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12446c67 MN |
1 | /* |
2 | * Copyright 2007, Mattias Nissler <mattias.nissler@gmx.de> | |
ca5fbca9 | 3 | * Copyright 2007, Stefano Brivio <stefano.brivio@polimi.it> |
12446c67 MN |
4 | * |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License version 2 as | |
7 | * published by the Free Software Foundation. | |
8 | */ | |
9 | ||
10 | #ifndef RC80211_PID_H | |
11 | #define RC80211_PID_H | |
12 | ||
1b507e7e SB |
13 | /* Sampling period for measuring percentage of failed frames in ms. */ |
14 | #define RC_PID_INTERVAL 125 | |
12446c67 MN |
15 | |
16 | /* Exponential averaging smoothness (used for I part of PID controller) */ | |
d439810b SB |
17 | #define RC_PID_SMOOTHING_SHIFT 3 |
18 | #define RC_PID_SMOOTHING (1 << RC_PID_SMOOTHING_SHIFT) | |
12446c67 MN |
19 | |
20 | /* Sharpening factor (used for D part of PID controller) */ | |
d439810b SB |
21 | #define RC_PID_SHARPENING_FACTOR 0 |
22 | #define RC_PID_SHARPENING_DURATION 0 | |
12446c67 MN |
23 | |
24 | /* Fixed point arithmetic shifting amount. */ | |
d439810b | 25 | #define RC_PID_ARITH_SHIFT 8 |
12446c67 MN |
26 | |
27 | /* Fixed point arithmetic factor. */ | |
d439810b | 28 | #define RC_PID_ARITH_FACTOR (1 << RC_PID_ARITH_SHIFT) |
12446c67 MN |
29 | |
30 | /* Proportional PID component coefficient. */ | |
d439810b | 31 | #define RC_PID_COEFF_P 15 |
12446c67 | 32 | /* Integral PID component coefficient. */ |
d439810b | 33 | #define RC_PID_COEFF_I 9 |
12446c67 | 34 | /* Derivative PID component coefficient. */ |
d439810b | 35 | #define RC_PID_COEFF_D 15 |
12446c67 MN |
36 | |
37 | /* Target failed frames rate for the PID controller. NB: This effectively gives | |
38 | * maximum failed frames percentage we're willing to accept. If the wireless | |
39 | * link quality is good, the controller will fail to adjust failed frames | |
40 | * percentage to the target. This is intentional. | |
41 | */ | |
d439810b | 42 | #define RC_PID_TARGET_PF 14 |
12446c67 MN |
43 | |
44 | /* Rate behaviour normalization quantity over time. */ | |
d439810b | 45 | #define RC_PID_NORM_OFFSET 3 |
12446c67 MN |
46 | |
47 | /* Push high rates right after loading. */ | |
d439810b | 48 | #define RC_PID_FAST_START 0 |
12446c67 MN |
49 | |
50 | /* Arithmetic right shift for positive and negative values for ISO C. */ | |
51 | #define RC_PID_DO_ARITH_RIGHT_SHIFT(x, y) \ | |
c6a1fa12 | 52 | ((x) < 0 ? -((-(x)) >> (y)) : (x) >> (y)) |
12446c67 MN |
53 | |
54 | enum rc_pid_event_type { | |
55 | RC_PID_EVENT_TYPE_TX_STATUS, | |
56 | RC_PID_EVENT_TYPE_RATE_CHANGE, | |
57 | RC_PID_EVENT_TYPE_TX_RATE, | |
58 | RC_PID_EVENT_TYPE_PF_SAMPLE, | |
59 | }; | |
60 | ||
61 | union rc_pid_event_data { | |
62 | /* RC_PID_EVENT_TX_STATUS */ | |
63 | struct { | |
e6a9854b | 64 | u32 flags; |
e039fa4a | 65 | struct ieee80211_tx_info tx_status; |
12446c67 MN |
66 | }; |
67 | /* RC_PID_EVENT_TYPE_RATE_CHANGE */ | |
68 | /* RC_PID_EVENT_TYPE_TX_RATE */ | |
69 | struct { | |
70 | int index; | |
71 | int rate; | |
72 | }; | |
73 | /* RC_PID_EVENT_TYPE_PF_SAMPLE */ | |
74 | struct { | |
75 | s32 pf_sample; | |
76 | s32 prop_err; | |
77 | s32 int_err; | |
78 | s32 der_err; | |
79 | }; | |
80 | }; | |
81 | ||
82 | struct rc_pid_event { | |
83 | /* The time when the event occured */ | |
84 | unsigned long timestamp; | |
85 | ||
86 | /* Event ID number */ | |
87 | unsigned int id; | |
88 | ||
89 | /* Type of event */ | |
90 | enum rc_pid_event_type type; | |
91 | ||
92 | /* type specific data */ | |
93 | union rc_pid_event_data data; | |
94 | }; | |
95 | ||
