include/linux/net_dim.h - linux-mtk - Git at Google

 /*
  * Copyright (c) 2016, Mellanox Technologies. All rights reserved.
  * Copyright (c) 2017-2018, Broadcom Limited. All rights reserved.
  *
  * This software is available to you under a choice of one of two
  * licenses.  You may choose to be licensed under the terms of the GNU
  * General Public License (GPL) Version 2, available from the file
  * COPYING in the main directory of this source tree, or the
  * OpenIB.org BSD license below:
  *
  *     Redistribution and use in source and binary forms, with or
  *     without modification, are permitted provided that the following
  *     conditions are met:
  *
  *      - Redistributions of source code must retain the above
  *        copyright notice, this list of conditions and the following
  *        disclaimer.
  *
  *      - Redistributions in binary form must reproduce the above
  *        copyright notice, this list of conditions and the following
  *        disclaimer in the documentation and/or other materials
  *        provided with the distribution.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */

 #ifndef NET_DIM_H
 #define NET_DIM_H

 #include <linux/module.h>

 struct net_dim_cq_moder {
 	u16 usec;
 	u16 pkts;
 	u8 cq_period_mode;
 };

 struct net_dim_sample {
 	ktime_t time;
 	u32     pkt_ctr;
 	u32     byte_ctr;
 	u16     event_ctr;
 };

 struct net_dim_stats {
 	int ppms; /* packets per msec */
 	int bpms; /* bytes per msec */
 	int epms; /* events per msec */
 };

 struct net_dim { /* Adaptive Moderation */
 	u8                                      state;
 	struct net_dim_stats                    prev_stats;
 	struct net_dim_sample                   start_sample;
 	struct work_struct                      work;
 	u8                                      profile_ix;
 	u8                                      mode;
 	u8                                      tune_state;
 	u8                                      steps_right;
 	u8                                      steps_left;
 	u8                                      tired;
 };

 enum {
 	NET_DIM_CQ_PERIOD_MODE_START_FROM_EQE = 0x0,
 	NET_DIM_CQ_PERIOD_MODE_START_FROM_CQE = 0x1,
 	NET_DIM_CQ_PERIOD_NUM_MODES
 };

 /* Adaptive moderation logic */
 enum {
 	NET_DIM_START_MEASURE,
 	NET_DIM_MEASURE_IN_PROGRESS,
 	NET_DIM_APPLY_NEW_PROFILE,
 };

 enum {
 	NET_DIM_PARKING_ON_TOP,
 	NET_DIM_PARKING_TIRED,
 	NET_DIM_GOING_RIGHT,
 	NET_DIM_GOING_LEFT,
 };

 enum {
 	NET_DIM_STATS_WORSE,
 	NET_DIM_STATS_SAME,
 	NET_DIM_STATS_BETTER,
 };

 enum {
 	NET_DIM_STEPPED,
 	NET_DIM_TOO_TIRED,
 	NET_DIM_ON_EDGE,
 };

 #define NET_DIM_PARAMS_NUM_PROFILES 5
 /* Adaptive moderation profiles */
 #define NET_DIM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE 256
 #define NET_DIM_DEFAULT_TX_CQ_MODERATION_PKTS_FROM_EQE 128
 #define NET_DIM_DEF_PROFILE_CQE 1
 #define NET_DIM_DEF_PROFILE_EQE 1

 /* All profiles sizes must be NET_PARAMS_DIM_NUM_PROFILES */
 #define NET_DIM_RX_EQE_PROFILES { \
 	{1,   NET_DIM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
 	{8,   NET_DIM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
 	{64,  NET_DIM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
 	{128, NET_DIM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
 	{256, NET_DIM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
 }

 #define NET_DIM_RX_CQE_PROFILES { \
 	{2,  256},             \
 	{8,  128},             \
 	{16, 64},              \
 	{32, 64},              \
 	{64, 64}               \
 }

 #define NET_DIM_TX_EQE_PROFILES { \
 	{1,   NET_DIM_DEFAULT_TX_CQ_MODERATION_PKTS_FROM_EQE},  \
 	{8,   NET_DIM_DEFAULT_TX_CQ_MODERATION_PKTS_FROM_EQE},  \
 	{32,  NET_DIM_DEFAULT_TX_CQ_MODERATION_PKTS_FROM_EQE},  \
 	{64,  NET_DIM_DEFAULT_TX_CQ_MODERATION_PKTS_FROM_EQE},  \
 	{128, NET_DIM_DEFAULT_TX_CQ_MODERATION_PKTS_FROM_EQE}   \
 }

