Mattias Nissler | ad01837 | 2007-12-19 01:25:57 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2002-2005, Instant802 Networks, Inc. |
| 3 | * Copyright 2005, Devicescape Software, Inc. |
| 4 | * Copyright 2007, Mattias Nissler <mattias.nissler@gmx.de> |
Stefano Brivio | 90d501d | 2007-12-19 01:26:34 +0100 | [diff] [blame^] | 5 | * Copyright 2007, Stefano Brivio <stefano.brivio@polimi.it> |
Mattias Nissler | ad01837 | 2007-12-19 01:25:57 +0100 | [diff] [blame] | 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License version 2 as |
| 9 | * published by the Free Software Foundation. |
| 10 | */ |
| 11 | |
| 12 | #include <linux/netdevice.h> |
| 13 | #include <linux/types.h> |
| 14 | #include <linux/skbuff.h> |
| 15 | |
| 16 | #include <net/mac80211.h> |
| 17 | #include "ieee80211_rate.h" |
| 18 | |
| 19 | |
| 20 | /* This is an implementation of a TX rate control algorithm that uses a PID |
| 21 | * controller. Given a target failed frames rate, the controller decides about |
| 22 | * TX rate changes to meet the target failed frames rate. |
| 23 | * |
| 24 | * The controller basically computes the following: |
| 25 | * |
| 26 | * adj = CP * err + CI * err_avg + CD * (err - last_err) |
| 27 | * |
| 28 | * where |
| 29 | * adj adjustment value that is used to switch TX rate (see below) |
| 30 | * err current error: target vs. current failed frames percentage |
| 31 | * last_err last error |
| 32 | * err_avg average (i.e. poor man's integral) of recent errors |
| 33 | * CP Proportional coefficient |
| 34 | * CI Integral coefficient |
| 35 | * CD Derivative coefficient |
| 36 | * |
| 37 | * CP, CI, CD are subject to careful tuning. |
| 38 | * |
| 39 | * The integral component uses a exponential moving average approach instead of |
| 40 | * an actual sliding window. The advantage is that we don't need to keep an |
| 41 | * array of the last N error values and computation is easier. |
| 42 | * |
Stefano Brivio | 90d501d | 2007-12-19 01:26:34 +0100 | [diff] [blame^] | 43 | * Once we have the adj value, we map it to a rate by means of a learning |
| 44 | * algorithm. This algorithm keeps the state of the percentual failed frames |
| 45 | * difference between rates. The behaviour of the lowest available rate is kept |
| 46 | * as a reference value, and every time we switch between two rates, we compute |
| 47 | * the difference between the failed frames each rate exhibited. By doing so, |
| 48 | * we compare behaviours which different rates exhibited in adjacent timeslices, |
| 49 | * thus the comparison is minimally affected by external conditions. This |
| 50 | * difference gets propagated to the whole set of measurements, so that the |
| 51 | * reference is always the same. Periodically, we normalize this set so that |
| 52 | * recent events weigh the most. By comparing the adj value with this set, we |
| 53 | * avoid pejorative switches to lower rates and allow for switches to higher |
| 54 | * rates if they behaved well. |
Mattias Nissler | ad01837 | 2007-12-19 01:25:57 +0100 | [diff] [blame] | 55 | * |
| 56 | * Note that for the computations we use a fixed-point representation to avoid |
