drivers/net/ethernet/mellanox/mlx5/core/en_rx_am.c - arm/linux - Git at Google

 /*
  * Copyright (c) 2016, Mellanox Technologies. 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.
  */

 #include "en.h"

 /* Adaptive moderation profiles */
 #define MLX5E_AM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE 256
 #define MLX5E_RX_AM_DEF_PROFILE_CQE 1
 #define MLX5E_RX_AM_DEF_PROFILE_EQE 1
 #define MLX5E_PARAMS_AM_NUM_PROFILES 5

 /* All profiles sizes must be MLX5E_PARAMS_AM_NUM_PROFILES */
 #define MLX5_AM_EQE_PROFILES { \
 	{1,   MLX5E_AM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
 	{8,   MLX5E_AM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
 	{64,  MLX5E_AM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
 	{128, MLX5E_AM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
 	{256, MLX5E_AM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
 }

 #define MLX5_AM_CQE_PROFILES { \
 	{2,  256},             \
 	{8,  128},             \
 	{16, 64},              \
 	{32, 64},              \
 	{64, 64}               \
 }

 static const struct mlx5e_cq_moder
 profile[MLX5_CQ_PERIOD_NUM_MODES][MLX5E_PARAMS_AM_NUM_PROFILES] = {
 	MLX5_AM_EQE_PROFILES,
 	MLX5_AM_CQE_PROFILES,
 };

 static inline struct mlx5e_cq_moder mlx5e_am_get_profile(u8 cq_period_mode, int ix)
 {
 	return profile[cq_period_mode][ix];
 }

 struct mlx5e_cq_moder mlx5e_am_get_def_profile(u8 rx_cq_period_mode)
 {
 	int default_profile_ix;

 	if (rx_cq_period_mode == MLX5_CQ_PERIOD_MODE_START_FROM_CQE)
 		default_profile_ix = MLX5E_RX_AM_DEF_PROFILE_CQE;
 	else /* MLX5_CQ_PERIOD_MODE_START_FROM_EQE */
 		default_profile_ix = MLX5E_RX_AM_DEF_PROFILE_EQE;

 	return profile[rx_cq_period_mode][default_profile_ix];
 }

 /* Adaptive moderation logic */
 enum {
 	MLX5E_AM_START_MEASURE,
 	MLX5E_AM_MEASURE_IN_PROGRESS,
 	MLX5E_AM_APPLY_NEW_PROFILE,
 };

 enum {
 	MLX5E_AM_PARKING_ON_TOP,
 	MLX5E_AM_PARKING_TIRED,
 	MLX5E_AM_GOING_RIGHT,
 	MLX5E_AM_GOING_LEFT,
 };

 enum {
 	MLX5E_AM_STATS_WORSE,
 	MLX5E_AM_STATS_SAME,
 	MLX5E_AM_STATS_BETTER,
 };

 enum {
 	MLX5E_AM_STEPPED,
 	MLX5E_AM_TOO_TIRED,
 	MLX5E_AM_ON_EDGE,
 };

 static bool mlx5e_am_on_top(struct mlx5e_rx_am *am)
 {
 	switch (am->tune_state) {
 	case MLX5E_AM_PARKING_ON_TOP:
 	case MLX5E_AM_PARKING_TIRED:
 		return true;
 	case MLX5E_AM_GOING_RIGHT:
 		return (am->steps_left > 1) && (am->steps_right == 1);
 	default: /* MLX5E_AM_GOING_LEFT */
 		return (am->steps_right > 1) && (am->steps_left == 1);
 	}
 }

 static void mlx5e_am_turn(struct mlx5e_rx_am *am)
 {
 	switch (am->tune_state) {
 	case MLX5E_AM_PARKING_ON_TOP:
 	case MLX5E_AM_PARKING_TIRED:
 		break;
 	case MLX5E_AM_GOING_RIGHT:
 		am->tune_state = MLX5E_AM_GOING_LEFT;
 		am->steps_left = 0;
 		break;
 	case MLX5E_AM_GOING_LEFT:
 		am->tune_state = MLX5E_AM_GOING_RIGHT;
 		am->steps_right = 0;
 		break;
 	}
 }

 static int mlx5e_am_step(struct mlx5e_rx_am *am)
 {
 	if (am->tired == (MLX5E_PARAMS_AM_NUM_PROFILES * 2))
 		return MLX5E_AM_TOO_TIRED;

