blob: a849b745bdb56b6f83b19a98e73f069f42341621 [file] [log] [blame]
Mattias Nisslerad018372007-12-19 01:25:57 +01001/*
2 * Copyright 2002-2005, Instant802 Networks, Inc.
3 * Copyright 2005, Devicescape Software, Inc.
4 * Copyright 2007, Mattias Nissler <mattias.nissler@gmx.de>
Stefano Briviob7c50de92008-01-29 20:29:16 +01005 * Copyright 2007-2008, Stefano Brivio <stefano.brivio@polimi.it>
Mattias Nisslerad018372007-12-19 01:25:57 +01006 *
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>
Johannes Berg4b475892008-01-02 15:17:03 +010015#include <linux/debugfs.h>
Mattias Nisslerad018372007-12-19 01:25:57 +010016#include <net/mac80211.h>
Johannes Berg2c8dccc2008-04-08 15:14:40 -040017#include "rate.h"
Luis Carlos Coboee385852008-02-23 15:17:11 +010018#include "mesh.h"
Mattias Nissler12446c62007-12-19 01:27:18 +010019#include "rc80211_pid.h"
20
Mattias Nisslerad018372007-12-19 01:25:57 +010021
22/* This is an implementation of a TX rate control algorithm that uses a PID
23 * controller. Given a target failed frames rate, the controller decides about
24 * TX rate changes to meet the target failed frames rate.
25 *
26 * The controller basically computes the following:
27 *
Stefano Brivio1dc4d1e2007-12-19 01:26:52 +010028 * adj = CP * err + CI * err_avg + CD * (err - last_err) * (1 + sharpening)
Mattias Nisslerad018372007-12-19 01:25:57 +010029 *
30 * where
31 * adj adjustment value that is used to switch TX rate (see below)
32 * err current error: target vs. current failed frames percentage
33 * last_err last error
34 * err_avg average (i.e. poor man's integral) of recent errors
Stefano Brivio1dc4d1e2007-12-19 01:26:52 +010035 * sharpening non-zero when fast response is needed (i.e. right after
36 * association or no frames sent for a long time), heading
37 * to zero over time
Mattias Nisslerad018372007-12-19 01:25:57 +010038 * CP Proportional coefficient
39 * CI Integral coefficient
40 * CD Derivative coefficient
41 *
42 * CP, CI, CD are subject to careful tuning.
43 *
44 * The integral component uses a exponential moving average approach instead of
45 * an actual sliding window. The advantage is that we don't need to keep an
46 * array of the last N error values and computation is easier.
47 *
Stefano Brivio90d501d2007-12-19 01:26:34 +010048 * Once we have the adj value, we map it to a rate by means of a learning
49 * algorithm. This algorithm keeps the state of the percentual failed frames
50 * difference between rates. The behaviour of the lowest available rate is kept
51 * as a reference value, and every time we switch between two rates, we compute
52 * the difference between the failed frames each rate exhibited. By doing so,
53 * we compare behaviours which different rates exhibited in adjacent timeslices,
54 * thus the comparison is minimally affected by external conditions. This
55 * difference gets propagated to the whole set of measurements, so that the
56 * reference is always the same. Periodically, we normalize this set so that
57 * recent events weigh the most. By comparing the adj value with this set, we
58 * avoid pejorative switches to lower rates and allow for switches to higher
59 * rates if they behaved well.
Mattias Nisslerad018372007-12-19 01:25:57 +010060 *
61 * Note that for the computations we use a fixed-point representation to avoid
62 * floating point arithmetic. Hence, all values are shifted left by
63 * RC_PID_ARITH_SHIFT.