| 57 | * floating point arithmetic. Hence, all values are shifted left by |
| 58 | * RC_PID_ARITH_SHIFT. |
| 59 | */ |
| 60 | |
| 61 | /* Sampling period for measuring percentage of failed frames. */ |
| 62 | #define RC_PID_INTERVAL (HZ / 8) |
| 63 | |
| 64 | /* Exponential averaging smoothness (used for I part of PID controller) */ |
| 65 | #define RC_PID_SMOOTHING_SHIFT 3 |
| 66 | #define RC_PID_SMOOTHING (1 << RC_PID_SMOOTHING_SHIFT) |
| 67 | |
| 68 | /* Fixed point arithmetic shifting amount. */ |
| 69 | #define RC_PID_ARITH_SHIFT 8 |
| 70 | |
| 71 | /* Fixed point arithmetic factor. */ |
| 72 | #define RC_PID_ARITH_FACTOR (1 << RC_PID_ARITH_SHIFT) |
| 73 | |
| 74 | /* Proportional PID component coefficient. */ |
| 75 | #define RC_PID_COEFF_P 15 |
| 76 | /* Integral PID component coefficient. */ |
| 77 | #define RC_PID_COEFF_I 9 |
| 78 | /* Derivative PID component coefficient. */ |
| 79 | #define RC_PID_COEFF_D 15 |
| 80 | |
| 81 | /* Target failed frames rate for the PID controller. NB: This effectively gives |
| 82 | * maximum failed frames percentage we're willing to accept. If the wireless |
| 83 | * link quality is good, the controller will fail to adjust failed frames |
| 84 | * percentage to the target. This is intentional. |
| 85 | */ |
| 86 | #define RC_PID_TARGET_PF (11 << RC_PID_ARITH_SHIFT) |
| 87 | |
Stefano Brivio | 90d501d | 2007-12-19 01:26:34 +0100 | [diff] [blame^] | 88 | /* Rate behaviour normalization quantity over time. */ |
| 89 | #define RC_PID_NORM_OFFSET 3 |
| 90 | |
| 91 | /* Push high rates right after loading. */ |
| 92 | #define RC_PID_FAST_START 0 |
| 93 | |
| 94 | /* Arithmetic right shift for positive and negative values for ISO C. */ |
| 95 | #define RC_PID_DO_ARITH_RIGHT_SHIFT(x, y) \ |
| 96 | (x) < 0 ? -((-(x)) >> (y)) : (x) >> (y) |
| 97 | |
Mattias Nissler | ad01837 | 2007-12-19 01:25:57 +0100 | [diff] [blame] | 98 | struct rc_pid_sta_info { |
| 99 | unsigned long last_change; |
| 100 | unsigned long last_sample; |
| 101 | |
| 102 | u32 tx_num_failed; |
| 103 | u32 tx_num_xmit; |
| 104 | |
| 105 | /* Average failed frames percentage error (i.e. actual vs. target |
| 106 | * percentage), scaled by RC_PID_SMOOTHING. This value is computed |
| 107 | * using using an exponential weighted average technique: |
| 108 | * |
| 109 | * (RC_PID_SMOOTHING - 1) * err_avg_old + err |
| 110 | * err_avg = ------------------------------------------ |
| 111 | * RC_PID_SMOOTHING |
| 112 | * |
| 113 | * where err_avg is the new approximation, err_avg_old the previous one |
| 114 | * and err is the error w.r.t. to the current failed frames percentage |
| 115 | * sample. Note that the bigger RC_PID_SMOOTHING the more weight is |
| 116 | * given to the previous estimate, resulting in smoother behavior (i.e. |
| 117 | * corresponding to a longer integration window). |
| 118 | * |
| 119 | * For computation, we actually don't use the above formula, but this |
| 120 | * one: |
| 121 | * |
| 122 | * err_avg_scaled = err_avg_old_scaled - err_avg_old + err |
| 123 | * |
| 124 | * where: |
| 125 | * err_avg_scaled = err * RC_PID_SMOOTHING |
