+	poll_stats->queue_state = MED_NORMAL;
+	set_power_freq(poll_stats->lcore_id, MED, false);
+
+	/* Try here */
+	poll_stats->thresh[MED].threshold_percent = med_to_high_threshold;
+	poll_stats->thresh[HGH].threshold_percent = high_to_med_threshold;
+}
+
+static inline void __attribute__((always_inline))
+enter_busy_state(struct priority_worker *poll_stats)
+{
+	memset(poll_stats->edpi_av, 0, sizeof(poll_stats->edpi_av));
+	poll_stats->ec = 0;
+	memset(poll_stats->ppi_av, 0, sizeof(poll_stats->ppi_av));
+	poll_stats->pc = 0;
+
+	poll_stats->cur_freq = HGH;
+	poll_stats->iter_counter = 0;
+	poll_stats->threshold_ctr = 0;
+	poll_stats->queue_state = HGH_BUSY;
+	set_power_freq(poll_stats->lcore_id, HGH, false);
+}
+
+static inline void __attribute__((always_inline))
+enter_purge_state(struct priority_worker *poll_stats)
+{
+	poll_stats->iter_counter = 0;
+	poll_stats->queue_state = LOW_PURGE;
+}
+
+static inline void __attribute__((always_inline))
+set_state(struct priority_worker *poll_stats,
+		enum queue_state new_state)
+{
+	enum queue_state old_state = poll_stats->queue_state;
+	if (old_state != new_state) {
+
+		/* Call any old state exit functions */
+		if (old_state == TRAINING)
+			exit_training_state(poll_stats);
+
+		/* Call any new state entry functions */
+		if (new_state == TRAINING)
+			enter_training_state(poll_stats);
+		if (new_state == MED_NORMAL)
+			enter_normal_state(poll_stats);
+		if (new_state == HGH_BUSY)
+			enter_busy_state(poll_stats);
+		if (new_state == LOW_PURGE)
+			enter_purge_state(poll_stats);
+	}
+}
+
+
+static void
+update_training_stats(struct priority_worker *poll_stats,
+		uint32_t freq,
+		bool specific_freq,
+		uint32_t max_train_iter)
+{
+	RTE_SET_USED(specific_freq);
+
+	char pfi_str[32];
+	uint64_t p0_empty_deq;
+
+	sprintf(pfi_str, "%02d", freq);
+
+	if (poll_stats->cur_freq == freq &&
+			poll_stats->thresh[freq].trained == false) {
+		if (poll_stats->thresh[freq].cur_train_iter == 0) {
+
+			set_power_freq(poll_stats->lcore_id,
+					freq, specific_freq);
+
+			poll_stats->empty_dequeues_prev =
+				poll_stats->empty_dequeues;
+
+			poll_stats->thresh[freq].cur_train_iter++;
+
+			return;
+		} else if (poll_stats->thresh[freq].cur_train_iter
+				<= max_train_iter) {
+
+			p0_empty_deq = poll_stats->empty_dequeues -
+				poll_stats->empty_dequeues_prev;
+
+			poll_stats->empty_dequeues_prev =
+				poll_stats->empty_dequeues;
+
+			poll_stats->thresh[freq].base_edpi += p0_empty_deq;
+			poll_stats->thresh[freq].cur_train_iter++;
+
+		} else {
+			if (poll_stats->thresh[freq].trained == false) {
+				poll_stats->thresh[freq].base_edpi =
+					poll_stats->thresh[freq].base_edpi /
+					max_train_iter;
+
+				/* Add on a factor of 0.05%, this should remove any */
+				/* false negatives when the system is 0% busy */
+				poll_stats->thresh[freq].base_edpi +=
+					poll_stats->thresh[freq].base_edpi / 2000;
+
+				poll_stats->thresh[freq].trained = true;
+				poll_stats->cur_freq++;
+
+			}
+		}
+	}
+}
+