 	switch (am->tune_state) {
 	case MLX5E_AM_PARKING_ON_TOP:
 	case MLX5E_AM_PARKING_TIRED:
 		break;
 	case MLX5E_AM_GOING_RIGHT:
 		if (am->profile_ix == (MLX5E_PARAMS_AM_NUM_PROFILES - 1))
 			return MLX5E_AM_ON_EDGE;
 		am->profile_ix++;
 		am->steps_right++;
 		break;
 	case MLX5E_AM_GOING_LEFT:
 		if (am->profile_ix == 0)
 			return MLX5E_AM_ON_EDGE;
 		am->profile_ix--;
 		am->steps_left++;
 		break;
 	}

 	am->tired++;
 	return MLX5E_AM_STEPPED;
 }

 static void mlx5e_am_park_on_top(struct mlx5e_rx_am *am)
 {
 	am->steps_right  = 0;
 	am->steps_left   = 0;
 	am->tired        = 0;
 	am->tune_state   = MLX5E_AM_PARKING_ON_TOP;
 }

 static void mlx5e_am_park_tired(struct mlx5e_rx_am *am)
 {
 	am->steps_right  = 0;
 	am->steps_left   = 0;
 	am->tune_state   = MLX5E_AM_PARKING_TIRED;
 }

 static void mlx5e_am_exit_parking(struct mlx5e_rx_am *am)
 {
 	am->tune_state = am->profile_ix ? MLX5E_AM_GOING_LEFT :
 					  MLX5E_AM_GOING_RIGHT;
 	mlx5e_am_step(am);
 }

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

 static int mlx5e_am_stats_compare(struct mlx5e_rx_am_stats *curr,
 				  struct mlx5e_rx_am_stats *prev)
 {
 	if (!prev->bpms)
 		return curr->bpms ? MLX5E_AM_STATS_BETTER :
 				    MLX5E_AM_STATS_SAME;

 	if (IS_SIGNIFICANT_DIFF(curr->bpms, prev->bpms))
 		return (curr->bpms > prev->bpms) ? MLX5E_AM_STATS_BETTER :
 						   MLX5E_AM_STATS_WORSE;

 	if (IS_SIGNIFICANT_DIFF(curr->ppms, prev->ppms))
 		return (curr->ppms > prev->ppms) ? MLX5E_AM_STATS_BETTER :
 						   MLX5E_AM_STATS_WORSE;

 	if (IS_SIGNIFICANT_DIFF(curr->epms, prev->epms))
 		return (curr->epms < prev->epms) ? MLX5E_AM_STATS_BETTER :
 						   MLX5E_AM_STATS_WORSE;

 	return MLX5E_AM_STATS_SAME;
 }

 static bool mlx5e_am_decision(struct mlx5e_rx_am_stats *curr_stats,
 			      struct mlx5e_rx_am *am)
 {
 	int prev_state = am->tune_state;
 	int prev_ix = am->profile_ix;
 	int stats_res;
 	int step_res;

 	switch (am->tune_state) {
 	case MLX5E_AM_PARKING_ON_TOP:
 		stats_res = mlx5e_am_stats_compare(curr_stats, &am->prev_stats);
 		if (stats_res != MLX5E_AM_STATS_SAME)
 			mlx5e_am_exit_parking(am);
 		break;

 	case MLX5E_AM_PARKING_TIRED:
 		am->tired--;
 		if (!am->tired)
 			mlx5e_am_exit_parking(am);
 		break;

 	case MLX5E_AM_GOING_RIGHT:
 	case MLX5E_AM_GOING_LEFT:
 		stats_res = mlx5e_am_stats_compare(curr_stats, &am->prev_stats);
 		if (stats_res != MLX5E_AM_STATS_BETTER)
 			mlx5e_am_turn(am);

 		if (mlx5e_am_on_top(am)) {
 			mlx5e_am_park_on_top(am);
 			break;
 		}

 		step_res = mlx5e_am_step(am);
 		switch (step_res) {
 		case MLX5E_AM_ON_EDGE:
 			mlx5e_am_park_on_top(am);
 			break;
 		case MLX5E_AM_TOO_TIRED:
 			mlx5e_am_park_tired(am);
 			break;
 		}

 		break;
 	}

 	if ((prev_state     != MLX5E_AM_PARKING_ON_TOP) ||
 	    (am->tune_state != MLX5E_AM_PARKING_ON_TOP))
 		am->prev_stats = *curr_stats;

 	return am->profile_ix != prev_ix;
 }

 static void mlx5e_am_sample(struct mlx5e_rq *rq,
 			    struct mlx5e_rx_am_sample *s)
 {
 	s->time	     = ktime_get();
 	s->pkt_ctr   = rq->stats.packets;
 	s->byte_ctr  = rq->stats.bytes;
 	s->event_ctr = rq->cq.event_ctr;
 }