| 126 | * err_avg_old_scaled = err_avg_old * RC_PID_SMOOTHING |
| 127 | * |
| 128 | * This avoids floating point numbers and the per_failed_old value can |
| 129 | * easily be obtained by shifting per_failed_old_scaled right by |
| 130 | * RC_PID_SMOOTHING_SHIFT. |
| 131 | */ |
| 132 | s32 err_avg_sc; |
| 133 | |
| 134 | /* Last framed failes percentage sample */ |
| 135 | u32 last_pf; |
| 136 | }; |
| 137 | |
| 138 | /* Algorithm parameters. We keep them on a per-algorithm approach, so they can |
| 139 | * be tuned individually for each interface. |
| 140 | */ |
Stefano Brivio | 90d501d | 2007-12-19 01:26:34 +0100 | [diff] [blame^] | 141 | struct rc_pid_rateinfo { |
| 142 | |
| 143 | /* Map sorted rates to rates in ieee80211_hw_mode. */ |
| 144 | int index; |
| 145 | |
| 146 | /* Map rates in ieee80211_hw_mode to sorted rates. */ |
| 147 | int rev_index; |
| 148 | |
| 149 | /* Comparison with the lowest rate. */ |
| 150 | int diff; |
| 151 | }; |
| 152 | |
Mattias Nissler | ad01837 | 2007-12-19 01:25:57 +0100 | [diff] [blame] | 153 | struct rc_pid_info { |
| 154 | |
| 155 | /* The failed frames percentage target. */ |
| 156 | u32 target; |
| 157 | |
| 158 | /* P, I and D coefficients. */ |
| 159 | s32 coeff_p; |
| 160 | s32 coeff_i; |
| 161 | s32 coeff_d; |
Stefano Brivio | 90d501d | 2007-12-19 01:26:34 +0100 | [diff] [blame^] | 162 | |
| 163 | /* Rates information. */ |
| 164 | struct rc_pid_rateinfo *rinfo; |
| 165 | |
| 166 | /* Index of the last used rate. */ |
| 167 | int oldrate; |
Mattias Nissler | ad01837 | 2007-12-19 01:25:57 +0100 | [diff] [blame] | 168 | }; |
| 169 | |
Stefano Brivio | 90d501d | 2007-12-19 01:26:34 +0100 | [diff] [blame^] | 170 | /* Shift the adjustment so that we won't switch to a lower rate if it exhibited |
| 171 | * a worse failed frames behaviour and we'll choose the highest rate whose |
| 172 | * failed frames behaviour is not worse than the one of the original rate |
| 173 | * target. While at it, check that the adjustment is within the ranges. Then, |
| 174 | * provide the new rate index. */ |
| 175 | static int rate_control_pid_shift_adjust(struct rc_pid_rateinfo *r, |
| 176 | int adj, int cur, int l) |
| 177 | { |
| 178 | int i, j, k, tmp; |
| 179 | |
| 180 | if (cur + adj < 0) |
| 181 | return 0; |
| 182 | if (cur + adj >= l) |
| 183 | return l - 1; |
| 184 | |
| 185 | i = r[cur + adj].rev_index; |
| 186 | |
| 187 | j = r[cur].rev_index; |
| 188 | |
| 189 | if (adj < 0) { |
| 190 | tmp = i; |
| 191 | for (k = j; k >= i; k--) |
| 192 | if (r[k].diff <= r[j].diff) |
| 193 | tmp = k; |
| 194 | return r[tmp].index; |
| 195 | } else if (adj > 0) { |
| 196 | tmp = i; |
| 197 | for (k = i + 1; k + i < l; k++) |
| 198 | if (r[k].diff <= r[i].diff) |
| 199 | tmp = k; |
| 200 | return r[tmp].index; |
| 201 | } |
| 202 | return cur + adj; |
| 203 | } |
Mattias Nissler | ad01837 | 2007-12-19 01:25:57 +0100 | [diff] [blame] | 204 | |
| 205 | static void rate_control_pid_adjust_rate(struct ieee80211_local *local, |
Stefano Brivio | 90d501d | 2007-12-19 01:26:34 +0100 | [diff] [blame^] | 206 | struct sta_info *sta, int adj, |