 #define NET_DIM_TX_CQE_PROFILES { \
 	{5,  128},  \
 	{8,  64},  \
 	{16, 32},  \
 	{32, 32},  \
 	{64, 32}   \
 }

 static const struct net_dim_cq_moder
 rx_profile[NET_DIM_CQ_PERIOD_NUM_MODES][NET_DIM_PARAMS_NUM_PROFILES] = {
 	NET_DIM_RX_EQE_PROFILES,
 	NET_DIM_RX_CQE_PROFILES,
 };

 static const struct net_dim_cq_moder
 tx_profile[NET_DIM_CQ_PERIOD_NUM_MODES][NET_DIM_PARAMS_NUM_PROFILES] = {
 	NET_DIM_TX_EQE_PROFILES,
 	NET_DIM_TX_CQE_PROFILES,
 };

 static inline struct net_dim_cq_moder
 net_dim_get_rx_moderation(u8 cq_period_mode, int ix)
 {
 	struct net_dim_cq_moder cq_moder = rx_profile[cq_period_mode][ix];

 	cq_moder.cq_period_mode = cq_period_mode;
 	return cq_moder;
 }

 static inline struct net_dim_cq_moder
 net_dim_get_def_rx_moderation(u8 cq_period_mode)
 {
 	u8 profile_ix = cq_period_mode == NET_DIM_CQ_PERIOD_MODE_START_FROM_CQE ?
 			NET_DIM_DEF_PROFILE_CQE : NET_DIM_DEF_PROFILE_EQE;

 	return net_dim_get_rx_moderation(cq_period_mode, profile_ix);
 }

 static inline struct net_dim_cq_moder
 net_dim_get_tx_moderation(u8 cq_period_mode, int ix)
 {
 	struct net_dim_cq_moder cq_moder = tx_profile[cq_period_mode][ix];

 	cq_moder.cq_period_mode = cq_period_mode;
 	return cq_moder;
 }

 static inline struct net_dim_cq_moder
 net_dim_get_def_tx_moderation(u8 cq_period_mode)
 {
 	u8 profile_ix = cq_period_mode == NET_DIM_CQ_PERIOD_MODE_START_FROM_CQE ?
 			NET_DIM_DEF_PROFILE_CQE : NET_DIM_DEF_PROFILE_EQE;

 	return net_dim_get_tx_moderation(cq_period_mode, profile_ix);
 }

 static inline bool net_dim_on_top(struct net_dim *dim)
 {
 	switch (dim->tune_state) {
 	case NET_DIM_PARKING_ON_TOP:
 	case NET_DIM_PARKING_TIRED:
 		return true;
 	case NET_DIM_GOING_RIGHT:
 		return (dim->steps_left > 1) && (dim->steps_right == 1);
 	default: /* NET_DIM_GOING_LEFT */
 		return (dim->steps_right > 1) && (dim->steps_left == 1);
 	}
 }

 static inline void net_dim_turn(struct net_dim *dim)
 {
 	switch (dim->tune_state) {
 	case NET_DIM_PARKING_ON_TOP:
 	case NET_DIM_PARKING_TIRED:
 		break;
 	case NET_DIM_GOING_RIGHT:
 		dim->tune_state = NET_DIM_GOING_LEFT;
 		dim->steps_left = 0;
 		break;
 	case NET_DIM_GOING_LEFT:
 		dim->tune_state = NET_DIM_GOING_RIGHT;
 		dim->steps_right = 0;
 		break;
 	}
 }

 static inline int net_dim_step(struct net_dim *dim)
 {
 	if (dim->tired == (NET_DIM_PARAMS_NUM_PROFILES * 2))
 		return NET_DIM_TOO_TIRED;

 	switch (dim->tune_state) {
 	case NET_DIM_PARKING_ON_TOP:
 	case NET_DIM_PARKING_TIRED:
 		break;
 	case NET_DIM_GOING_RIGHT:
 		if (dim->profile_ix == (NET_DIM_PARAMS_NUM_PROFILES - 1))
 			return NET_DIM_ON_EDGE;
 		dim->profile_ix++;
 		dim->steps_right++;
 		break;
 	case NET_DIM_GOING_LEFT:
 		if (dim->profile_ix == 0)
 			return NET_DIM_ON_EDGE;
 		dim->profile_ix--;
 		dim->steps_left++;
 		break;
 	}