64 */
65
Mattias Nisslerad018372007-12-19 01:25:57 +010066
Stefano Briviob7c50de92008-01-29 20:29:16 +010067/* Adjust the rate while ensuring that we won't switch to a lower rate if it
68 * exhibited a worse failed frames behaviour and we'll choose the highest rate
69 * whose failed frames behaviour is not worse than the one of the original rate
70 * target. While at it, check that the new rate is valid. */
Mattias Nisslerad018372007-12-19 01:25:57 +010071static void rate_control_pid_adjust_rate(struct ieee80211_local *local,
Stefano Brivio90d501d2007-12-19 01:26:34 +010072 struct sta_info *sta, int adj,
73 struct rc_pid_rateinfo *rinfo)
Mattias Nisslerad018372007-12-19 01:25:57 +010074{
75 struct ieee80211_sub_if_data *sdata;
Johannes Berg8318d782008-01-24 19:38:38 +010076 struct ieee80211_supported_band *sband;
Stefano Briviob7c50de92008-01-29 20:29:16 +010077 int cur_sorted, new_sorted, probe, tmp, n_bitrates, band;
78 int cur = sta->txrate_idx;
Mattias Nisslerad018372007-12-19 01:25:57 +010079
Johannes Bergd0709a62008-02-25 16:27:46 +010080 sdata = sta->sdata;
Johannes Berg8318d782008-01-24 19:38:38 +010081 sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
Stefano Briviob7c50de92008-01-29 20:29:16 +010082 band = sband->band;
83 n_bitrates = sband->n_bitrates;
Mattias Nisslerad018372007-12-19 01:25:57 +010084
Stefano Briviob7c50de92008-01-29 20:29:16 +010085 /* Map passed arguments to sorted values. */
86 cur_sorted = rinfo[cur].rev_index;
87 new_sorted = cur_sorted + adj;
Mattias Nisslerad018372007-12-19 01:25:57 +010088
Stefano Briviob7c50de92008-01-29 20:29:16 +010089 /* Check limits. */
90 if (new_sorted < 0)
91 new_sorted = rinfo[0].rev_index;
92 else if (new_sorted >= n_bitrates)
93 new_sorted = rinfo[n_bitrates - 1].rev_index;
94
95 tmp = new_sorted;
96
97 if (adj < 0) {
98 /* Ensure that the rate decrease isn't disadvantageous. */
99 for (probe = cur_sorted; probe >= new_sorted; probe--)
100 if (rinfo[probe].diff <= rinfo[cur_sorted].diff &&
101 rate_supported(sta, band, rinfo[probe].index))
102 tmp = probe;
103 } else {
104 /* Look for rate increase with zero (or below) cost. */
105 for (probe = new_sorted + 1; probe < n_bitrates; probe++)
106 if (rinfo[probe].diff <= rinfo[new_sorted].diff &&
107 rate_supported(sta, band, rinfo[probe].index))
108 tmp = probe;
109 }
110
111 /* Fit the rate found to the nearest supported rate. */
112 do {
113 if (rate_supported(sta, band, rinfo[tmp].index)) {
114 sta->txrate_idx = rinfo[tmp].index;
Mattias Nisslerad018372007-12-19 01:25:57 +0100115 break;
116 }
Stefano Briviob7c50de92008-01-29 20:29:16 +0100117 if (adj < 0)
118 tmp--;
119 else
120 tmp++;
121 } while (tmp < n_bitrates && tmp >= 0);
Mattias Nissler12446c62007-12-19 01:27:18 +0100122
123#ifdef CONFIG_MAC80211_DEBUGFS
124 rate_control_pid_event_rate_change(
125 &((struct rc_pid_sta_info *)sta->rate_ctrl_priv)->events,
Stefano Briviob7c50de92008-01-29 20:29:16 +0100126 sta->txrate_idx, sband->bitrates[sta->txrate_idx].bitrate);
Mattias Nissler12446c62007-12-19 01:27:18 +0100127#endif
Mattias Nisslerad018372007-12-19 01:25:57 +0100128}
129
Stefano Brivio90d501d2007-12-19 01:26:34 +0100130/* Normalize the failed frames per-rate differences. */