96 | /* Size of the event ring buffer. */ | |
97 | #define RC_PID_EVENT_RING_SIZE 32 | |
98 | ||
99 | struct rc_pid_event_buffer { | |
100 | /* Counter that generates event IDs */ | |
101 | unsigned int ev_count; | |
102 | ||
103 | /* Ring buffer of events */ | |
104 | struct rc_pid_event ring[RC_PID_EVENT_RING_SIZE]; | |
105 | ||
106 | /* Index to the entry in events_buf to be reused */ | |
107 | unsigned int next_entry; | |
108 | ||
109 | /* Lock that guards against concurrent access to this buffer struct */ | |
110 | spinlock_t lock; | |
111 | ||
112 | /* Wait queue for poll/select and blocking I/O */ | |
113 | wait_queue_head_t waitqueue; | |
114 | }; | |
115 | ||
116 | struct rc_pid_events_file_info { | |
117 | /* The event buffer we read */ | |
118 | struct rc_pid_event_buffer *events; | |
119 | ||
120 | /* The entry we have should read next */ | |
121 | unsigned int next_entry; | |
122 | }; | |
123 | ||
ca5fbca9 SB |
124 | /** |
125 | * struct rc_pid_debugfs_entries - tunable parameters | |
126 | * | |
127 | * Algorithm parameters, tunable via debugfs. | |
ca5fbca9 SB |
128 | * @target: target percentage for failed frames |
129 | * @sampling_period: error sampling interval in milliseconds | |
130 | * @coeff_p: absolute value of the proportional coefficient | |
131 | * @coeff_i: absolute value of the integral coefficient | |
132 | * @coeff_d: absolute value of the derivative coefficient | |
133 | * @smoothing_shift: absolute value of the integral smoothing factor (i.e. | |
134 | * amount of smoothing introduced by the exponential moving average) | |
135 | * @sharpen_factor: absolute value of the derivative sharpening factor (i.e. | |
136 | * amount of emphasis given to the derivative term after low activity | |
137 | * events) | |
138 | * @sharpen_duration: duration of the sharpening effect after the detected low | |
139 | * activity event, relative to sampling_period | |
140 | * @norm_offset: amount of normalization periodically performed on the learnt | |
141 | * rate behaviour values (lower means we should trust more what we learnt | |
142 | * about behaviour of rates, higher means we should trust more the natural | |
143 | * ordering of rates) | |
ca5fbca9 | 144 | */ |
1946b74c | 145 | struct rc_pid_debugfs_entries { |
1946b74c MN |
146 | struct dentry *target; |
147 | struct dentry *sampling_period; | |
148 | struct dentry *coeff_p; | |
149 | struct dentry *coeff_i; | |
150 | struct dentry *coeff_d; | |
151 | struct dentry *smoothing_shift; | |
152 | struct dentry *sharpen_factor; | |
153 | struct dentry *sharpen_duration; | |
154 | struct dentry *norm_offset; | |
1946b74c MN |
155 | }; |
156 | ||
12446c67 | 157 | void rate_control_pid_event_tx_status(struct rc_pid_event_buffer *buf, |
e039fa4a | 158 | struct ieee80211_tx_info *stat); |
12446c67 MN |
159 | |
160 | void rate_control_pid_event_rate_change(struct rc_pid_event_buffer *buf, | |
161 | int index, int rate); | |
162 | ||
163 | void rate_control_pid_event_tx_rate(struct rc_pid_event_buffer *buf, | |
164 | int index, int rate); | |
165 | ||
166 | void rate_control_pid_event_pf_sample(struct rc_pid_event_buffer *buf, | |
167 | s32 pf_sample, s32 prop_err, | |
168 | s32 int_err, s32 der_err); | |
169 | ||
170 | void rate_control_pid_add_sta_debugfs(void *priv, void *priv_sta, | |
171 | struct dentry *dir); | |
172 | ||
173 | void rate_control_pid_remove_sta_debugfs(void *priv, void *priv_sta); | |
174 | ||
175 | struct rc_pid_sta_info { | |
176 | unsigned long last_change; | |
177 | unsigned long last_sample; | |
178 | ||
179 | u32 tx_num_failed; | |