 	dim->tired++;
 	return NET_DIM_STEPPED;
 }

 static inline void net_dim_park_on_top(struct net_dim *dim)
 {
 	dim->steps_right  = 0;
 	dim->steps_left   = 0;
 	dim->tired        = 0;
 	dim->tune_state   = NET_DIM_PARKING_ON_TOP;
 }

 static inline void net_dim_park_tired(struct net_dim *dim)
 {
 	dim->steps_right  = 0;
 	dim->steps_left   = 0;
 	dim->tune_state   = NET_DIM_PARKING_TIRED;
 }

 static inline void net_dim_exit_parking(struct net_dim *dim)
 {
 	dim->tune_state = dim->profile_ix ? NET_DIM_GOING_LEFT :
 					  NET_DIM_GOING_RIGHT;
 	net_dim_step(dim);
 }

 #define IS_SIGNIFICANT_DIFF(val, ref) \
 	(((100UL * abs((val) - (ref))) / (ref)) > 10) /* more than 10% difference */

 static inline int net_dim_stats_compare(struct net_dim_stats *curr,
 					struct net_dim_stats *prev)
 {
 	if (!prev->bpms)
 		return curr->bpms ? NET_DIM_STATS_BETTER :
 				    NET_DIM_STATS_SAME;

 	if (IS_SIGNIFICANT_DIFF(curr->bpms, prev->bpms))
 		return (curr->bpms > prev->bpms) ? NET_DIM_STATS_BETTER :
 						   NET_DIM_STATS_WORSE;

 	if (!prev->ppms)
 		return curr->ppms ? NET_DIM_STATS_BETTER :
 				    NET_DIM_STATS_SAME;

 	if (IS_SIGNIFICANT_DIFF(curr->ppms, prev->ppms))
 		return (curr->ppms > prev->ppms) ? NET_DIM_STATS_BETTER :
 						   NET_DIM_STATS_WORSE;

 	if (!prev->epms)
 		return NET_DIM_STATS_SAME;

 	if (IS_SIGNIFICANT_DIFF(curr->epms, prev->epms))
 		return (curr->epms < prev->epms) ? NET_DIM_STATS_BETTER :
 						   NET_DIM_STATS_WORSE;

 	return NET_DIM_STATS_SAME;
 }

 static inline bool net_dim_decision(struct net_dim_stats *curr_stats,
 				    struct net_dim *dim)
 {
 	int prev_state = dim->tune_state;
 	int prev_ix = dim->profile_ix;
 	int stats_res;
 	int step_res;

 	switch (dim->tune_state) {
 	case NET_DIM_PARKING_ON_TOP:
 		stats_res = net_dim_stats_compare(curr_stats, &dim->prev_stats);
 		if (stats_res != NET_DIM_STATS_SAME)
 			net_dim_exit_parking(dim);
 		break;

 	case NET_DIM_PARKING_TIRED:
 		dim->tired--;
 		if (!dim->tired)
 			net_dim_exit_parking(dim);
 		break;

 	case NET_DIM_GOING_RIGHT:
 	case NET_DIM_GOING_LEFT:
 		stats_res = net_dim_stats_compare(curr_stats, &dim->prev_stats);
 		if (stats_res != NET_DIM_STATS_BETTER)
 			net_dim_turn(dim);

 		if (net_dim_on_top(dim)) {
 			net_dim_park_on_top(dim);
 			break;
 		}

 		step_res = net_dim_step(dim);
 		switch (step_res) {
 		case NET_DIM_ON_EDGE:
 			net_dim_park_on_top(dim);
 			break;
 		case NET_DIM_TOO_TIRED:
 			net_dim_park_tired(dim);
 			break;
 		}

 		break;
 	}

 	if ((prev_state      != NET_DIM_PARKING_ON_TOP) ||
 	    (dim->tune_state != NET_DIM_PARKING_ON_TOP))
 		dim->prev_stats = *curr_stats;

 	return dim->profile_ix != prev_ix;
 }

 static inline void net_dim_sample(u16 event_ctr,
 				  u64 packets,
 				  u64 bytes,
 				  struct net_dim_sample *s)
 {
 	s->time	     = ktime_get();
 	s->pkt_ctr   = packets;
 	s->byte_ctr  = bytes;
 	s->event_ctr = event_ctr;
 }