Mattias Nissler1946b742007-12-20 13:27:26 +0100131static void rate_control_pid_normalize(struct rc_pid_info *pinfo, int l)
Stefano Brivio90d501d2007-12-19 01:26:34 +0100132{
Mattias Nissler1946b742007-12-20 13:27:26 +0100133 int i, norm_offset = pinfo->norm_offset;
134 struct rc_pid_rateinfo *r = pinfo->rinfo;
Stefano Brivio90d501d2007-12-19 01:26:34 +0100135
Mattias Nissler1946b742007-12-20 13:27:26 +0100136 if (r[0].diff > norm_offset)
137 r[0].diff -= norm_offset;
138 else if (r[0].diff < -norm_offset)
139 r[0].diff += norm_offset;
Stefano Brivio90d501d2007-12-19 01:26:34 +0100140 for (i = 0; i < l - 1; i++)
Mattias Nissler1946b742007-12-20 13:27:26 +0100141 if (r[i + 1].diff > r[i].diff + norm_offset)
142 r[i + 1].diff -= norm_offset;
Stefano Brivio90d501d2007-12-19 01:26:34 +0100143 else if (r[i + 1].diff <= r[i].diff)
Mattias Nissler1946b742007-12-20 13:27:26 +0100144 r[i + 1].diff += norm_offset;
Stefano Brivio90d501d2007-12-19 01:26:34 +0100145}
146
Mattias Nisslerad018372007-12-19 01:25:57 +0100147static void rate_control_pid_sample(struct rc_pid_info *pinfo,
148 struct ieee80211_local *local,
149 struct sta_info *sta)
150{
Luis Carlos Coboee385852008-02-23 15:17:11 +0100151#ifdef CONFIG_MAC80211_MESH
Johannes Bergd0709a62008-02-25 16:27:46 +0100152 struct ieee80211_sub_if_data *sdata = sta->sdata;
Luis Carlos Coboee385852008-02-23 15:17:11 +0100153#endif
Mattias Nisslerad018372007-12-19 01:25:57 +0100154 struct rc_pid_sta_info *spinfo = sta->rate_ctrl_priv;
Stefano Brivio90d501d2007-12-19 01:26:34 +0100155 struct rc_pid_rateinfo *rinfo = pinfo->rinfo;
Johannes Berg8318d782008-01-24 19:38:38 +0100156 struct ieee80211_supported_band *sband;
Mattias Nisslerad018372007-12-19 01:25:57 +0100157 u32 pf;
158 s32 err_avg;
Mattias Nissler1946b742007-12-20 13:27:26 +0100159 u32 err_prop;
160 u32 err_int;
161 u32 err_der;
Stefano Brivio90d501d2007-12-19 01:26:34 +0100162 int adj, i, j, tmp;
Mattias Nissler1946b742007-12-20 13:27:26 +0100163 unsigned long period;
Mattias Nisslerad018372007-12-19 01:25:57 +0100164
Johannes Berg8318d782008-01-24 19:38:38 +0100165 sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
Mattias Nisslerad018372007-12-19 01:25:57 +0100166 spinfo = sta->rate_ctrl_priv;
Stefano Brivio1dc4d1e2007-12-19 01:26:52 +0100167
168 /* In case nothing happened during the previous control interval, turn
169 * the sharpening factor on. */
Mattias Nissler1946b742007-12-20 13:27:26 +0100170 period = (HZ * pinfo->sampling_period + 500) / 1000;
171 if (!period)
172 period = 1;
173 if (jiffies - spinfo->last_sample > 2 * period)
174 spinfo->sharp_cnt = pinfo->sharpen_duration;
Stefano Brivio1dc4d1e2007-12-19 01:26:52 +0100175
Mattias Nisslerad018372007-12-19 01:25:57 +0100176 spinfo->last_sample = jiffies;
177
Stefano Brivio1dc4d1e2007-12-19 01:26:52 +0100178 /* This should never happen, but in case, we assume the old sample is
Mattias Nisslerad018372007-12-19 01:25:57 +0100179 * still a good measurement and copy it. */
Stefano Brivio1dc4d1e2007-12-19 01:26:52 +0100180 if (unlikely(spinfo->tx_num_xmit == 0))
Mattias Nisslerad018372007-12-19 01:25:57 +0100181 pf = spinfo->last_pf;
182 else {
183 pf = spinfo->tx_num_failed * 100 / spinfo->tx_num_xmit;
Luis Carlos Coboee385852008-02-23 15:17:11 +0100184#ifdef CONFIG_MAC80211_MESH