 #define MLX5E_AM_NEVENTS 64
 #define BITS_PER_TYPE(type) (sizeof(type) * BITS_PER_BYTE)
 #define BIT_GAP(bits, end, start) ((((end) - (start)) + BIT_ULL(bits)) & (BIT_ULL(bits) - 1))

 static void mlx5e_am_calc_stats(struct mlx5e_rx_am_sample *start,
 				struct mlx5e_rx_am_sample *end,
 				struct mlx5e_rx_am_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(MLX5E_AM_NEVENTS * USEC_PER_MSEC,
 					delta_us);
 }

 void mlx5e_rx_am_work(struct work_struct *work)
 {
 	struct mlx5e_rx_am *am = container_of(work, struct mlx5e_rx_am,
 					      work);
 	struct mlx5e_rq *rq = container_of(am, struct mlx5e_rq, am);
 	struct mlx5e_cq_moder cur_profile = profile[am->mode][am->profile_ix];

 	mlx5_core_modify_cq_moderation(rq->mdev, &rq->cq.mcq,
 				       cur_profile.usec, cur_profile.pkts);

 	am->state = MLX5E_AM_START_MEASURE;
 }

 void mlx5e_rx_am(struct mlx5e_rq *rq)
 {
 	struct mlx5e_rx_am *am = &rq->am;
 	struct mlx5e_rx_am_sample end_sample;
 	struct mlx5e_rx_am_stats curr_stats;
 	u16 nevents;

 	switch (am->state) {
 	case MLX5E_AM_MEASURE_IN_PROGRESS:
 		nevents = BIT_GAP(BITS_PER_TYPE(u16), rq->cq.event_ctr,
 				  am->start_sample.event_ctr);
 		if (nevents < MLX5E_AM_NEVENTS)
 			break;
 		mlx5e_am_sample(rq, &end_sample);
 		mlx5e_am_calc_stats(&am->start_sample, &end_sample,
 				    &curr_stats);
 		if (mlx5e_am_decision(&curr_stats, am)) {
 			am->state = MLX5E_AM_APPLY_NEW_PROFILE;
 			schedule_work(&am->work);
 			break;
 		}
 		/* fall through */
 	case MLX5E_AM_START_MEASURE:
 		mlx5e_am_sample(rq, &am->start_sample);
 		am->state = MLX5E_AM_MEASURE_IN_PROGRESS;
 		break;
 	case MLX5E_AM_APPLY_NEW_PROFILE:
 		break;
 	}
 }
	/*
	* Copyright (c) 2016, Mellanox Technologies. 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.
	*/

	#include "en.h"

	/* Adaptive moderation profiles */
	#define MLX5E_AM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE 256
	#define MLX5E_RX_AM_DEF_PROFILE_CQE 1
	#define MLX5E_RX_AM_DEF_PROFILE_EQE 1
	#define MLX5E_PARAMS_AM_NUM_PROFILES 5

	/* All profiles sizes must be MLX5E_PARAMS_AM_NUM_PROFILES */
	#define MLX5_AM_EQE_PROFILES { \
	{1, MLX5E_AM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
	{8, MLX5E_AM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
	{64, MLX5E_AM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
	{128, MLX5E_AM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
	{256, MLX5E_AM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
	}

	#define MLX5_AM_CQE_PROFILES { \
	{2, 256}, \
	{8, 128}, \
	{16, 64}, \
	{32, 64}, \
	{64, 64} \
	}

	static const struct mlx5e_cq_moder
	profile[MLX5_CQ_PERIOD_NUM_MODES][MLX5E_PARAMS_AM_NUM_PROFILES] = {
	MLX5_AM_EQE_PROFILES,
	MLX5_AM_CQE_PROFILES,
	};

	static inline struct mlx5e_cq_moder mlx5e_am_get_profile(u8 cq_period_mode, int ix)
	{
	return profile[cq_period_mode][ix];
	}

	struct mlx5e_cq_moder mlx5e_am_get_def_profile(u8 rx_cq_period_mode)
	{
	int default_profile_ix;

	if (rx_cq_period_mode == MLX5_CQ_PERIOD_MODE_START_FROM_CQE)
	default_profile_ix = MLX5E_RX_AM_DEF_PROFILE_CQE;
	else /* MLX5_CQ_PERIOD_MODE_START_FROM_EQE */
	default_profile_ix = MLX5E_RX_AM_DEF_PROFILE_EQE;