| 207 | struct rc_pid_rateinfo *rinfo) |
Mattias Nissler | ad01837 | 2007-12-19 01:25:57 +0100 | [diff] [blame] | 208 | { |
| 209 | struct ieee80211_sub_if_data *sdata; |
| 210 | struct ieee80211_hw_mode *mode; |
Stefano Brivio | 90d501d | 2007-12-19 01:26:34 +0100 | [diff] [blame^] | 211 | int newidx; |
Mattias Nissler | ad01837 | 2007-12-19 01:25:57 +0100 | [diff] [blame] | 212 | int maxrate; |
| 213 | int back = (adj > 0) ? 1 : -1; |
| 214 | |
| 215 | sdata = IEEE80211_DEV_TO_SUB_IF(sta->dev); |
| 216 | if (sdata->bss && sdata->bss->force_unicast_rateidx > -1) { |
| 217 | /* forced unicast rate - do not change STA rate */ |
| 218 | return; |
| 219 | } |
| 220 | |
| 221 | mode = local->oper_hw_mode; |
| 222 | maxrate = sdata->bss ? sdata->bss->max_ratectrl_rateidx : -1; |
| 223 | |
Stefano Brivio | 90d501d | 2007-12-19 01:26:34 +0100 | [diff] [blame^] | 224 | newidx = rate_control_pid_shift_adjust(rinfo, adj, sta->txrate, |
| 225 | mode->num_rates); |
Mattias Nissler | ad01837 | 2007-12-19 01:25:57 +0100 | [diff] [blame] | 226 | |
| 227 | while (newidx != sta->txrate) { |
| 228 | if (rate_supported(sta, mode, newidx) && |
| 229 | (maxrate < 0 || newidx <= maxrate)) { |
| 230 | sta->txrate = newidx; |
| 231 | break; |
| 232 | } |
| 233 | |
| 234 | newidx += back; |
| 235 | } |
| 236 | } |
| 237 | |
Stefano Brivio | 90d501d | 2007-12-19 01:26:34 +0100 | [diff] [blame^] | 238 | /* Normalize the failed frames per-rate differences. */ |
| 239 | static void rate_control_pid_normalize(struct rc_pid_rateinfo *r, int l) |
| 240 | { |
| 241 | int i; |
| 242 | |
| 243 | if (r[0].diff > RC_PID_NORM_OFFSET) |
| 244 | r[0].diff -= RC_PID_NORM_OFFSET; |
| 245 | else if (r[0].diff < -RC_PID_NORM_OFFSET) |
| 246 | r[0].diff += RC_PID_NORM_OFFSET; |
| 247 | for (i = 0; i < l - 1; i++) |
| 248 | if (r[i + 1].diff > r[i].diff + RC_PID_NORM_OFFSET) |
| 249 | r[i + 1].diff -= RC_PID_NORM_OFFSET; |
| 250 | else if (r[i + 1].diff <= r[i].diff) |
| 251 | r[i + 1].diff += RC_PID_NORM_OFFSET; |
| 252 | } |
| 253 | |
Mattias Nissler | ad01837 | 2007-12-19 01:25:57 +0100 | [diff] [blame] | 254 | static void rate_control_pid_sample(struct rc_pid_info *pinfo, |
| 255 | struct ieee80211_local *local, |
| 256 | struct sta_info *sta) |
| 257 | { |
| 258 | struct rc_pid_sta_info *spinfo = sta->rate_ctrl_priv; |
Stefano Brivio | 90d501d | 2007-12-19 01:26:34 +0100 | [diff] [blame^] | 259 | struct rc_pid_rateinfo *rinfo = pinfo->rinfo; |
| 260 | struct ieee80211_hw_mode *mode; |
Mattias Nissler | ad01837 | 2007-12-19 01:25:57 +0100 | [diff] [blame] | 261 | u32 pf; |
| 262 | s32 err_avg; |
| 263 | s32 err_prop; |
| 264 | s32 err_int; |
| 265 | s32 err_der; |
Stefano Brivio | 90d501d | 2007-12-19 01:26:34 +0100 | [diff] [blame^] | 266 | int adj, i, j, tmp; |
Mattias Nissler | ad01837 | 2007-12-19 01:25:57 +0100 | [diff] [blame] | 267 | |
Stefano Brivio | 90d501d | 2007-12-19 01:26:34 +0100 | [diff] [blame^] | 268 | mode = local->oper_hw_mode; |
Mattias Nissler | ad01837 | 2007-12-19 01:25:57 +0100 | [diff] [blame] | 269 | spinfo = sta->rate_ctrl_priv; |
| 270 | spinfo->last_sample = jiffies; |
| 271 | |