 #define NET_DIM_NEVENTS 64
 #define BIT_GAP(bits, end, start) ((((end) - (start)) + BIT_ULL(bits)) & (BIT_ULL(bits) - 1))

 static inline void net_dim_calc_stats(struct net_dim_sample *start,
 				      struct net_dim_sample *end,
 				      struct net_dim_stats *curr_stats)
 {
 	/* u32 holds up to 71 minutes, should be enough */
 	u32 delta_us = ktime_us_delta(end->time, start->time);
 	u32 npkts = BIT_GAP(BITS_PER_TYPE(u32), end->pkt_ctr, start->pkt_ctr);
 	u32 nbytes = BIT_GAP(BITS_PER_TYPE(u32), end->byte_ctr,
 			     start->byte_ctr);

 	if (!delta_us)
 		return;

 	curr_stats->ppms = DIV_ROUND_UP(npkts * USEC_PER_MSEC, delta_us);
 	curr_stats->bpms = DIV_ROUND_UP(nbytes * USEC_PER_MSEC, delta_us);
 	curr_stats->epms = DIV_ROUND_UP(NET_DIM_NEVENTS * USEC_PER_MSEC,
 					delta_us);
 }

 static inline void net_dim(struct net_dim *dim,
 			   struct net_dim_sample end_sample)
 {
 	struct net_dim_stats curr_stats;
 	u16 nevents;

 	switch (dim->state) {
 	case NET_DIM_MEASURE_IN_PROGRESS:
 		nevents = BIT_GAP(BITS_PER_TYPE(u16),
 				  end_sample.event_ctr,
 				  dim->start_sample.event_ctr);
 		if (nevents < NET_DIM_NEVENTS)
 			break;
 		net_dim_calc_stats(&dim->start_sample, &end_sample,
 				   &curr_stats);
 		if (net_dim_decision(&curr_stats, dim)) {
 			dim->state = NET_DIM_APPLY_NEW_PROFILE;
 			schedule_work(&dim->work);
 			break;
 		}
 		/* fall through */
 	case NET_DIM_START_MEASURE:
 		net_dim_sample(end_sample.event_ctr, end_sample.pkt_ctr, end_sample.byte_ctr,
 			       &dim->start_sample);
 		dim->state = NET_DIM_MEASURE_IN_PROGRESS;
 		break;
 	case NET_DIM_APPLY_NEW_PROFILE:
 		break;
 	}
 }

 #endif /* NET_DIM_H */
	/*
	* Copyright (c) 2016, Mellanox Technologies. All rights reserved.
	* Copyright (c) 2017-2018, Broadcom Limited. All rights reserved.
	*
	* This software is available to you under a choice of one of two
	* licenses. You may choose to be licensed under the terms of the GNU
	* General Public License (GPL) Version 2, available from the file
	* COPYING in the main directory of this source tree, or the
	* OpenIB.org BSD license below:
	*
	* Redistribution and use in source and binary forms, with or
	* without modification, are permitted provided that the following
	* conditions are met:
	*
	* - Redistributions of source code must retain the above
	* copyright notice, this list of conditions and the following
	* disclaimer.
	*
	* - Redistributions in binary form must reproduce the above
	* copyright notice, this list of conditions and the following
	* disclaimer in the documentation and/or other materials
	* provided with the distribution.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
	* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
	* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
	* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
	* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
	* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
	* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
	* SOFTWARE.
	*/

	#ifndef NET_DIM_H
	#define NET_DIM_H

	#include <linux/module.h>

	struct net_dim_cq_moder {
	u16 usec;
	u16 pkts;
	u8 cq_period_mode;
	};

	struct net_dim_sample {
	ktime_t time;
	u32 pkt_ctr;
	u32 byte_ctr;
	u16 event_ctr;
	};

	struct net_dim_stats {
	int ppms; /* packets per msec */
	int bpms; /* bytes per msec */
	int epms; /* events per msec */
	};

	struct net_dim { /* Adaptive Moderation */
	u8 state;
	struct net_dim_stats prev_stats;
	struct net_dim_sample start_sample;
	struct work_struct work;
	u8 profile_ix;
	u8 mode;
	u8 tune_state;
	u8 steps_right;
	u8 steps_left;
	u8 tired;
	};

	enum {
	NET_DIM_CQ_PERIOD_MODE_START_FROM_EQE = 0x0,
	NET_DIM_CQ_PERIOD_MODE_START_FROM_CQE = 0x1,
	NET_DIM_CQ_PERIOD_NUM_MODES
	};