	return profile[rx_cq_period_mode][default_profile_ix];
	}

	/* Adaptive moderation logic */
	enum {
	MLX5E_AM_START_MEASURE,
	MLX5E_AM_MEASURE_IN_PROGRESS,
	MLX5E_AM_APPLY_NEW_PROFILE,
	};

	enum {
	MLX5E_AM_PARKING_ON_TOP,
	MLX5E_AM_PARKING_TIRED,
	MLX5E_AM_GOING_RIGHT,
	MLX5E_AM_GOING_LEFT,
	};

	enum {
	MLX5E_AM_STATS_WORSE,
	MLX5E_AM_STATS_SAME,
	MLX5E_AM_STATS_BETTER,
	};

	enum {
	MLX5E_AM_STEPPED,
	MLX5E_AM_TOO_TIRED,
	MLX5E_AM_ON_EDGE,
	};

	static bool mlx5e_am_on_top(struct mlx5e_rx_am *am)
	{
	switch (am->tune_state) {
	case MLX5E_AM_PARKING_ON_TOP:
	case MLX5E_AM_PARKING_TIRED:
	return true;
	case MLX5E_AM_GOING_RIGHT:
	return (am->steps_left > 1) && (am->steps_right == 1);
	default: /* MLX5E_AM_GOING_LEFT */
	return (am->steps_right > 1) && (am->steps_left == 1);
	}
	}

	static void mlx5e_am_turn(struct mlx5e_rx_am *am)
	{
	switch (am->tune_state) {
	case MLX5E_AM_PARKING_ON_TOP:
	case MLX5E_AM_PARKING_TIRED:
	break;
	case MLX5E_AM_GOING_RIGHT:
	am->tune_state = MLX5E_AM_GOING_LEFT;
	am->steps_left = 0;
	break;
	case MLX5E_AM_GOING_LEFT:
	am->tune_state = MLX5E_AM_GOING_RIGHT;
	am->steps_right = 0;
	break;
	}
	}

	static int mlx5e_am_step(struct mlx5e_rx_am *am)
	{
	if (am->tired == (MLX5E_PARAMS_AM_NUM_PROFILES * 2))
	return MLX5E_AM_TOO_TIRED;

	switch (am->tune_state) {
	case MLX5E_AM_PARKING_ON_TOP:
	case MLX5E_AM_PARKING_TIRED:
	break;
	case MLX5E_AM_GOING_RIGHT:
	if (am->profile_ix == (MLX5E_PARAMS_AM_NUM_PROFILES - 1))
	return MLX5E_AM_ON_EDGE;
	am->profile_ix++;
	am->steps_right++;
	break;
	case MLX5E_AM_GOING_LEFT:
	if (am->profile_ix == 0)
	return MLX5E_AM_ON_EDGE;
	am->profile_ix--;
	am->steps_left++;
	break;
	}

	am->tired++;
	return MLX5E_AM_STEPPED;
	}

	static void mlx5e_am_park_on_top(struct mlx5e_rx_am *am)
	{
	am->steps_right = 0;
	am->steps_left = 0;
	am->tired = 0;
	am->tune_state = MLX5E_AM_PARKING_ON_TOP;
	}

	static void mlx5e_am_park_tired(struct mlx5e_rx_am *am)
	{
	am->steps_right = 0;
	am->steps_left = 0;
	am->tune_state = MLX5E_AM_PARKING_TIRED;
	}

	static void mlx5e_am_exit_parking(struct mlx5e_rx_am *am)
	{
	am->tune_state = am->profile_ix ? MLX5E_AM_GOING_LEFT :
	MLX5E_AM_GOING_RIGHT;
	mlx5e_am_step(am);
	}

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

	static int mlx5e_am_stats_compare(struct mlx5e_rx_am_stats *curr,
	struct mlx5e_rx_am_stats *prev)
	{
	if (!prev->bpms)
	return curr->bpms ? MLX5E_AM_STATS_BETTER :
	MLX5E_AM_STATS_SAME;

	if (IS_SIGNIFICANT_DIFF(curr->bpms, prev->bpms))
	return (curr->bpms > prev->bpms) ? MLX5E_AM_STATS_BETTER :
	MLX5E_AM_STATS_WORSE;

	if (IS_SIGNIFICANT_DIFF(curr->ppms, prev->ppms))
	return (curr->ppms > prev->ppms) ? MLX5E_AM_STATS_BETTER :
	MLX5E_AM_STATS_WORSE;

	if (IS_SIGNIFICANT_DIFF(curr->epms, prev->epms))
	return (curr->epms < prev->epms) ? MLX5E_AM_STATS_BETTER :
	MLX5E_AM_STATS_WORSE;