185 if (pf == 100 &&
186 sdata->vif.type == IEEE80211_IF_TYPE_MESH_POINT)
187 mesh_plink_broken(sta);
188#endif
Mattias Nisslerad018372007-12-19 01:25:57 +0100189 pf <<= RC_PID_ARITH_SHIFT;
Luis Carlos Coboee385852008-02-23 15:17:11 +0100190 sta->fail_avg = ((pf + (spinfo->last_pf << 3)) / 9)
191 >> RC_PID_ARITH_SHIFT;
Mattias Nisslerad018372007-12-19 01:25:57 +0100192 }
193
Stefano Brivio1dc4d1e2007-12-19 01:26:52 +0100194 spinfo->tx_num_xmit = 0;
195 spinfo->tx_num_failed = 0;
196
Stefano Brivio90d501d2007-12-19 01:26:34 +0100197 /* If we just switched rate, update the rate behaviour info. */
Johannes Berg8318d782008-01-24 19:38:38 +0100198 if (pinfo->oldrate != sta->txrate_idx) {
Stefano Brivio90d501d2007-12-19 01:26:34 +0100199
200 i = rinfo[pinfo->oldrate].rev_index;
Johannes Berg8318d782008-01-24 19:38:38 +0100201 j = rinfo[sta->txrate_idx].rev_index;
Stefano Brivio90d501d2007-12-19 01:26:34 +0100202
203 tmp = (pf - spinfo->last_pf);
204 tmp = RC_PID_DO_ARITH_RIGHT_SHIFT(tmp, RC_PID_ARITH_SHIFT);
205
206 rinfo[j].diff = rinfo[i].diff + tmp;
Johannes Berg8318d782008-01-24 19:38:38 +0100207 pinfo->oldrate = sta->txrate_idx;
Stefano Brivio90d501d2007-12-19 01:26:34 +0100208 }
Johannes Berg8318d782008-01-24 19:38:38 +0100209 rate_control_pid_normalize(pinfo, sband->n_bitrates);
Stefano Brivio90d501d2007-12-19 01:26:34 +0100210
Mattias Nisslerad018372007-12-19 01:25:57 +0100211 /* Compute the proportional, integral and derivative errors. */
Stefano Brivio426706c2007-12-23 04:39:17 +0100212 err_prop = (pinfo->target << RC_PID_ARITH_SHIFT) - pf;
Mattias Nisslerad018372007-12-19 01:25:57 +0100213
Mattias Nissler1946b742007-12-20 13:27:26 +0100214 err_avg = spinfo->err_avg_sc >> pinfo->smoothing_shift;
Mattias Nisslerad018372007-12-19 01:25:57 +0100215 spinfo->err_avg_sc = spinfo->err_avg_sc - err_avg + err_prop;
Mattias Nissler1946b742007-12-20 13:27:26 +0100216 err_int = spinfo->err_avg_sc >> pinfo->smoothing_shift;
Mattias Nisslerad018372007-12-19 01:25:57 +0100217
Mattias Nissler1946b742007-12-20 13:27:26 +0100218 err_der = (pf - spinfo->last_pf) *
219 (1 + pinfo->sharpen_factor * spinfo->sharp_cnt);
Mattias Nisslerad018372007-12-19 01:25:57 +0100220 spinfo->last_pf = pf;
Stefano Brivio1dc4d1e2007-12-19 01:26:52 +0100221 if (spinfo->sharp_cnt)
222 spinfo->sharp_cnt--;
Mattias Nisslerad018372007-12-19 01:25:57 +0100223
Mattias Nissler12446c62007-12-19 01:27:18 +0100224#ifdef CONFIG_MAC80211_DEBUGFS
225 rate_control_pid_event_pf_sample(&spinfo->events, pf, err_prop, err_int,
226 err_der);
227#endif
228
Mattias Nisslerad018372007-12-19 01:25:57 +0100229 /* Compute the controller output. */
230 adj = (err_prop * pinfo->coeff_p + err_int * pinfo->coeff_i
231 + err_der * pinfo->coeff_d);
Stefano Brivio90d501d2007-12-19 01:26:34 +0100232 adj = RC_PID_DO_ARITH_RIGHT_SHIFT(adj, 2 * RC_PID_ARITH_SHIFT);
Mattias Nisslerad018372007-12-19 01:25:57 +0100233
234 /* Change rate. */
235 if (adj)
Stefano Brivio90d501d2007-12-19 01:26:34 +0100236 rate_control_pid_adjust_rate(local, sta, adj, rinfo);
Mattias Nisslerad018372007-12-19 01:25:57 +0100237}
238
239static void rate_control_pid_tx_status(void *priv, struct net_device *dev,
240 struct sk_buff *skb,