+static inline uint32_t __attribute__((always_inline))
+update_stats(struct priority_worker *poll_stats)
+{
+	uint64_t tot_edpi = 0, tot_ppi = 0;
+	uint32_t j, percent;
+
+	struct priority_worker *s = poll_stats;
+
+	uint64_t cur_edpi = s->empty_dequeues - s->empty_dequeues_prev;
+
+	s->empty_dequeues_prev = s->empty_dequeues;
+
+	uint64_t ppi = s->num_dequeue_pkts - s->num_dequeue_pkts_prev;
+
+	s->num_dequeue_pkts_prev = s->num_dequeue_pkts;
+
+	if (s->thresh[s->cur_freq].base_edpi < cur_edpi)
+		return 1000UL; /* Value to make us fail */
+
+	s->edpi_av[s->ec++ % BINS_AV] = cur_edpi;
+	s->ppi_av[s->pc++ % BINS_AV] = ppi;
+
+	for (j = 0; j < BINS_AV; j++) {
+		tot_edpi += s->edpi_av[j];
+		tot_ppi += s->ppi_av[j];
+	}
+
+	tot_edpi = tot_edpi / BINS_AV;
+
+	percent = 100 - (uint32_t)((float)tot_edpi /
+			(float)s->thresh[s->cur_freq].base_edpi * 100);
+
+	return (uint32_t)percent;
+}
+
+
+static inline void  __attribute__((always_inline))
+update_stats_normal(struct priority_worker *poll_stats)
+{
+	uint32_t percent;
+
+	if (poll_stats->thresh[poll_stats->cur_freq].base_edpi == 0)
+		return;
+
+	percent = update_stats(poll_stats);
+
+	if (percent > 100)
+		return;
+
+	if (poll_stats->cur_freq == LOW)
+		RTE_LOG(INFO, POWER, "Purge Mode is not supported\n");
+	else if (poll_stats->cur_freq == MED) {
+
+		if (percent >
+			poll_stats->thresh[poll_stats->cur_freq].threshold_percent) {
+
+			if (poll_stats->threshold_ctr < INTERVALS_PER_SECOND)
+				poll_stats->threshold_ctr++;
+			else
+				set_state(poll_stats, HGH_BUSY);
+
+		} else {
+			/* reset */
+			poll_stats->threshold_ctr = 0;
+		}
+
+	} else if (poll_stats->cur_freq == HGH) {
+
+		if (percent <
+			poll_stats->thresh[poll_stats->cur_freq].threshold_percent) {
+
+			if (poll_stats->threshold_ctr < INTERVALS_PER_SECOND)
+				poll_stats->threshold_ctr++;
+			else
+				set_state(poll_stats, MED_NORMAL);
+		} else
+			/* reset */
+			poll_stats->threshold_ctr = 0;
+
+
+	}
+}
+
+static int
+empty_poll_trainning(struct priority_worker *poll_stats,
+		uint32_t max_train_iter)
+{
+
+	if (poll_stats->iter_counter < INTERVALS_PER_SECOND) {
+		poll_stats->iter_counter++;
+		return 0;
+	}
+
+
+	update_training_stats(poll_stats,
+			LOW,
+			false,
+			max_train_iter);
+
+	update_training_stats(poll_stats,
+			MED,
+			false,
+			max_train_iter);
+
+	update_training_stats(poll_stats,
+			HGH,
+			false,
+			max_train_iter);
+
+
+	if (poll_stats->thresh[LOW].trained == true
+			&& poll_stats->thresh[MED].trained == true
+			&& poll_stats->thresh[HGH].trained == true) {
+
+		set_state(poll_stats, MED_NORMAL);
+
+		RTE_LOG(INFO, POWER, "Training is Complete for %d\n",
+				poll_stats->lcore_id);
+	}
+
+	return 0;
+}
+
+static void
+empty_poll_detection(struct rte_timer *tim,
+		void *arg)
+{
+
+	uint32_t i;
+
+	struct priority_worker *poll_stats;
+
+	RTE_SET_USED(tim);
+
+	RTE_SET_USED(arg);
+
+	for (i = 0; i < NUM_NODES; i++) {
+
+		poll_stats = &(ep_params->wrk_data.wrk_stats[i]);
+
+		if (rte_lcore_is_enabled(poll_stats->lcore_id) == 0)
