summaryrefslogtreecommitdiff
path: root/include/linux/dim.h
blob: aa9bdd47a648590293fffee5e43371764ee2bc0b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
/* Copyright (c) 2019 Mellanox Technologies. */

#ifndef DIM_H
#define DIM_H

#include <linux/module.h>

/**
 * Number of events between DIM iterations.
 * Causes a moderation of the algorithm run.
 */
#define DIM_NEVENTS 64

/**
 * Is a difference between values justifies taking an action.
 * We consider 10% difference as significant.
 */
#define IS_SIGNIFICANT_DIFF(val, ref) \
	(((100UL * abs((val) - (ref))) / (ref)) > 10)

/**
 * Calculate the gap between two values.
 * Take wrap-around and variable size into consideration.
 */
#define BIT_GAP(bits, end, start) ((((end) - (start)) + BIT_ULL(bits)) \
		& (BIT_ULL(bits) - 1))

/**
 * Structure for CQ moderation values.
 * Used for communications between DIM and its consumer.
 *
 * @usec: CQ timer suggestion (by DIM)
 * @pkts: CQ packet counter suggestion (by DIM)
 * @cq_period_mode: CQ priod count mode (from CQE/EQE)
 */
struct dim_cq_moder {
	u16 usec;
	u16 pkts;
	u16 comps;
	u8 cq_period_mode;
};

/**
 * Structure for DIM sample data.
 * Used for communications between DIM and its consumer.
 *
 * @time: Sample timestamp
 * @pkt_ctr: Number of packets
 * @byte_ctr: Number of bytes
 * @event_ctr: Number of events
 */
struct dim_sample {
	ktime_t time;
	u32 pkt_ctr;
	u32 byte_ctr;
	u16 event_ctr;
	u32 comp_ctr;
};

/**
 * Structure for DIM stats.
 * Used for holding current measured rates.
 *
 * @ppms: Packets per msec
 * @bpms: Bytes per msec
 * @epms: Events per msec
 */
struct dim_stats {
	int ppms; /* packets per msec */
	int bpms; /* bytes per msec */
	int epms; /* events per msec */
	int cpms; /* completions per msec */
	int cpe_ratio; /* ratio of completions to events */
};

/**
 * Main structure for dynamic interrupt moderation (DIM).
 * Used for holding all information about a specific DIM instance.
 *
 * @state: Algorithm state (see below)
 * @prev_stats: Measured rates from previous iteration (for comparison)
 * @start_sample: Sampled data at start of current iteration
 * @work: Work to perform on action required
 * @profile_ix: Current moderation profile
 * @mode: CQ period count mode
 * @tune_state: Algorithm tuning state (see below)
 * @steps_right: Number of steps taken towards higher moderation
 * @steps_left: Number of steps taken towards lower moderation
 * @tired: Parking depth counter
 */
struct dim {
	u8 state;
	struct dim_stats prev_stats;
	struct dim_sample start_sample;
	struct dim_sample measuring_sample;
	struct work_struct work;
	u8 profile_ix;
	u8 mode;
	u8 tune_state;
	u8 steps_right;
	u8 steps_left;
	u8 tired;
};

/**
 * enum dim_cq_period_mode
 *
 * These are the modes for CQ period count.
 *
 * @DIM_CQ_PERIOD_MODE_START_FROM_EQE: Start counting from EQE
 * @DIM_CQ_PERIOD_MODE_START_FROM_CQE: Start counting from CQE (implies timer reset)
 * @DIM_CQ_PERIOD_NUM_MODES: Number of modes
 */
enum {
	DIM_CQ_PERIOD_MODE_START_FROM_EQE = 0x0,
	DIM_CQ_PERIOD_MODE_START_FROM_CQE = 0x1,
	DIM_CQ_PERIOD_NUM_MODES
};

/**
 * enum dim_state
 *
 * These are the DIM algorithm states.
 * These will determine if the algorithm is in a valid state to start an iteration.
 *
 * @DIM_START_MEASURE: This is the first iteration (also after applying a new profile)
 * @DIM_MEASURE_IN_PROGRESS: Algorithm is already in progress - check if
 * need to perform an action
 * @DIM_APPLY_NEW_PROFILE: DIM consumer is currently applying a profile - no need to measure
 */
enum {
	DIM_START_MEASURE,
	DIM_MEASURE_IN_PROGRESS,
	DIM_APPLY_NEW_PROFILE,
};

/**
 * enum dim_tune_state
 *
 * These are the DIM algorithm tune states.
 * These will determine which action the algorithm should perform.
 *
 * @DIM_PARKING_ON_TOP: Algorithm found a local top point - exit on significant difference
 * @DIM_PARKING_TIRED: Algorithm found a deep top point - don't exit if tired > 0
 * @DIM_GOING_RIGHT: Algorithm is currently trying higher moderation levels
 * @DIM_GOING_LEFT: Algorithm is currently trying lower moderation levels
 */
enum {
	DIM_PARKING_ON_TOP,
	DIM_PARKING_TIRED,
	DIM_GOING_RIGHT,
	DIM_GOING_LEFT,
};

/**
 * enum dim_stats_state
 *
 * These are the DIM algorithm statistics states.
 * These will determine the verdict of current iteration.
 *
 * @DIM_STATS_WORSE: Current iteration shows worse performance than before
 * @DIM_STATS_WORSE: Current iteration shows same performance than before
 * @DIM_STATS_WORSE: Current iteration shows better performance than before
 */
enum {
	DIM_STATS_WORSE,
	DIM_STATS_SAME,
	DIM_STATS_BETTER,
};

