Mattias Nissler | 12446c6 | 2007-12-19 01:27:18 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2007, Mattias Nissler <mattias.nissler@gmx.de> |
Stefano Brivio | ca5fbca | 2007-12-23 04:40:32 +0100 | [diff] [blame] | 3 | * Copyright 2007, Stefano Brivio <stefano.brivio@polimi.it> |
Mattias Nissler | 12446c6 | 2007-12-19 01:27:18 +0100 | [diff] [blame] | 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 | |
Stefano Brivio | 1b507e7 | 2007-12-23 17:49:00 +0100 | [diff] [blame] | 13 | /* Sampling period for measuring percentage of failed frames in ms. */ |
| 14 | #define RC_PID_INTERVAL 125 |
Mattias Nissler | 12446c6 | 2007-12-19 01:27:18 +0100 | [diff] [blame] | 15 | |
| 16 | /* Exponential averaging smoothness (used for I part of PID controller) */ |
Stefano Brivio | d439810 | 2007-12-23 04:44:56 +0100 | [diff] [blame] | 17 | #define RC_PID_SMOOTHING_SHIFT 3 |
| 18 | #define RC_PID_SMOOTHING (1 << RC_PID_SMOOTHING_SHIFT) |
Mattias Nissler | 12446c6 | 2007-12-19 01:27:18 +0100 | [diff] [blame] | 19 | |
| 20 | /* Sharpening factor (used for D part of PID controller) */ |
Stefano Brivio | d439810 | 2007-12-23 04:44:56 +0100 | [diff] [blame] | 21 | #define RC_PID_SHARPENING_FACTOR 0 |
| 22 | #define RC_PID_SHARPENING_DURATION 0 |
Mattias Nissler | 12446c6 | 2007-12-19 01:27:18 +0100 | [diff] [blame] | 23 | |
| 24 | /* Fixed point arithmetic shifting amount. */ |
Stefano Brivio | d439810 | 2007-12-23 04:44:56 +0100 | [diff] [blame] | 25 | #define RC_PID_ARITH_SHIFT 8 |
Mattias Nissler | 12446c6 | 2007-12-19 01:27:18 +0100 | [diff] [blame] | 26 | |
| 27 | /* Fixed point arithmetic factor. */ |
Stefano Brivio | d439810 | 2007-12-23 04:44:56 +0100 | [diff] [blame] | 28 | #define RC_PID_ARITH_FACTOR (1 << RC_PID_ARITH_SHIFT) |
Mattias Nissler | 12446c6 | 2007-12-19 01:27:18 +0100 | [diff] [blame] | 29 | |
| 30 | /* Proportional PID component coefficient. */ |
Stefano Brivio | d439810 | 2007-12-23 04:44:56 +0100 | [diff] [blame] | 31 | #define RC_PID_COEFF_P 15 |
Mattias Nissler | 12446c6 | 2007-12-19 01:27:18 +0100 | [diff] [blame] | 32 | /* Integral PID component coefficient. */ |
Stefano Brivio | d439810 | 2007-12-23 04:44:56 +0100 | [diff] [blame] | 33 | #define RC_PID_COEFF_I 9 |
Mattias Nissler | 12446c6 | 2007-12-19 01:27:18 +0100 | [diff] [blame] | 34 | /* Derivative PID component coefficient. */ |
Stefano Brivio | d439810 | 2007-12-23 04:44:56 +0100 | [diff] [blame] | 35 | #define RC_PID_COEFF_D 15 |
Mattias Nissler | 12446c6 | 2007-12-19 01:27:18 +0100 | [diff] [blame] | 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 | */ |
Stefano Brivio | d439810 | 2007-12-23 04:44:56 +0100 | [diff] [blame] | 42 | #define RC_PID_TARGET_PF 14 |
Mattias Nissler | 12446c6 | 2007-12-19 01:27:18 +0100 | [diff] [blame] | 43 | |
| 44 | /* Rate behaviour normalization quantity over time. */ |
Stefano Brivio | d439810 | 2007-12-23 04:44:56 +0100 | [diff] [blame] | 45 | #define RC_PID_NORM_OFFSET 3 |