| 272 | /* If no frames were transmitted, we assume the old sample is |
| 273 | * still a good measurement and copy it. */ |
| 274 | if (spinfo->tx_num_xmit == 0) |
| 275 | pf = spinfo->last_pf; |
| 276 | else { |
| 277 | pf = spinfo->tx_num_failed * 100 / spinfo->tx_num_xmit; |
| 278 | pf <<= RC_PID_ARITH_SHIFT; |
| 279 | |
| 280 | spinfo->tx_num_xmit = 0; |
| 281 | spinfo->tx_num_failed = 0; |
| 282 | } |
| 283 | |
Stefano Brivio | 90d501d | 2007-12-19 01:26:34 +0100 | [diff] [blame^] | 284 | /* If we just switched rate, update the rate behaviour info. */ |
| 285 | if (pinfo->oldrate != sta->txrate) { |
| 286 | |
| 287 | i = rinfo[pinfo->oldrate].rev_index; |
| 288 | j = rinfo[sta->txrate].rev_index; |
| 289 | |
| 290 | tmp = (pf - spinfo->last_pf); |
| 291 | tmp = RC_PID_DO_ARITH_RIGHT_SHIFT(tmp, RC_PID_ARITH_SHIFT); |
| 292 | |
| 293 | rinfo[j].diff = rinfo[i].diff + tmp; |
| 294 | pinfo->oldrate = sta->txrate; |
| 295 | } |
| 296 | rate_control_pid_normalize(rinfo, mode->num_rates); |
| 297 | |
Mattias Nissler | ad01837 | 2007-12-19 01:25:57 +0100 | [diff] [blame] | 298 | /* Compute the proportional, integral and derivative errors. */ |
| 299 | err_prop = RC_PID_TARGET_PF - pf; |
| 300 | |
| 301 | err_avg = spinfo->err_avg_sc >> RC_PID_SMOOTHING_SHIFT; |
| 302 | spinfo->err_avg_sc = spinfo->err_avg_sc - err_avg + err_prop; |
| 303 | err_int = spinfo->err_avg_sc >> RC_PID_SMOOTHING_SHIFT; |
| 304 | |
| 305 | err_der = pf - spinfo->last_pf; |
| 306 | spinfo->last_pf = pf; |
| 307 | |
| 308 | /* Compute the controller output. */ |
| 309 | adj = (err_prop * pinfo->coeff_p + err_int * pinfo->coeff_i |
| 310 | + err_der * pinfo->coeff_d); |
Stefano Brivio | 90d501d | 2007-12-19 01:26:34 +0100 | [diff] [blame^] | 311 | adj = RC_PID_DO_ARITH_RIGHT_SHIFT(adj, 2 * RC_PID_ARITH_SHIFT); |
Mattias Nissler | ad01837 | 2007-12-19 01:25:57 +0100 | [diff] [blame] | 312 | |
| 313 | /* Change rate. */ |
| 314 | if (adj) |
Stefano Brivio | 90d501d | 2007-12-19 01:26:34 +0100 | [diff] [blame^] | 315 | rate_control_pid_adjust_rate(local, sta, adj, rinfo); |
Mattias Nissler | ad01837 | 2007-12-19 01:25:57 +0100 | [diff] [blame] | 316 | } |
| 317 | |
| 318 | static void rate_control_pid_tx_status(void *priv, struct net_device *dev, |
| 319 | struct sk_buff *skb, |
| 320 | struct ieee80211_tx_status *status) |
| 321 | { |
| 322 | struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr); |
| 323 | struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; |
| 324 | struct rc_pid_info *pinfo = priv; |
| 325 | struct sta_info *sta; |
| 326 | struct rc_pid_sta_info *spinfo; |
| 327 | |
| 328 | sta = sta_info_get(local, hdr->addr1); |
| 329 | |
| 330 | if (!sta) |
| 331 | return; |
| 332 | |
| 333 | /* Ignore all frames that were sent with a different rate than the rate |
| 334 | * we currently advise mac80211 to use. */ |
| 335 | if (status->control.rate != &local->oper_hw_mode->rates[sta->txrate]) |
| 336 | return; |
| 337 | |
| 338 | spinfo = sta->rate_ctrl_priv; |
| 339 | spinfo->tx_num_xmit++; |
| 340 | |
| 341 | /* We count frames that totally failed to be transmitted as two bad |