	/* Adaptive moderation logic */
	enum {
	NET_DIM_START_MEASURE,
	NET_DIM_MEASURE_IN_PROGRESS,
	NET_DIM_APPLY_NEW_PROFILE,
	};

	enum {
	NET_DIM_PARKING_ON_TOP,
	NET_DIM_PARKING_TIRED,
	NET_DIM_GOING_RIGHT,
	NET_DIM_GOING_LEFT,
	};

	enum {
	NET_DIM_STATS_WORSE,
	NET_DIM_STATS_SAME,
	NET_DIM_STATS_BETTER,
	};

	enum {
	NET_DIM_STEPPED,
	NET_DIM_TOO_TIRED,
	NET_DIM_ON_EDGE,
	};

	#define NET_DIM_PARAMS_NUM_PROFILES 5
	/* Adaptive moderation profiles */
	#define NET_DIM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE 256
	#define NET_DIM_DEFAULT_TX_CQ_MODERATION_PKTS_FROM_EQE 128
	#define NET_DIM_DEF_PROFILE_CQE 1
	#define NET_DIM_DEF_PROFILE_EQE 1

	/* All profiles sizes must be NET_PARAMS_DIM_NUM_PROFILES */
	#define NET_DIM_RX_EQE_PROFILES { \
	{1, NET_DIM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
	{8, NET_DIM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
	{64, NET_DIM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
	{128, NET_DIM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
	{256, NET_DIM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
	}

	#define NET_DIM_RX_CQE_PROFILES { \
	{2, 256}, \
	{8, 128}, \
	{16, 64}, \
	{32, 64}, \
	{64, 64} \
	}

	#define NET_DIM_TX_EQE_PROFILES { \
	{1, NET_DIM_DEFAULT_TX_CQ_MODERATION_PKTS_FROM_EQE}, \
	{8, NET_DIM_DEFAULT_TX_CQ_MODERATION_PKTS_FROM_EQE}, \
	{32, NET_DIM_DEFAULT_TX_CQ_MODERATION_PKTS_FROM_EQE}, \
	{64, NET_DIM_DEFAULT_TX_CQ_MODERATION_PKTS_FROM_EQE}, \
	{128, NET_DIM_DEFAULT_TX_CQ_MODERATION_PKTS_FROM_EQE} \
	}

	#define NET_DIM_TX_CQE_PROFILES { \
	{5, 128}, \
	{8, 64}, \
	{16, 32}, \
	{32, 32}, \
	{64, 32} \
	}

	static const struct net_dim_cq_moder
	rx_profile[NET_DIM_CQ_PERIOD_NUM_MODES][NET_DIM_PARAMS_NUM_PROFILES] = {
	NET_DIM_RX_EQE_PROFILES,
	NET_DIM_RX_CQE_PROFILES,
	};

	static const struct net_dim_cq_moder
	tx_profile[NET_DIM_CQ_PERIOD_NUM_MODES][NET_DIM_PARAMS_NUM_PROFILES] = {
	NET_DIM_TX_EQE_PROFILES,
	NET_DIM_TX_CQE_PROFILES,
	};

	static inline struct net_dim_cq_moder
	net_dim_get_rx_moderation(u8 cq_period_mode, int ix)
	{
	struct net_dim_cq_moder cq_moder = rx_profile[cq_period_mode][ix];

	cq_moder.cq_period_mode = cq_period_mode;
	return cq_moder;
	}

	static inline struct net_dim_cq_moder
	net_dim_get_def_rx_moderation(u8 cq_period_mode)
	{
	u8 profile_ix = cq_period_mode == NET_DIM_CQ_PERIOD_MODE_START_FROM_CQE ?
	NET_DIM_DEF_PROFILE_CQE : NET_DIM_DEF_PROFILE_EQE;

	return net_dim_get_rx_moderation(cq_period_mode, profile_ix);
	}

	static inline struct net_dim_cq_moder
	net_dim_get_tx_moderation(u8 cq_period_mode, int ix)
	{
	struct net_dim_cq_moder cq_moder = tx_profile[cq_period_mode][ix];