Mattias Nissler | 12446c6 | 2007-12-19 01:27:18 +0100 | [diff] [blame] | 46 | |
| 47 | /* Push high rates right after loading. */ |
Stefano Brivio | d439810 | 2007-12-23 04:44:56 +0100 | [diff] [blame] | 48 | #define RC_PID_FAST_START 0 |
Mattias Nissler | 12446c6 | 2007-12-19 01:27:18 +0100 | [diff] [blame] | 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 | |
Stefano Brivio | ca5fbca | 2007-12-23 04:40:32 +0100 | [diff] [blame] | 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) |
Stefano Brivio | ca5fbca | 2007-12-23 04:40:32 +0100 | [diff] [blame] | 144 | */ |
Mattias Nissler | 1946b74 | 2007-12-20 13:27:26 +0100 | [diff] [blame] | 145 | struct rc_pid_debugfs_entries { |
| 146 | struct dentry *dir; |
| 147 | struct dentry *target; |
| 148 | struct dentry *sampling_period; |
| 149 | struct dentry *coeff_p; |
| 150 | struct dentry *coeff_i; |
| 151 | struct dentry *coeff_d; |
| 152 | struct dentry *smoothing_shift; |
| 153 | struct dentry *sharpen_factor; |
| 154 | struct dentry *sharpen_duration; |
| 155 | struct dentry *norm_offset; |
Mattias Nissler | 1946b74 | 2007-12-20 13:27:26 +0100 | [diff] [blame] | 156 | }; |
| 157 | |
Mattias Nissler | 12446c6 | 2007-12-19 01:27:18 +0100 | [diff] [blame] | 158 | void rate_control_pid_event_tx_status(struct rc_pid_event_buffer *buf, |
| 159 | struct ieee80211_tx_status *stat); |
| 160 | |
| 161 | void rate_control_pid_event_rate_change(struct rc_pid_event_buffer *buf, |
| 162 | int index, int rate); |
| 163 | |
| 164 | void rate_control_pid_event_tx_rate(struct rc_pid_event_buffer *buf, |
| 165 | int index, int rate); |
| 166 | |
| 167 | void rate_control_pid_event_pf_sample(struct rc_pid_event_buffer *buf, |
| 168 | s32 pf_sample, s32 prop_err, |
| 169 | s32 int_err, s32 der_err); |
| 170 | |
| 171 | void rate_control_pid_add_sta_debugfs(void *priv, void *priv_sta, |
| 172 | struct dentry *dir); |
| 173 | |
| 174 | void rate_control_pid_remove_sta_debugfs(void *priv, void *priv_sta); |
| 175 | |
| 176 | struct rc_pid_sta_info { |
| 177 | unsigned long last_change; |
| 178 | unsigned long last_sample; |
| 179 | |
| 180 | u32 tx_num_failed; |
| 181 | u32 tx_num_xmit; |
| 182 | |
| 183 | /* Average failed frames percentage error (i.e. actual vs. target |
| 184 | * percentage), scaled by RC_PID_SMOOTHING. This value is computed |
| 185 | * using using an exponential weighted average technique: |
| 186 | * |
| 187 | * (RC_PID_SMOOTHING - 1) * err_avg_old + err |
| 188 | * err_avg = ------------------------------------------ |
| 189 | * RC_PID_SMOOTHING |
| 190 | * |
| 191 | * where err_avg is the new approximation, err_avg_old the previous one |
| 192 | * and err is the error w.r.t. to the current failed frames percentage |
| 193 | * sample. Note that the bigger RC_PID_SMOOTHING the more weight is |
| 194 | * given to the previous estimate, resulting in smoother behavior (i.e. |
| 195 | * corresponding to a longer integration window). |
| 196 | * |