| 342 | * frames, those that made it out but had some retries as one good and |
| 343 | * one bad frame. */ |
| 344 | if (status->excessive_retries) { |
| 345 | spinfo->tx_num_failed += 2; |
| 346 | spinfo->tx_num_xmit++; |
| 347 | } else if (status->retry_count) { |
| 348 | spinfo->tx_num_failed++; |
| 349 | spinfo->tx_num_xmit++; |
| 350 | } |
| 351 | |
| 352 | if (status->excessive_retries) { |
| 353 | sta->tx_retry_failed++; |
| 354 | sta->tx_num_consecutive_failures++; |
| 355 | sta->tx_num_mpdu_fail++; |
| 356 | } else { |
| 357 | sta->last_ack_rssi[0] = sta->last_ack_rssi[1]; |
| 358 | sta->last_ack_rssi[1] = sta->last_ack_rssi[2]; |
| 359 | sta->last_ack_rssi[2] = status->ack_signal; |
| 360 | sta->tx_num_consecutive_failures = 0; |
| 361 | sta->tx_num_mpdu_ok++; |
| 362 | } |
| 363 | sta->tx_retry_count += status->retry_count; |
| 364 | sta->tx_num_mpdu_fail += status->retry_count; |
| 365 | |
| 366 | /* Update PID controller state. */ |
| 367 | if (time_after(jiffies, spinfo->last_sample + RC_PID_INTERVAL)) |
| 368 | rate_control_pid_sample(pinfo, local, sta); |
| 369 | |
| 370 | sta_info_put(sta); |
| 371 | } |
| 372 | |
| 373 | static void rate_control_pid_get_rate(void *priv, struct net_device *dev, |
| 374 | struct ieee80211_hw_mode *mode, |
| 375 | struct sk_buff *skb, |
| 376 | struct rate_selection *sel) |
| 377 | { |
| 378 | struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr); |
| 379 | struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; |
| 380 | struct sta_info *sta; |
| 381 | int rateidx; |
| 382 | |
| 383 | sta = sta_info_get(local, hdr->addr1); |
| 384 | |
| 385 | if (!sta) { |
| 386 | sel->rate = rate_lowest(local, mode, NULL); |
| 387 | sta_info_put(sta); |
| 388 | return; |
| 389 | } |
| 390 | |
| 391 | rateidx = sta->txrate; |
| 392 | |
| 393 | if (rateidx >= mode->num_rates) |
| 394 | rateidx = mode->num_rates - 1; |
| 395 | |
| 396 | sta_info_put(sta); |
| 397 | |
| 398 | sel->rate = &mode->rates[rateidx]; |
| 399 | } |
| 400 | |
| 401 | static void rate_control_pid_rate_init(void *priv, void *priv_sta, |
| 402 | struct ieee80211_local *local, |
| 403 | struct sta_info *sta) |
| 404 | { |
| 405 | /* TODO: This routine should consider using RSSI from previous packets |
| 406 | * as we need to have IEEE 802.1X auth succeed immediately after assoc.. |
| 407 | * Until that method is implemented, we will use the lowest supported |
| 408 | * rate as a workaround. */ |
| 409 | sta->txrate = rate_lowest_index(local, local->oper_hw_mode, sta); |
| 410 | } |
| 411 | |
| 412 | static void *rate_control_pid_alloc(struct ieee80211_local *local) |
| 413 | { |
| 414 | struct rc_pid_info *pinfo; |
Stefano Brivio | 90d501d | 2007-12-19 01:26:34 +0100 | [diff] [blame^] | 415 | struct rc_pid_rateinfo *rinfo; |
| 416 | struct ieee80211_hw_mode *mode; |
| 417 | int i, j, tmp; |
| 418 | bool s; |
Mattias Nissler | ad01837 | 2007-12-19 01:25:57 +0100 | [diff] [blame] | 419 | |
| 420 | pinfo = kmalloc(sizeof(*pinfo), GFP_ATOMIC); |
Stefano Brivio | 90d501d | 2007-12-19 01:26:34 +0100 | [diff] [blame^] | 421 | if (!pinfo) |
| 422 | return NULL; |