/**
 * enum dim_step_result
 *
 * These are the DIM algorithm step results.
 * These describe the result of a step.
 *
 * @DIM_STEPPED: Performed a regular step
 * @DIM_TOO_TIRED: Same kind of step was done multiple times - should go to
 * tired parking
 * @DIM_ON_EDGE: Stepped to the most left/right profile
 */
enum {
	DIM_STEPPED,
	DIM_TOO_TIRED,
	DIM_ON_EDGE,
};

/**
 *	dim_on_top - check if current state is a good place to stop (top location)
 *	@dim: DIM context
 *
 * Check if current profile is a good place to park at.
 * This will result in reducing the DIM checks frequency as we assume we
 * shouldn't probably change profiles, unless traffic pattern wasn't changed.
 */
bool dim_on_top(struct dim *dim);

/**
 *	dim_turn - change profile alterning direction
 *	@dim: DIM context
 *
 * Go left if we were going right and vice-versa.
 * Do nothing if currently parking.
 */
void dim_turn(struct dim *dim);

/**
 *	dim_park_on_top - enter a parking state on a top location
 *	@dim: DIM context
 *
 * Enter parking state.
 * Clear all movement history.
 */
void dim_park_on_top(struct dim *dim);

/**
 *	dim_park_tired - enter a tired parking state
 *	@dim: DIM context
 *
 * Enter parking state.
 * Clear all movement history and cause DIM checks frequency to reduce.
 */
void dim_park_tired(struct dim *dim);

/**
 *	dim_calc_stats - calculate the difference between two samples
 *	@start: start sample
 *	@end: end sample
 *	@curr_stats: delta between samples
 *
 * Calculate the delta between two samples (in data rates).
 * Takes into consideration counter wrap-around.
 */
void dim_calc_stats(struct dim_sample *start, struct dim_sample *end,
		    struct dim_stats *curr_stats);

/**
 *	dim_update_sample - set a sample's fields with give values
 *	@event_ctr: number of events to set
 *	@packets: number of packets to set
 *	@bytes: number of bytes to set
 *	@s: DIM sample
 */
static inline void
dim_update_sample(u16 event_ctr, u64 packets, u64 bytes, struct dim_sample *s)
{
	s->time	     = ktime_get();
	s->pkt_ctr   = packets;
	s->byte_ctr  = bytes;
	s->event_ctr = event_ctr;
}

/**
 *	dim_update_sample_with_comps - set a sample's fields with given
 *	values including the completion parameter
 *	@event_ctr: number of events to set
 *	@packets: number of packets to set
 *	@bytes: number of bytes to set
 *	@comps: number of completions to set
 *	@s: DIM sample
 */
static inline void
dim_update_sample_with_comps(u16 event_ctr, u64 packets, u64 bytes, u64 comps,
			     struct dim_sample *s)
{
	dim_update_sample(event_ctr, packets, bytes, s);
	s->comp_ctr = comps;
}

/* Net DIM */

/*
 * Net DIM profiles:
 *        There are different set of profiles for each CQ period mode.
 *        There are different set of profiles for RX/TX CQs.
 *        Each profile size must be of NET_DIM_PARAMS_NUM_PROFILES
 */
#define NET_DIM_PARAMS_NUM_PROFILES 5
#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

#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 dim_cq_moder
rx_profile[DIM_CQ_PERIOD_NUM_MODES][NET_DIM_PARAMS_NUM_PROFILES] = {
	NET_DIM_RX_EQE_PROFILES,
	NET_DIM_RX_CQE_PROFILES,
};

static const struct dim_cq_moder
tx_profile[DIM_CQ_PERIOD_NUM_MODES][NET_DIM_PARAMS_NUM_PROFILES] = {
	NET_DIM_TX_EQE_PROFILES,
	NET_DIM_TX_CQE_PROFILES,
};

/**
 *	net_dim_get_rx_moderation - provide a CQ moderation object for the given RX profile
 *	@cq_period_mode: CQ period mode
 *	@ix: Profile index
 */
struct dim_cq_moder net_dim_get_rx_moderation(u8 cq_period_mode, int ix);

/**
 *	net_dim_get_def_rx_moderation - provide the default RX moderation
 *	@cq_period_mode: CQ period mode
 */
struct dim_cq_moder net_dim_get_def_rx_moderation(u8 cq_period_mode);

/**
 *	net_dim_get_tx_moderation - provide a CQ moderation object for the given TX profile
 *	@cq_period_mode: CQ period mode
 *	@ix: Profile index
 */
struct dim_cq_moder net_dim_get_tx_moderation(u8 cq_period_mode, int ix);

/**
 *	net_dim_get_def_tx_moderation - provide the default TX moderation
 *	@cq_period_mode: CQ period mode
 */
struct dim_cq_moder net_dim_get_def_tx_moderation(u8 cq_period_mode);

/**
 *	net_dim - main DIM algorithm entry point
 *	@dim: DIM instance information
 *	@end_sample: Current data measurement
 *
 * Called by the consumer.
 * This is the main logic of the algorithm, where data is processed in order to decide on next
 * required action.
 */
void net_dim(struct dim *dim, struct dim_sample end_sample);

#endif /* DIM_H */