+			continue;
+
+		switch (poll_stats->queue_state) {
+		case(TRAINING):
+			empty_poll_trainning(poll_stats,
+					ep_params->max_train_iter);
+			break;
+
+		case(HGH_BUSY):
+		case(MED_NORMAL):
+			update_stats_normal(poll_stats);
+
+			break;
+
+		case(LOW_PURGE):
+			break;
+		default:
+			break;
+
+		}
+
+	}
+
+}
+
+int
+rte_power_empty_poll_stat_init(void)
+{
+	uint32_t i;
+	/* Allocate the ep_params structure */
+	ep_params = rte_zmalloc_socket(NULL,
+			sizeof(struct ep_params),
+			0,
+			rte_socket_id());
+
+	if (!ep_params)
+		rte_panic("Cannot allocate heap memory for ep_params "
+				"for socket %d\n", rte_socket_id());
+
+	freq_index[LOW] = 14;
+	freq_index[MED] = 9;
+	freq_index[HGH] = 1;
+
+	RTE_LOG(INFO, POWER, "Initialize the Empty Poll\n");
+
+	/* 5 seconds worth of training */
+	ep_params->max_train_iter = INTERVALS_PER_SECOND * SECONDS_TO_TRAIN_FOR;
+
+	struct stats_data *w = &ep_params->wrk_data;
+
+	/* initialize all wrk_stats state */
+	for (i = 0; i < NUM_NODES; i++) {
+
+		if (rte_lcore_is_enabled(i) == 0)
+			continue;
+
+		set_state(&w->wrk_stats[i], TRAINING);
+		/*init the freqs table */
+		total_avail_freqs[i] = rte_power_freqs(i,
+				avail_freqs[i],
+				NUM_FREQS);
+
+		if (get_freq_index(LOW) > total_avail_freqs[i])
+			return -1;
+
+	}
+
+
+	return 0;
+}
+
+void
+rte_power_empty_poll_stat_free(void)
+{
+
+	RTE_LOG(INFO, POWER, "Close the Empty Poll\n");
+
+	if (ep_params != NULL)
+		rte_free(ep_params);
+}
+
+int
+rte_power_empty_poll_stat_update(unsigned int lcore_id)
+{
+	struct priority_worker *poll_stats;
+
+	if (lcore_id >= NUM_NODES)
+		return -1;
+
+	poll_stats = &(ep_params->wrk_data.wrk_stats[lcore_id]);
+
+	if (poll_stats->lcore_id == 0)
+		poll_stats->lcore_id = lcore_id;
+
+	poll_stats->empty_dequeues++;
+
+	return 0;
+}
+
+int
+rte_power_poll_stat_update(unsigned int lcore_id, uint8_t nb_pkt)
+{
+
+	struct priority_worker *poll_stats;
+
+	if (lcore_id >= NUM_NODES)
+		return -1;
+
+	poll_stats = &(ep_params->wrk_data.wrk_stats[lcore_id]);
+
+	if (poll_stats->lcore_id == 0)
+		poll_stats->lcore_id = lcore_id;
+
+	poll_stats->num_dequeue_pkts += nb_pkt;
+
+	return 0;
+}
+
+
+uint64_t
+rte_power_empty_poll_stat_fetch(unsigned int lcore_id)
+{
+	struct priority_worker *poll_stats;
+
+	if (lcore_id >= NUM_NODES)
+		return -1;
+
+	poll_stats = &(ep_params->wrk_data.wrk_stats[lcore_id]);
+
+	if (poll_stats->lcore_id == 0)
+		poll_stats->lcore_id = lcore_id;
+
+	return poll_stats->empty_dequeues;
+}
+
+uint64_t
+rte_power_poll_stat_fetch(unsigned int lcore_id)
+{
+	struct priority_worker *poll_stats;
+
+	if (lcore_id >= NUM_NODES)
+		return -1;
+
+	poll_stats = &(ep_params->wrk_data.wrk_stats[lcore_id]);
+
+	if (poll_stats->lcore_id == 0)
+		poll_stats->lcore_id = lcore_id;
+
+	return poll_stats->num_dequeue_pkts;
+}
+
+void
+rte_power_empty_poll_set_freq(enum freq_val index, uint32_t limit)
+{
+	switch (index) {
+
+	case LOW:
+		freq_index[LOW] = limit;
+		break;
+
+	case MED:
+		freq_index[MED] = limit;