| 423 | |
| 424 | /* We can safely assume that oper_hw_mode won't change unless we get |
| 425 | * reinitialized. */ |
| 426 | mode = local->oper_hw_mode; |
| 427 | rinfo = kmalloc(sizeof(*rinfo) * mode->num_rates, GFP_ATOMIC); |
| 428 | if (!rinfo) { |
| 429 | kfree(pinfo); |
| 430 | return NULL; |
| 431 | } |
| 432 | |
| 433 | /* Sort the rates. This is optimized for the most common case (i.e. |
| 434 | * almost-sorted CCK+OFDM rates). Kind of bubble-sort with reversed |
| 435 | * mapping too. */ |
| 436 | for (i = 0; i < mode->num_rates; i++) { |
| 437 | rinfo[i].index = i; |
| 438 | rinfo[i].rev_index = i; |
| 439 | if (RC_PID_FAST_START) |
| 440 | rinfo[i].diff = 0; |
| 441 | else |
| 442 | rinfo[i].diff = i * RC_PID_NORM_OFFSET; |
| 443 | } |
| 444 | for (i = 1; i < mode->num_rates; i++) { |
| 445 | s = 0; |
| 446 | for (j = 0; j < mode->num_rates - i; j++) |
| 447 | if (unlikely(mode->rates[rinfo[j].index].rate > |
| 448 | mode->rates[rinfo[j + 1].index].rate)) { |
| 449 | tmp = rinfo[j].index; |
| 450 | rinfo[j].index = rinfo[j + 1].index; |
| 451 | rinfo[j + 1].index = tmp; |
| 452 | rinfo[rinfo[j].index].rev_index = j; |
| 453 | rinfo[rinfo[j + 1].index].rev_index = j + 1; |
| 454 | s = 1; |
| 455 | } |
| 456 | if (!s) |
| 457 | break; |
| 458 | } |
Mattias Nissler | ad01837 | 2007-12-19 01:25:57 +0100 | [diff] [blame] | 459 | |
| 460 | pinfo->target = RC_PID_TARGET_PF; |
| 461 | pinfo->coeff_p = RC_PID_COEFF_P; |
| 462 | pinfo->coeff_i = RC_PID_COEFF_I; |
| 463 | pinfo->coeff_d = RC_PID_COEFF_D; |
Stefano Brivio | 90d501d | 2007-12-19 01:26:34 +0100 | [diff] [blame^] | 464 | pinfo->rinfo = rinfo; |
| 465 | pinfo->oldrate = 0; |
Mattias Nissler | ad01837 | 2007-12-19 01:25:57 +0100 | [diff] [blame] | 466 | |
| 467 | return pinfo; |
| 468 | } |
| 469 | |
| 470 | static void rate_control_pid_free(void *priv) |
| 471 | { |
| 472 | struct rc_pid_info *pinfo = priv; |
Stefano Brivio | 90d501d | 2007-12-19 01:26:34 +0100 | [diff] [blame^] | 473 | kfree(pinfo->rinfo); |
Mattias Nissler | ad01837 | 2007-12-19 01:25:57 +0100 | [diff] [blame] | 474 | kfree(pinfo); |
| 475 | } |
| 476 | |
| 477 | static void rate_control_pid_clear(void *priv) |
| 478 | { |
| 479 | } |
| 480 | |
| 481 | static void *rate_control_pid_alloc_sta(void *priv, gfp_t gfp) |
| 482 | { |
| 483 | struct rc_pid_sta_info *spinfo; |
| 484 | |
| 485 | spinfo = kzalloc(sizeof(*spinfo), gfp); |
| 486 | |
| 487 | return spinfo; |
| 488 | } |
| 489 | |
| 490 | static void rate_control_pid_free_sta(void *priv, void *priv_sta) |
| 491 | { |
| 492 | struct rc_pid_sta_info *spinfo = priv_sta; |
| 493 | kfree(spinfo); |
| 494 | } |
| 495 | |
| 496 | struct rate_control_ops mac80211_rcpid = { |
| 497 | .name = "pid", |
| 498 | .tx_status = rate_control_pid_tx_status, |
| 499 | .get_rate = rate_control_pid_get_rate, |
| 500 | .rate_init = rate_control_pid_rate_init, |
| 501 | .clear = rate_control_pid_clear, |
| 502 | .alloc = rate_control_pid_alloc, |
| 503 | .free = rate_control_pid_free, |
| 504 | .alloc_sta = rate_control_pid_alloc_sta, |
| 505 | .free_sta = rate_control_pid_free_sta, |
| 506 | }; |