241 struct ieee80211_tx_status *status)
242{
243 struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
244 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
Andrew Lutomirskidf26e7e2008-01-03 21:05:37 -0800245 struct ieee80211_sub_if_data *sdata;
Mattias Nisslerad018372007-12-19 01:25:57 +0100246 struct rc_pid_info *pinfo = priv;
247 struct sta_info *sta;
248 struct rc_pid_sta_info *spinfo;
Mattias Nissler1946b742007-12-20 13:27:26 +0100249 unsigned long period;
Johannes Berg8318d782008-01-24 19:38:38 +0100250 struct ieee80211_supported_band *sband;
Mattias Nisslerad018372007-12-19 01:25:57 +0100251
Johannes Bergd0709a62008-02-25 16:27:46 +0100252 rcu_read_lock();
253
Mattias Nisslerad018372007-12-19 01:25:57 +0100254 sta = sta_info_get(local, hdr->addr1);
Johannes Berg8318d782008-01-24 19:38:38 +0100255 sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
Mattias Nisslerad018372007-12-19 01:25:57 +0100256
257 if (!sta)
Johannes Bergd0709a62008-02-25 16:27:46 +0100258 goto unlock;
Mattias Nisslerad018372007-12-19 01:25:57 +0100259
Andrew Lutomirskidf26e7e2008-01-03 21:05:37 -0800260 /* Don't update the state if we're not controlling the rate. */
Johannes Bergd0709a62008-02-25 16:27:46 +0100261 sdata = sta->sdata;
Andrew Lutomirskidf26e7e2008-01-03 21:05:37 -0800262 if (sdata->bss && sdata->bss->force_unicast_rateidx > -1) {
Johannes Berg8318d782008-01-24 19:38:38 +0100263 sta->txrate_idx = sdata->bss->max_ratectrl_rateidx;
Johannes Bergd0709a62008-02-25 16:27:46 +0100264 goto unlock;
Andrew Lutomirskidf26e7e2008-01-03 21:05:37 -0800265 }
266
Mattias Nisslerad018372007-12-19 01:25:57 +0100267 /* Ignore all frames that were sent with a different rate than the rate
268 * we currently advise mac80211 to use. */
Johannes Berg8318d782008-01-24 19:38:38 +0100269 if (status->control.tx_rate != &sband->bitrates[sta->txrate_idx])
Johannes Bergd0709a62008-02-25 16:27:46 +0100270 goto unlock;
Mattias Nisslerad018372007-12-19 01:25:57 +0100271
272 spinfo = sta->rate_ctrl_priv;
273 spinfo->tx_num_xmit++;
274
Mattias Nissler12446c62007-12-19 01:27:18 +0100275#ifdef CONFIG_MAC80211_DEBUGFS
276 rate_control_pid_event_tx_status(&spinfo->events, status);
277#endif
278
Mattias Nisslerad018372007-12-19 01:25:57 +0100279 /* We count frames that totally failed to be transmitted as two bad
280 * frames, those that made it out but had some retries as one good and
281 * one bad frame. */
282 if (status->excessive_retries) {
283 spinfo->tx_num_failed += 2;
284 spinfo->tx_num_xmit++;
285 } else if (status->retry_count) {
286 spinfo->tx_num_failed++;
287 spinfo->tx_num_xmit++;
288 }
289
290 if (status->excessive_retries) {
291 sta->tx_retry_failed++;
292 sta->tx_num_consecutive_failures++;
293 sta->tx_num_mpdu_fail++;
294 } else {
Mattias Nisslerad018372007-12-19 01:25:57 +0100295 sta->tx_num_consecutive_failures = 0;
296 sta->tx_num_mpdu_ok++;
297 }
298 sta->tx_retry_count += status->retry_count;
299 sta->tx_num_mpdu_fail += status->retry_count;
300
301 /* Update PID controller state. */
Mattias Nissler1946b742007-12-20 13:27:26 +0100302 period = (HZ * pinfo->sampling_period + 500) / 1000;
303 if (!period)
304 period = 1;
305 if (time_after(jiffies, spinfo->last_sample + period))
