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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 | ||
13 | /* Sampling period for measuring percentage of failed frames. */ | |
d439810b | 14 | #define RC_PID_INTERVAL (HZ / 8) |
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 |
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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 |
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49 | |
50 | /* Arithmetic right shift for positive and negative values for ISO C. */ | |
51 | #define RC_PID_DO_ARITH_RIGHT_SHIFT(x, y) \ | |
52 | (x) < 0 ? -((-(x)) >> (y)) : (x) >> (y) | |
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 { | |
64 | struct ieee80211_tx_status tx_status; | |
65 | }; | |
66 | /* RC_PID_EVENT_TYPE_RATE_CHANGE */ | |
67 | /* RC_PID_EVENT_TYPE_TX_RATE */ | |
68 | struct { | |
69 | int index; | |
70 | int rate; | |
71 | }; | |
72 | /* RC_PID_EVENT_TYPE_PF_SAMPLE */ | |
73 | struct { | |
74 | s32 pf_sample; | |
75 | s32 prop_err; | |
76 | s32 int_err; | |
77 | s32 der_err; | |
78 | }; | |
79 | }; | |
80 | ||
81 | struct rc_pid_event { | |
82 | /* The time when the event occured */ | |
83 | unsigned long timestamp; | |
84 | ||
85 | /* Event ID number */ | |
86 | unsigned int id; | |
87 | ||
88 | /* Type of event */ | |
89 | enum rc_pid_event_type type; | |
90 | ||
91 | /* type specific data */ | |
92 | union rc_pid_event_data data; | |
93 | }; | |
94 | ||
95 | /* Size of the event ring buffer. */ | |
96 | #define RC_PID_EVENT_RING_SIZE 32 | |
97 | ||
98 | struct rc_pid_event_buffer { | |
99 | /* Counter that generates event IDs */ | |
100 | unsigned int ev_count; | |
101 | ||
102 | /* Ring buffer of events */ | |
103 | struct rc_pid_event ring[RC_PID_EVENT_RING_SIZE]; | |
104 | ||
105 | /* Index to the entry in events_buf to be reused */ | |
106 | unsigned int next_entry; | |
107 | ||
108 | /* Lock that guards against concurrent access to this buffer struct */ | |
109 | spinlock_t lock; | |
110 | ||
111 | /* Wait queue for poll/select and blocking I/O */ | |
112 | wait_queue_head_t waitqueue; | |
113 | }; | |
114 | ||
115 | struct rc_pid_events_file_info { | |
116 | /* The event buffer we read */ | |
117 | struct rc_pid_event_buffer *events; | |
118 | ||
119 | /* The entry we have should read next */ | |
120 | unsigned int next_entry; | |
121 | }; | |
122 | ||
ca5fbca9 SB |
123 | /** |
124 | * struct rc_pid_debugfs_entries - tunable parameters | |
125 | * | |
126 | * Algorithm parameters, tunable via debugfs. | |
127 | * @dir: the debugfs directory for a specific phy | |
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) | |
144 | * @fast_start: if Y, push high rates right after initialization | |
145 | */ | |
1946b74c MN |
146 | struct rc_pid_debugfs_entries { |
147 | struct dentry *dir; | |
148 | struct dentry *target; | |
149 | struct dentry *sampling_period; | |
150 | struct dentry *coeff_p; | |
151 | struct dentry *coeff_i; | |
152 | struct dentry *coeff_d; | |
153 | struct dentry *smoothing_shift; | |
154 | struct dentry *sharpen_factor; | |
155 | struct dentry *sharpen_duration; | |
156 | struct dentry *norm_offset; | |
157 | struct dentry *fast_start; | |
158 | }; | |
159 | ||
12446c67 MN |
160 | void rate_control_pid_event_tx_status(struct rc_pid_event_buffer *buf, |
161 | struct ieee80211_tx_status *stat); | |
162 | ||
163 | void rate_control_pid_event_rate_change(struct rc_pid_event_buffer *buf, | |
164 | int index, int rate); | |
165 | ||
166 | void rate_control_pid_event_tx_rate(struct rc_pid_event_buffer *buf, | |
167 | int index, int rate); | |
168 | ||
169 | void rate_control_pid_event_pf_sample(struct rc_pid_event_buffer *buf, | |
170 | s32 pf_sample, s32 prop_err, | |
171 | s32 int_err, s32 der_err); | |
172 | ||
173 | void rate_control_pid_add_sta_debugfs(void *priv, void *priv_sta, | |
174 | struct dentry *dir); | |
