net/mlx5e: Move dynamic interrupt coalescing code to include/linux

This move allows drivers to add private structure elements to track the
number of packets, bytes, and interrupts events per ring.  A driver
also defines a workqueue handler to act on this collected data once per
poll and modify the coalescing parameters per ring.

Signed-off-by: Andy Gospodarek <gospo@broadcom.com>
Acked-by: Tal Gilboa <talgi@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 377 insertions, 0 deletions

diff --git a/include/linux/net_dim.h b/include/linux/net_dim.h
new file mode 100644
index 000000000000..741510fb74cb
--- /dev/null
+++ b/include/linux/net_dim.h
@@ -0,0 +1,377 @@
+/*
+ * 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_DEF_PROFILE_CQE 1
+#define NET_DIM_DEF_PROFILE_EQE 1
+
+/* All profiles sizes must be NET_PARAMS_DIM_NUM_PROFILES */
+#define NET_DIM_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_CQE_PROFILES { \
+	{2,  256},             \
+	{8,  128},             \
+	{16, 64},              \
+	{32, 64},              \
+	{64, 64}               \
+}
+
+static const struct net_dim_cq_moder
+profile[NET_DIM_CQ_PERIOD_NUM_MODES][NET_DIM_PARAMS_NUM_PROFILES] = {
+	NET_DIM_EQE_PROFILES,
+	NET_DIM_CQE_PROFILES,
+};
+
+static inline struct net_dim_cq_moder net_dim_get_profile(u8 cq_period_mode,
+							  int ix)
+{
+	struct net_dim_cq_moder cq_moder;
+
+	cq_moder = 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_profile(u8 rx_cq_period_mode)
+{
+	int default_profile_ix;
+
+	if (rx_cq_period_mode == NET_DIM_CQ_PERIOD_MODE_START_FROM_CQE)
+		default_profile_ix = NET_DIM_DEF_PROFILE_CQE;
+	else /* NET_DIM_CQ_PERIOD_MODE_START_FROM_EQE */
+		default_profile_ix = NET_DIM_DEF_PROFILE_EQE;
+
+	return net_dim_get_profile(rx_cq_period_mode, default_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) \
+	(((100 * 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 (IS_SIGNIFICANT_DIFF(curr->ppms, prev->ppms))
+		return (curr->ppms > prev->ppms) ? NET_DIM_STATS_BETTER :
+						   NET_DIM_STATS_WORSE;
+
+	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 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 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,
+			   u16 event_ctr,
+			   u64 packets,
+			   u64 bytes)
+{
+	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), event_ctr,
+				  dim->start_sample.event_ctr);
+		if (nevents < NET_DIM_NEVENTS)
+			break;
+		net_dim_sample(event_ctr, packets, bytes, &end_sample);
+		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(event_ctr, packets, bytes, &dim->start_sample);
+		dim->state = NET_DIM_MEASURE_IN_PROGRESS;
+		break;
+	case NET_DIM_APPLY_NEW_PROFILE:
+		break;
+	}
+}
+
+#endif /* NET_DIM_H */