Mattias Nisslerad018372007-12-19 01:25:57 +0100306 rate_control_pid_sample(pinfo, local, sta);
307
Johannes Bergd0709a62008-02-25 16:27:46 +0100308 unlock:
309 rcu_read_unlock();
Mattias Nisslerad018372007-12-19 01:25:57 +0100310}
311
312static void rate_control_pid_get_rate(void *priv, struct net_device *dev,
Johannes Berg8318d782008-01-24 19:38:38 +0100313 struct ieee80211_supported_band *sband,
Mattias Nisslerad018372007-12-19 01:25:57 +0100314 struct sk_buff *skb,
315 struct rate_selection *sel)
316{
317 struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
318 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
Michael Wu2bc454b2007-12-25 19:33:16 -0500319 struct ieee80211_sub_if_data *sdata;
Mattias Nisslerad018372007-12-19 01:25:57 +0100320 struct sta_info *sta;
321 int rateidx;
Michael Wu2bc454b2007-12-25 19:33:16 -0500322 u16 fc;
Mattias Nisslerad018372007-12-19 01:25:57 +0100323
Johannes Bergd0709a62008-02-25 16:27:46 +0100324 rcu_read_lock();
325
Mattias Nisslerad018372007-12-19 01:25:57 +0100326 sta = sta_info_get(local, hdr->addr1);
327
Michael Wu2bc454b2007-12-25 19:33:16 -0500328 /* Send management frames and broadcast/multicast data using lowest
329 * rate. */
330 fc = le16_to_cpu(hdr->frame_control);
331 if ((fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA ||
332 is_multicast_ether_addr(hdr->addr1) || !sta) {
Johannes Berg8318d782008-01-24 19:38:38 +0100333 sel->rate = rate_lowest(local, sband, sta);
Johannes Bergd0709a62008-02-25 16:27:46 +0100334 rcu_read_unlock();
Mattias Nisslerad018372007-12-19 01:25:57 +0100335 return;
336 }
337
Michael Wu2bc454b2007-12-25 19:33:16 -0500338 /* If a forced rate is in effect, select it. */
339 sdata = IEEE80211_DEV_TO_SUB_IF(dev);
340 if (sdata->bss && sdata->bss->force_unicast_rateidx > -1)
Johannes Berg8318d782008-01-24 19:38:38 +0100341 sta->txrate_idx = sdata->bss->force_unicast_rateidx;
Michael Wu2bc454b2007-12-25 19:33:16 -0500342
Johannes Berg8318d782008-01-24 19:38:38 +0100343 rateidx = sta->txrate_idx;
Mattias Nisslerad018372007-12-19 01:25:57 +0100344
Johannes Berg8318d782008-01-24 19:38:38 +0100345 if (rateidx >= sband->n_bitrates)
346 rateidx = sband->n_bitrates - 1;
Mattias Nisslerad018372007-12-19 01:25:57 +0100347
Johannes Berg8318d782008-01-24 19:38:38 +0100348 sta->last_txrate_idx = rateidx;
Michael Wu2bc454b2007-12-25 19:33:16 -0500349
Johannes Bergd0709a62008-02-25 16:27:46 +0100350 rcu_read_unlock();
Mattias Nisslerad018372007-12-19 01:25:57 +0100351
Johannes Berg8318d782008-01-24 19:38:38 +0100352 sel->rate = &sband->bitrates[rateidx];
Mattias Nissler12446c62007-12-19 01:27:18 +0100353
354#ifdef CONFIG_MAC80211_DEBUGFS
355 rate_control_pid_event_tx_rate(
356 &((struct rc_pid_sta_info *) sta->rate_ctrl_priv)->events,
Johannes Berg8318d782008-01-24 19:38:38 +0100357 rateidx, sband->bitrates[rateidx].bitrate);
Mattias Nissler12446c62007-12-19 01:27:18 +0100358#endif
Mattias Nisslerad018372007-12-19 01:25:57 +0100359}
360
361static void rate_control_pid_rate_init(void *priv, void *priv_sta,
362 struct ieee80211_local *local,
363 struct sta_info *sta)
364{
365 /* TODO: This routine should consider using RSSI from previous packets
366 * as we need to have IEEE 802.1X auth succeed immediately after assoc..