	cq_moder.cq_period_mode = cq_period_mode;
	return cq_moder;
	}

	static inline struct net_dim_cq_moder
	net_dim_get_def_tx_moderation(u8 cq_period_mode)
	{
	u8 profile_ix = cq_period_mode == NET_DIM_CQ_PERIOD_MODE_START_FROM_CQE ?
	NET_DIM_DEF_PROFILE_CQE : NET_DIM_DEF_PROFILE_EQE;

	return net_dim_get_tx_moderation(cq_period_mode, profile_ix);
	}

	static inline bool net_dim_on_top(struct net_dim *dim)
	{
	switch (dim->tune_state) {
	case NET_DIM_PARKING_ON_TOP:
	case NET_DIM_PARKING_TIRED:
	return true;
	case NET_DIM_GOING_RIGHT:
	return (dim->steps_left > 1) && (dim->steps_right == 1);
	default: /* NET_DIM_GOING_LEFT */
	return (dim->steps_right > 1) && (dim->steps_left == 1);
	}
	}

	static inline void net_dim_turn(struct net_dim *dim)
	{
	switch (dim->tune_state) {
	case NET_DIM_PARKING_ON_TOP:
	case NET_DIM_PARKING_TIRED:
	break;
	case NET_DIM_GOING_RIGHT:
	dim->tune_state = NET_DIM_GOING_LEFT;
	dim->steps_left = 0;
	break;
	case NET_DIM_GOING_LEFT:
	dim->tune_state = NET_DIM_GOING_RIGHT;
	dim->steps_right = 0;
	break;
	}
	}

	static inline int net_dim_step(struct net_dim *dim)
	{
	if (dim->tired == (NET_DIM_PARAMS_NUM_PROFILES * 2))
	return NET_DIM_TOO_TIRED;

	switch (dim->tune_state) {
	case NET_DIM_PARKING_ON_TOP:
	case NET_DIM_PARKING_TIRED:
	break;
	case NET_DIM_GOING_RIGHT:
	if (dim->profile_ix == (NET_DIM_PARAMS_NUM_PROFILES - 1))
	return NET_DIM_ON_EDGE;
	dim->profile_ix++;
	dim->steps_right++;
	break;
	case NET_DIM_GOING_LEFT:
	if (dim->profile_ix == 0)
	return NET_DIM_ON_EDGE;
	dim->profile_ix--;
	dim->steps_left++;
	break;
	}

	dim->tired++;
	return NET_DIM_STEPPED;
	}

	static inline void net_dim_park_on_top(struct net_dim *dim)
	{
	dim->steps_right = 0;
	dim->steps_left = 0;
	dim->tired = 0;
	dim->tune_state = NET_DIM_PARKING_ON_TOP;
	}

	static inline void net_dim_park_tired(struct net_dim *dim)
	{
	dim->steps_right = 0;
	dim->steps_left = 0;
	dim->tune_state = NET_DIM_PARKING_TIRED;
	}

	static inline void net_dim_exit_parking(struct net_dim *dim)
	{
	dim->tune_state = dim->profile_ix ? NET_DIM_GOING_LEFT :
	NET_DIM_GOING_RIGHT;
	net_dim_step(dim);
	}

	#define IS_SIGNIFICANT_DIFF(val, ref) \
	(((100UL * abs((val) - (ref))) / (ref)) > 10) /* more than 10% difference */

	static inline int net_dim_stats_compare(struct net_dim_stats *curr,
	struct net_dim_stats *prev)
	{
	if (!prev->bpms)
	return curr->bpms ? NET_DIM_STATS_BETTER :
	NET_DIM_STATS_SAME;

	if (IS_SIGNIFICANT_DIFF(curr->bpms, prev->bpms))
	return (curr->bpms > prev->bpms) ? NET_DIM_STATS_BETTER :
	NET_DIM_STATS_WORSE;

	if (!prev->ppms)
	return curr->ppms ? NET_DIM_STATS_BETTER :
	NET_DIM_STATS_SAME;

	if (IS_SIGNIFICANT_DIFF(curr->ppms, prev->ppms))
	return (curr->ppms > prev->ppms) ? NET_DIM_STATS_BETTER :
	NET_DIM_STATS_WORSE;

	if (!prev->epms)
	return NET_DIM_STATS_SAME;

	if (IS_SIGNIFICANT_DIFF(curr->epms, prev->epms))
	return (curr->epms < prev->epms) ? NET_DIM_STATS_BETTER :
	NET_DIM_STATS_WORSE;