+		break;
+
+	case HGH:
+		freq_index[HGH] = limit;
+		break;
+	default:
+		break;
+	}
+}
+
+void
+rte_power_empty_poll_setup_timer(void)
+{
+	int lcore_id = rte_lcore_id();
+	uint64_t hz = rte_get_timer_hz();
+
+	struct  ep_params *ep_ptr = ep_params;
+
+	ep_ptr->interval_ticks = hz / INTERVALS_PER_SECOND;
+
+	rte_timer_reset_sync(&ep_ptr->timer0,
+			ep_ptr->interval_ticks,
+			PERIODICAL,
+			lcore_id,
+			empty_poll_detection,
+			(void *)ep_ptr);
+
+}
diff --git a/lib/librte_power/rte_power_empty_poll.h b/lib/librte_power/rte_power_empty_poll.h
new file mode 100644
index 0000000..e276ee6
--- /dev/null
+++ b/lib/librte_power/rte_power_empty_poll.h
@@ -0,0 +1,214 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2010-2018 Intel Corporation
+ */
+
+#ifndef _RTE_EMPTY_POLL_H
+#define _RTE_EMPTY_POLL_H
+
+/**
+ * @file
+ * RTE Power Management
+ *
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ */
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <sys/queue.h>
+
+#include <rte_common.h>
+#include <rte_byteorder.h>
+#include <rte_log.h>
+#include <rte_string_fns.h>
+#include <rte_power.h>
+#include <rte_timer.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define NUM_FREQS 20
+
+#define BINS_AV 4 /* Has to be ^2 */
+
+#define DROP (NUM_DIRECTIONS * NUM_DEVICES)
+
+#define NUM_PRIORITIES          2
+
+#define NUM_NODES         31 /* Any reseanable prime number should work*/
+
+/* Processor Power State */
+enum freq_val {
+	LOW,
+	MED,
+	HGH,
+	NUM_FREQ = NUM_FREQS
+};
+
+
+/* Queue Polling State */
+enum queue_state {
+	TRAINING, /* NO TRAFFIC */
+	MED_NORMAL,   /* MED */
+	HGH_BUSY,     /* HIGH */
+	LOW_PURGE,    /* LOW */
+};
+
+/* Queue Stats */
+struct freq_threshold {
+
+	uint64_t base_edpi;
+	bool trained;
+	uint32_t threshold_percent;
+	uint32_t cur_train_iter;
+};
+
+/* Each Worder Tread Empty Poll Stats */
+struct priority_worker {
+
+	/* Current dequeue and throughput counts */
+	/* These 2 are written to by the worker threads */
+	/* So keep them on their own cache line */
+	uint64_t empty_dequeues;
+	uint64_t num_dequeue_pkts;
+
+	enum queue_state queue_state;
+
+	uint64_t empty_dequeues_prev;
+	uint64_t num_dequeue_pkts_prev;
+
+	/* Used for training only */
+	struct freq_threshold thresh[NUM_FREQ];
+	enum freq_val cur_freq;
+
+	/* bucket arrays to calculate the averages */
+	uint64_t edpi_av[BINS_AV];
+	uint32_t  ec;
+	uint64_t ppi_av[BINS_AV];
+	uint32_t  pc;
+
+	uint32_t lcore_id;
+	uint32_t iter_counter;
+	uint32_t threshold_ctr;
+	uint32_t display_ctr;
+	uint8_t  dev_id;
+
+} __rte_cache_aligned;
+
+
+struct stats_data {
+
+	struct priority_worker wrk_stats[NUM_NODES];
+
+	/* flag to stop rx threads processing packets until training over */
+	bool start_rx;
+
+};
+
+/* Empty Poll Parameters */
+struct ep_params {
+
+	/* Timer related stuff */
+	uint64_t interval_ticks;
+	uint32_t max_train_iter;
+
+	struct rte_timer timer0;
+	struct stats_data wrk_data;
+};
+
+
+/**
+ * Initialize the power management system.