367 * Until that method is implemented, we will use the lowest supported
368 * rate as a workaround. */
Johannes Berg8318d782008-01-24 19:38:38 +0100369 struct ieee80211_supported_band *sband;
370
371 sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
372 sta->txrate_idx = rate_lowest_index(local, sband, sta);
Luis Carlos Coboee385852008-02-23 15:17:11 +0100373 sta->fail_avg = 0;
Mattias Nisslerad018372007-12-19 01:25:57 +0100374}
375
376static void *rate_control_pid_alloc(struct ieee80211_local *local)
377{
378 struct rc_pid_info *pinfo;
Stefano Brivio90d501d2007-12-19 01:26:34 +0100379 struct rc_pid_rateinfo *rinfo;
Johannes Berg8318d782008-01-24 19:38:38 +0100380 struct ieee80211_supported_band *sband;
Stefano Brivio90d501d2007-12-19 01:26:34 +0100381 int i, j, tmp;
382 bool s;
Mattias Nissler1946b742007-12-20 13:27:26 +0100383#ifdef CONFIG_MAC80211_DEBUGFS
384 struct rc_pid_debugfs_entries *de;
385#endif
Mattias Nisslerad018372007-12-19 01:25:57 +0100386
Johannes Berg8318d782008-01-24 19:38:38 +0100387 sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
388
Mattias Nisslerad018372007-12-19 01:25:57 +0100389 pinfo = kmalloc(sizeof(*pinfo), GFP_ATOMIC);
Stefano Brivio90d501d2007-12-19 01:26:34 +0100390 if (!pinfo)
391 return NULL;
392
Johannes Berg8318d782008-01-24 19:38:38 +0100393 /* We can safely assume that sband won't change unless we get
Stefano Brivio90d501d2007-12-19 01:26:34 +0100394 * reinitialized. */
Johannes Berg8318d782008-01-24 19:38:38 +0100395 rinfo = kmalloc(sizeof(*rinfo) * sband->n_bitrates, GFP_ATOMIC);
Stefano Brivio90d501d2007-12-19 01:26:34 +0100396 if (!rinfo) {
397 kfree(pinfo);
398 return NULL;
399 }
400
401 /* Sort the rates. This is optimized for the most common case (i.e.
402 * almost-sorted CCK+OFDM rates). Kind of bubble-sort with reversed
403 * mapping too. */
Johannes Berg8318d782008-01-24 19:38:38 +0100404 for (i = 0; i < sband->n_bitrates; i++) {
Stefano Brivio90d501d2007-12-19 01:26:34 +0100405 rinfo[i].index = i;
406 rinfo[i].rev_index = i;
Mattias Nissler1946b742007-12-20 13:27:26 +0100407 if (pinfo->fast_start)
Stefano Brivio90d501d2007-12-19 01:26:34 +0100408 rinfo[i].diff = 0;
409 else
Mattias Nissler1946b742007-12-20 13:27:26 +0100410 rinfo[i].diff = i * pinfo->norm_offset;
Stefano Brivio90d501d2007-12-19 01:26:34 +0100411 }
Johannes Berg8318d782008-01-24 19:38:38 +0100412 for (i = 1; i < sband->n_bitrates; i++) {
Stefano Brivio90d501d2007-12-19 01:26:34 +0100413 s = 0;
Johannes Berg8318d782008-01-24 19:38:38 +0100414 for (j = 0; j < sband->n_bitrates - i; j++)
415 if (unlikely(sband->bitrates[rinfo[j].index].bitrate >
416 sband->bitrates[rinfo[j + 1].index].bitrate)) {
Stefano Brivio90d501d2007-12-19 01:26:34 +0100417 tmp = rinfo[j].index;
418 rinfo[j].index = rinfo[j + 1].index;
419 rinfo[j + 1].index = tmp;
420 rinfo[rinfo[j].index].rev_index = j;
421 rinfo[rinfo[j + 1].index].rev_index = j + 1;
422 s = 1;
423 }
424 if (!s)
425 break;
426 }
Mattias Nisslerad018372007-12-19 01:25:57 +0100427
428 pinfo->target = RC_PID_TARGET_PF;
Mattias Nissler1946b742007-12-20 13:27:26 +0100429 pinfo->sampling_period = RC_PID_INTERVAL;
Mattias Nisslerad018372007-12-19 01:25:57 +0100430 pinfo->coeff_p = RC_PID_COEFF_P;
431 pinfo->coeff_i = RC_PID_COEFF_I;
432 pinfo->coeff_d = RC_PID_COEFF_D;
Mattias Nissler1946b742007-12-20 13:27:26 +0100433 pinfo->smoothing_shift = RC_PID_SMOOTHING_SHIFT;
434 pinfo->sharpen_factor = RC_PID_SHARPENING_FACTOR;