175 | ||
176 | void rate_control_pid_remove_sta_debugfs(void *priv, void *priv_sta); | |
177 | ||
178 | struct rc_pid_sta_info { | |
179 | unsigned long last_change; | |
180 | unsigned long last_sample; | |
181 | ||
182 | u32 tx_num_failed; | |
183 | u32 tx_num_xmit; | |
184 | ||
185 | /* Average failed frames percentage error (i.e. actual vs. target | |
186 | * percentage), scaled by RC_PID_SMOOTHING. This value is computed | |
187 | * using using an exponential weighted average technique: | |
188 | * | |
189 | * (RC_PID_SMOOTHING - 1) * err_avg_old + err | |
190 | * err_avg = ------------------------------------------ | |
191 | * RC_PID_SMOOTHING | |
192 | * | |
193 | * where err_avg is the new approximation, err_avg_old the previous one | |
194 | * and err is the error w.r.t. to the current failed frames percentage | |
195 | * sample. Note that the bigger RC_PID_SMOOTHING the more weight is | |
196 | * given to the previous estimate, resulting in smoother behavior (i.e. | |
197 | * corresponding to a longer integration window). | |
198 | * | |
199 | * For computation, we actually don't use the above formula, but this | |
200 | * one: | |
201 | * | |
202 | * err_avg_scaled = err_avg_old_scaled - err_avg_old + err | |
203 | * | |
204 | * where: | |
205 | * err_avg_scaled = err * RC_PID_SMOOTHING | |
206 | * err_avg_old_scaled = err_avg_old * RC_PID_SMOOTHING | |
207 | * | |
208 | * This avoids floating point numbers and the per_failed_old value can | |
209 | * easily be obtained by shifting per_failed_old_scaled right by | |
210 | * RC_PID_SMOOTHING_SHIFT. | |
211 | */ | |
212 | s32 err_avg_sc; | |
213 | ||
214 | /* Last framed failes percentage sample. */ | |
215 | u32 last_pf; | |
216 | ||
217 | /* Sharpening needed. */ | |
218 | u8 sharp_cnt; | |
219 | ||
220 | #ifdef CONFIG_MAC80211_DEBUGFS | |
221 | /* Event buffer */ | |
222 | struct rc_pid_event_buffer events; | |
223 | ||
224 | /* Events debugfs file entry */ | |
225 | struct dentry *events_entry; | |
226 | #endif | |
227 | }; | |
228 | ||
229 | /* Algorithm parameters. We keep them on a per-algorithm approach, so they can | |
230 | * be tuned individually for each interface. | |
231 | */ | |
232 | struct rc_pid_rateinfo { | |
233 | ||
234 | /* Map sorted rates to rates in ieee80211_hw_mode. */ | |
235 | int index; | |
236 | ||
237 | /* Map rates in ieee80211_hw_mode to sorted rates. */ | |
238 | int rev_index; | |
239 | ||
240 | /* Did we do any measurement on this rate? */ | |
241 | bool valid; | |
242 | ||
243 | /* Comparison with the lowest rate. */ | |
244 | int diff; | |
245 | }; | |
246 | ||
247 | struct rc_pid_info { | |
248 | ||
249 | /* The failed frames percentage target. */ | |
250 | unsigned int target; | |
251 | ||
252 | /* Rate at which failed frames percentage is sampled in 0.001s. */ | |
253 | unsigned int sampling_period; | |
254 | ||
255 | /* P, I and D coefficients. */ | |
256 | int coeff_p; | |
257 | int coeff_i; | |
258 | int coeff_d; | |
259 | ||
260 | /* Exponential averaging shift. */ | |
261 | unsigned int smoothing_shift; | |
262 | ||
1946b74c MN |
263 | /* Sharpening factor and duration. */ |
264 | unsigned int sharpen_factor; | |
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265 | unsigned int sharpen_duration; |
266 | ||
267 | /* Normalization offset. */ | |
268 | unsigned int norm_offset; | |
269 | ||
270 | /* Fast starst parameter. */ | |
271 | unsigned int fast_start; | |
272 | ||
273 | /* Rates information. */ | |
274 | struct rc_pid_rateinfo *rinfo; | |
275 | ||
276 | /* Index of the last used rate. */ | |
277 | int oldrate; | |
1946b74c MN |
278 | |
279 | #ifdef CONFIG_MAC80211_DEBUGFS | |
280 | /* Debugfs entries created for the parameters above. */ | |
281 | struct rc_pid_debugfs_entries dentries; | |
282 | #endif | |
12446c67 MN |
283 | }; |
284 | ||
285 | #endif /* RC80211_PID_H */ |