180 | u32 tx_num_xmit; | |
181 | ||
ae17e986 JB |
182 | int txrate_idx; |
183 | ||
12446c67 MN |
184 | /* Average failed frames percentage error (i.e. actual vs. target |
185 | * percentage), scaled by RC_PID_SMOOTHING. This value is computed | |
186 | * using using an exponential weighted average technique: | |
187 | * | |
188 | * (RC_PID_SMOOTHING - 1) * err_avg_old + err | |
189 | * err_avg = ------------------------------------------ | |
190 | * RC_PID_SMOOTHING | |
191 | * | |
192 | * where err_avg is the new approximation, err_avg_old the previous one | |
193 | * and err is the error w.r.t. to the current failed frames percentage | |
194 | * sample. Note that the bigger RC_PID_SMOOTHING the more weight is | |
195 | * given to the previous estimate, resulting in smoother behavior (i.e. | |
196 | * corresponding to a longer integration window). | |
197 | * | |
198 | * For computation, we actually don't use the above formula, but this | |
199 | * one: | |
200 | * | |
201 | * err_avg_scaled = err_avg_old_scaled - err_avg_old + err | |
202 | * | |
203 | * where: | |
204 | * err_avg_scaled = err * RC_PID_SMOOTHING | |
205 | * err_avg_old_scaled = err_avg_old * RC_PID_SMOOTHING | |
206 | * | |
207 | * This avoids floating point numbers and the per_failed_old value can | |
208 | * easily be obtained by shifting per_failed_old_scaled right by | |
209 | * RC_PID_SMOOTHING_SHIFT. | |
210 | */ | |
211 | s32 err_avg_sc; | |
212 | ||
213 | /* Last framed failes percentage sample. */ | |
214 | u32 last_pf; | |
215 | ||
216 | /* Sharpening needed. */ | |
217 | u8 sharp_cnt; | |
218 | ||
219 | #ifdef CONFIG_MAC80211_DEBUGFS | |
220 | /* Event buffer */ | |
221 | struct rc_pid_event_buffer events; | |
222 | ||
223 | /* Events debugfs file entry */ | |
224 | struct dentry *events_entry; | |
225 | #endif | |
226 | }; | |
227 | ||
228 | /* Algorithm parameters. We keep them on a per-algorithm approach, so they can | |
229 | * be tuned individually for each interface. | |
230 | */ | |
231 | struct rc_pid_rateinfo { | |
232 | ||
233 | /* Map sorted rates to rates in ieee80211_hw_mode. */ | |
234 | int index; | |
235 | ||
236 | /* Map rates in ieee80211_hw_mode to sorted rates. */ | |
237 | int rev_index; | |
238 | ||
239 | /* Did we do any measurement on this rate? */ | |
240 | bool valid; | |
241 | ||
242 | /* Comparison with the lowest rate. */ | |
243 | int diff; | |
244 | }; | |
245 | ||
246 | struct rc_pid_info { | |
247 | ||
248 | /* The failed frames percentage target. */ | |
249 | unsigned int target; | |
250 | ||
251 | /* Rate at which failed frames percentage is sampled in 0.001s. */ | |
252 | unsigned int sampling_period; | |
253 | ||
254 | /* P, I and D coefficients. */ | |
255 | int coeff_p; | |
256 | int coeff_i; | |
257 | int coeff_d; | |
258 | ||
259 | /* Exponential averaging shift. */ | |
260 | unsigned int smoothing_shift; | |
261 | ||
1946b74c MN |
262 | /* Sharpening factor and duration. */ |
263 | unsigned int sharpen_factor; | |
12446c67 MN |
264 | unsigned int sharpen_duration; |
265 | ||
266 | /* Normalization offset. */ | |
267 | unsigned int norm_offset; | |
268 | ||
12446c67 MN |
269 | /* Rates information. */ |
270 | struct rc_pid_rateinfo *rinfo; | |
271 | ||
272 | /* Index of the last used rate. */ | |
273 | int oldrate; | |
1946b74c MN |
274 | |
275 | #ifdef CONFIG_MAC80211_DEBUGFS | |
276 | /* Debugfs entries created for the parameters above. */ | |
277 | struct rc_pid_debugfs_entries dentries; | |
278 | #endif | |
12446c67 MN |
279 | }; |
280 | ||
281 | #endif /* RC80211_PID_H */ |