| 197 | * For computation, we actually don't use the above formula, but this |
| 198 | * one: |
| 199 | * |
| 200 | * err_avg_scaled = err_avg_old_scaled - err_avg_old + err |
| 201 | * |
| 202 | * where: |
| 203 | * err_avg_scaled = err * RC_PID_SMOOTHING |
| 204 | * err_avg_old_scaled = err_avg_old * RC_PID_SMOOTHING |
| 205 | * |
| 206 | * This avoids floating point numbers and the per_failed_old value can |
| 207 | * easily be obtained by shifting per_failed_old_scaled right by |
| 208 | * RC_PID_SMOOTHING_SHIFT. |
| 209 | */ |
| 210 | s32 err_avg_sc; |
| 211 | |
| 212 | /* Last framed failes percentage sample. */ |
| 213 | u32 last_pf; |
| 214 | |
| 215 | /* Sharpening needed. */ |
| 216 | u8 sharp_cnt; |
| 217 | |
| 218 | #ifdef CONFIG_MAC80211_DEBUGFS |
| 219 | /* Event buffer */ |
| 220 | struct rc_pid_event_buffer events; |
| 221 | |
| 222 | /* Events debugfs file entry */ |
| 223 | struct dentry *events_entry; |
| 224 | #endif |
| 225 | }; |
| 226 | |
| 227 | /* Algorithm parameters. We keep them on a per-algorithm approach, so they can |
| 228 | * be tuned individually for each interface. |
| 229 | */ |
| 230 | struct rc_pid_rateinfo { |
| 231 | |
| 232 | /* Map sorted rates to rates in ieee80211_hw_mode. */ |
| 233 | int index; |
| 234 | |
| 235 | /* Map rates in ieee80211_hw_mode to sorted rates. */ |
| 236 | int rev_index; |
| 237 | |
| 238 | /* Did we do any measurement on this rate? */ |
| 239 | bool valid; |
| 240 | |
| 241 | /* Comparison with the lowest rate. */ |
| 242 | int diff; |
| 243 | }; |
| 244 | |
| 245 | struct rc_pid_info { |
| 246 | |
| 247 | /* The failed frames percentage target. */ |
| 248 | unsigned int target; |
| 249 | |
| 250 | /* Rate at which failed frames percentage is sampled in 0.001s. */ |
| 251 | unsigned int sampling_period; |
| 252 | |
| 253 | /* P, I and D coefficients. */ |
| 254 | int coeff_p; |
| 255 | int coeff_i; |
| 256 | int coeff_d; |
| 257 | |
| 258 | /* Exponential averaging shift. */ |
| 259 | unsigned int smoothing_shift; |
| 260 | |
Mattias Nissler | 1946b74 | 2007-12-20 13:27:26 +0100 | [diff] [blame] | 261 | /* Sharpening factor and duration. */ |
| 262 | unsigned int sharpen_factor; |
Mattias Nissler | 12446c6 | 2007-12-19 01:27:18 +0100 | [diff] [blame] | 263 | unsigned int sharpen_duration; |
| 264 | |
| 265 | /* Normalization offset. */ |
| 266 | unsigned int norm_offset; |
| 267 | |
Mattias Nissler | 12446c6 | 2007-12-19 01:27:18 +0100 | [diff] [blame] | 268 | /* Rates information. */ |
| 269 | struct rc_pid_rateinfo *rinfo; |
| 270 | |
| 271 | /* Index of the last used rate. */ |
| 272 | int oldrate; |
Mattias Nissler | 1946b74 | 2007-12-20 13:27:26 +0100 | [diff] [blame] | 273 | |
| 274 | #ifdef CONFIG_MAC80211_DEBUGFS |
| 275 | /* Debugfs entries created for the parameters above. */ |
| 276 | struct rc_pid_debugfs_entries dentries; |
| 277 | #endif |
Mattias Nissler | 12446c6 | 2007-12-19 01:27:18 +0100 | [diff] [blame] | 278 | }; |
| 279 | |
| 280 | #endif /* RC80211_PID_H */ |