	return NET_DIM_STATS_SAME;
	}

	static inline bool net_dim_decision(struct net_dim_stats *curr_stats,
	struct net_dim *dim)
	{
	int prev_state = dim->tune_state;
	int prev_ix = dim->profile_ix;
	int stats_res;
	int step_res;

	switch (dim->tune_state) {
	case NET_DIM_PARKING_ON_TOP:
	stats_res = net_dim_stats_compare(curr_stats, &dim->prev_stats);
	if (stats_res != NET_DIM_STATS_SAME)
	net_dim_exit_parking(dim);
	break;

	case NET_DIM_PARKING_TIRED:
	dim->tired--;
	if (!dim->tired)
	net_dim_exit_parking(dim);
	break;

	case NET_DIM_GOING_RIGHT:
	case NET_DIM_GOING_LEFT:
	stats_res = net_dim_stats_compare(curr_stats, &dim->prev_stats);
	if (stats_res != NET_DIM_STATS_BETTER)
	net_dim_turn(dim);

	if (net_dim_on_top(dim)) {
	net_dim_park_on_top(dim);
	break;
	}

	step_res = net_dim_step(dim);
	switch (step_res) {
	case NET_DIM_ON_EDGE:
	net_dim_park_on_top(dim);
	break;
	case NET_DIM_TOO_TIRED:
	net_dim_park_tired(dim);
	break;
	}

	break;
	}

	if ((prev_state != NET_DIM_PARKING_ON_TOP) \|\|
	(dim->tune_state != NET_DIM_PARKING_ON_TOP))
	dim->prev_stats = *curr_stats;

	return dim->profile_ix != prev_ix;
	}

	static inline void net_dim_sample(u16 event_ctr,
	u64 packets,
	u64 bytes,
	struct net_dim_sample *s)
	{
	s->time = ktime_get();
	s->pkt_ctr = packets;
	s->byte_ctr = bytes;
	s->event_ctr = event_ctr;
	}

	#define NET_DIM_NEVENTS 64
	#define BIT_GAP(bits, end, start) ((((end) - (start)) + BIT_ULL(bits)) & (BIT_ULL(bits) - 1))

	static inline void net_dim_calc_stats(struct net_dim_sample *start,
	struct net_dim_sample *end,
	struct net_dim_stats *curr_stats)
	{
	/* u32 holds up to 71 minutes, should be enough */
	u32 delta_us = ktime_us_delta(end->time, start->time);
	u32 npkts = BIT_GAP(BITS_PER_TYPE(u32), end->pkt_ctr, start->pkt_ctr);
	u32 nbytes = BIT_GAP(BITS_PER_TYPE(u32), end->byte_ctr,
	start->byte_ctr);

	if (!delta_us)
	return;

	curr_stats->ppms = DIV_ROUND_UP(npkts * USEC_PER_MSEC, delta_us);
	curr_stats->bpms = DIV_ROUND_UP(nbytes * USEC_PER_MSEC, delta_us);
	curr_stats->epms = DIV_ROUND_UP(NET_DIM_NEVENTS * USEC_PER_MSEC,
	delta_us);
	}

	static inline void net_dim(struct net_dim *dim,
	struct net_dim_sample end_sample)
	{
	struct net_dim_stats curr_stats;
	u16 nevents;

	switch (dim->state) {
	case NET_DIM_MEASURE_IN_PROGRESS:
	nevents = BIT_GAP(BITS_PER_TYPE(u16),
	end_sample.event_ctr,
	dim->start_sample.event_ctr);
	if (nevents < NET_DIM_NEVENTS)
	break;
	net_dim_calc_stats(&dim->start_sample, &end_sample,
	&curr_stats);
	if (net_dim_decision(&curr_stats, dim)) {
	dim->state = NET_DIM_APPLY_NEW_PROFILE;
	schedule_work(&dim->work);
	break;
	}
	/* fall through */
	case NET_DIM_START_MEASURE:
	net_dim_sample(end_sample.event_ctr, end_sample.pkt_ctr, end_sample.byte_ctr,
	&dim->start_sample);
	dim->state = NET_DIM_MEASURE_IN_PROGRESS;
	break;
	case NET_DIM_APPLY_NEW_PROFILE:
	break;
	}
	}

	#endif /* NET_DIM_H */