+ *
+ * @param void
+ *
+ * @return
+ *  - 0 on success.
+ *  - Negative on error.
+ */
+int __rte_experimental
+rte_power_empty_poll_stat_init(void);
+
+/**
+ * Free the resource hold by power management system.
+ */
+void __rte_experimental
+rte_power_empty_poll_stat_free(void);
+
+/**
+ * Update specific core empty poll counter
+ * It's not thread safe.
+ *
+ * @param lcore_id
+ *  lcore id
+ *
+ * @return
+ *  - 0 on success.
+ *  - Negative on error.
+ */
+int __rte_experimental
+rte_power_empty_poll_stat_update(unsigned int lcore_id);
+
+/**
+ * Update specific core valid poll counter, not thread safe.
+ *
+ * @param lcore_id
+ *  lcore id.
+ * @param nb_pkt
+ *  The packet number of one valid poll.
+ *
+ * @return
+ *  - 0 on success.
+ *  - Negative on error.
+ */
+int __rte_experimental
+rte_power_poll_stat_update(unsigned int lcore_id, uint8_t nb_pkt);
+
+/**
+ * Fetch specific core empty poll counter.
+ *
+ * @param lcore_id
+ *  lcore id
+ *
+ * @return
+ *  Current lcore empty poll counter value.
+ */
+uint64_t __rte_experimental
+rte_power_empty_poll_stat_fetch(unsigned int lcore_id);
+
+/**
+ * Fetch specific core valid poll counter.
+ *
+ * @param lcore_id
+ *  lcore id
+ *
+ * @return
+ *  Current lcore valid poll counter value.
+ */
+uint64_t __rte_experimental
+rte_power_poll_stat_fetch(unsigned int lcore_id);
+
+/**
+ * Allow user customize the index of power state.
+ *
+ * @param  index
+ *  The type of the queue power state
+ * @param  limit
+ *  The processor P-state offset value for that power state.
+ */
+void __rte_experimental
+rte_power_empty_poll_set_freq(enum freq_val index, uint32_t limit);
+
+/**
+ * Setup the timer/callback to process empty poll counter.
+ * Default timer resolution is 10ms.
+ */
+void __rte_experimental
+rte_power_empty_poll_setup_timer(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/lib/librte_power/rte_power_version.map b/lib/librte_power/rte_power_version.map
index 96dc42e..08470c6 100644
--- a/lib/librte_power/rte_power_version.map
+++ b/lib/librte_power/rte_power_version.map
@@ -25,4 +25,17 @@ DPDK_17.11 {
 	rte_power_freq_enable_turbo;
 	rte_power_turbo_status;
 
-} DPDK_2.0;
\ No newline at end of file
+} DPDK_2.0;
+
+EXPERIMENTAL {
+	global:
+
+	rte_power_empty_poll_set_freq;
+	rte_power_empty_poll_setup_timer;
+	rte_power_empty_poll_stat_fetch;
+	rte_power_empty_poll_stat_free;
+	rte_power_empty_poll_stat_init;
+	rte_power_empty_poll_stat_update;
+	rte_power_poll_stat_fetch;
+	rte_power_poll_stat_update;
+};
-- 
2.7.5