	return MLX5E_AM_STATS_SAME;
	}

	static bool mlx5e_am_decision(struct mlx5e_rx_am_stats *curr_stats,
	struct mlx5e_rx_am *am)
	{
	int prev_state = am->tune_state;
	int prev_ix = am->profile_ix;
	int stats_res;
	int step_res;

	switch (am->tune_state) {
	case MLX5E_AM_PARKING_ON_TOP:
	stats_res = mlx5e_am_stats_compare(curr_stats, &am->prev_stats);
	if (stats_res != MLX5E_AM_STATS_SAME)
	mlx5e_am_exit_parking(am);
	break;

	case MLX5E_AM_PARKING_TIRED:
	am->tired--;
	if (!am->tired)
	mlx5e_am_exit_parking(am);
	break;

	case MLX5E_AM_GOING_RIGHT:
	case MLX5E_AM_GOING_LEFT:
	stats_res = mlx5e_am_stats_compare(curr_stats, &am->prev_stats);
	if (stats_res != MLX5E_AM_STATS_BETTER)
	mlx5e_am_turn(am);

	if (mlx5e_am_on_top(am)) {
	mlx5e_am_park_on_top(am);
	break;
	}

	step_res = mlx5e_am_step(am);
	switch (step_res) {
	case MLX5E_AM_ON_EDGE:
	mlx5e_am_park_on_top(am);
	break;
	case MLX5E_AM_TOO_TIRED:
	mlx5e_am_park_tired(am);
	break;
	}

	break;
	}

	if ((prev_state != MLX5E_AM_PARKING_ON_TOP) \|\|
	(am->tune_state != MLX5E_AM_PARKING_ON_TOP))
	am->prev_stats = *curr_stats;

	return am->profile_ix != prev_ix;
	}

	static void mlx5e_am_sample(struct mlx5e_rq *rq,
	struct mlx5e_rx_am_sample *s)
	{
	s->time = ktime_get();
	s->pkt_ctr = rq->stats.packets;
	s->byte_ctr = rq->stats.bytes;
	s->event_ctr = rq->cq.event_ctr;
	}

	#define MLX5E_AM_NEVENTS 64
	#define BITS_PER_TYPE(type) (sizeof(type) * BITS_PER_BYTE)
	#define BIT_GAP(bits, end, start) ((((end) - (start)) + BIT_ULL(bits)) & (BIT_ULL(bits) - 1))

	static void mlx5e_am_calc_stats(struct mlx5e_rx_am_sample *start,
	struct mlx5e_rx_am_sample *end,
	struct mlx5e_rx_am_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(MLX5E_AM_NEVENTS * USEC_PER_MSEC,
	delta_us);
	}

	void mlx5e_rx_am_work(struct work_struct *work)
	{
	struct mlx5e_rx_am *am = container_of(work, struct mlx5e_rx_am,
	work);
	struct mlx5e_rq *rq = container_of(am, struct mlx5e_rq, am);
	struct mlx5e_cq_moder cur_profile = profile[am->mode][am->profile_ix];

	mlx5_core_modify_cq_moderation(rq->mdev, &rq->cq.mcq,
	cur_profile.usec, cur_profile.pkts);

	am->state = MLX5E_AM_START_MEASURE;
	}

	void mlx5e_rx_am(struct mlx5e_rq *rq)
	{
	struct mlx5e_rx_am *am = &rq->am;
	struct mlx5e_rx_am_sample end_sample;
	struct mlx5e_rx_am_stats curr_stats;
	u16 nevents;

	switch (am->state) {
	case MLX5E_AM_MEASURE_IN_PROGRESS:
	nevents = BIT_GAP(BITS_PER_TYPE(u16), rq->cq.event_ctr,
	am->start_sample.event_ctr);
	if (nevents < MLX5E_AM_NEVENTS)
	break;
	mlx5e_am_sample(rq, &end_sample);
	mlx5e_am_calc_stats(&am->start_sample, &end_sample,
	&curr_stats);
	if (mlx5e_am_decision(&curr_stats, am)) {
	am->state = MLX5E_AM_APPLY_NEW_PROFILE;
	schedule_work(&am->work);
	break;
	}
	/* fall through */
	case MLX5E_AM_START_MEASURE:
	mlx5e_am_sample(rq, &am->start_sample);
	am->state = MLX5E_AM_MEASURE_IN_PROGRESS;
	break;
	case MLX5E_AM_APPLY_NEW_PROFILE:
	break;
	}
	}