435 pinfo->sharpen_duration = RC_PID_SHARPENING_DURATION;
436 pinfo->norm_offset = RC_PID_NORM_OFFSET;
437 pinfo->fast_start = RC_PID_FAST_START;
Stefano Brivio90d501d2007-12-19 01:26:34 +0100438 pinfo->rinfo = rinfo;
439 pinfo->oldrate = 0;
Mattias Nisslerad018372007-12-19 01:25:57 +0100440
Mattias Nissler1946b742007-12-20 13:27:26 +0100441#ifdef CONFIG_MAC80211_DEBUGFS
442 de = &pinfo->dentries;
443 de->dir = debugfs_create_dir("rc80211_pid",
444 local->hw.wiphy->debugfsdir);
445 de->target = debugfs_create_u32("target_pf", S_IRUSR | S_IWUSR,
446 de->dir, &pinfo->target);
447 de->sampling_period = debugfs_create_u32("sampling_period",
448 S_IRUSR | S_IWUSR, de->dir,
449 &pinfo->sampling_period);
450 de->coeff_p = debugfs_create_u32("coeff_p", S_IRUSR | S_IWUSR,
451 de->dir, &pinfo->coeff_p);
452 de->coeff_i = debugfs_create_u32("coeff_i", S_IRUSR | S_IWUSR,
453 de->dir, &pinfo->coeff_i);
454 de->coeff_d = debugfs_create_u32("coeff_d", S_IRUSR | S_IWUSR,
455 de->dir, &pinfo->coeff_d);
456 de->smoothing_shift = debugfs_create_u32("smoothing_shift",
457 S_IRUSR | S_IWUSR, de->dir,
458 &pinfo->smoothing_shift);
459 de->sharpen_factor = debugfs_create_u32("sharpen_factor",
460 S_IRUSR | S_IWUSR, de->dir,
461 &pinfo->sharpen_factor);
462 de->sharpen_duration = debugfs_create_u32("sharpen_duration",
463 S_IRUSR | S_IWUSR, de->dir,
464 &pinfo->sharpen_duration);
465 de->norm_offset = debugfs_create_u32("norm_offset",
466 S_IRUSR | S_IWUSR, de->dir,
467 &pinfo->norm_offset);
468 de->fast_start = debugfs_create_bool("fast_start",
469 S_IRUSR | S_IWUSR, de->dir,
470 &pinfo->fast_start);
471#endif
472
Mattias Nisslerad018372007-12-19 01:25:57 +0100473 return pinfo;
474}
475
476static void rate_control_pid_free(void *priv)
477{
478 struct rc_pid_info *pinfo = priv;
Mattias Nissler1946b742007-12-20 13:27:26 +0100479#ifdef CONFIG_MAC80211_DEBUGFS
480 struct rc_pid_debugfs_entries *de = &pinfo->dentries;
481
482 debugfs_remove(de->fast_start);
483 debugfs_remove(de->norm_offset);
484 debugfs_remove(de->sharpen_duration);
485 debugfs_remove(de->sharpen_factor);
486 debugfs_remove(de->smoothing_shift);
487 debugfs_remove(de->coeff_d);
488 debugfs_remove(de->coeff_i);
489 debugfs_remove(de->coeff_p);
490 debugfs_remove(de->sampling_period);
491 debugfs_remove(de->target);
492 debugfs_remove(de->dir);
493#endif
494
Stefano Brivio90d501d2007-12-19 01:26:34 +0100495 kfree(pinfo->rinfo);
Mattias Nisslerad018372007-12-19 01:25:57 +0100496 kfree(pinfo);
497}
498
499static void rate_control_pid_clear(void *priv)
500{
501}
502
503static void *rate_control_pid_alloc_sta(void *priv, gfp_t gfp)
504{
505 struct rc_pid_sta_info *spinfo;
506
507 spinfo = kzalloc(sizeof(*spinfo), gfp);
Mattias Nissler12446c62007-12-19 01:27:18 +0100508 if (spinfo == NULL)
509 return NULL;
510
Stefano Brivioc09c7232008-01-17 00:38:29 +0100511 spinfo->last_sample = jiffies;
512
Mattias Nissler12446c62007-12-19 01:27:18 +0100513#ifdef CONFIG_MAC80211_DEBUGFS
514 spin_lock_init(&spinfo->events.lock);
515 init_waitqueue_head(&spinfo->events.waitqueue);
516#endif
Mattias Nisslerad018372007-12-19 01:25:57 +0100517
518 return spinfo;
519}
520
521static void rate_control_pid_free_sta(void *priv, void *priv_sta)
522{
523 struct rc_pid_sta_info *spinfo = priv_sta;
524 kfree(spinfo);
525}
526
Johannes Berg4b475892008-01-02 15:17:03 +0100527static struct rate_control_ops mac80211_rcpid = {
Mattias Nisslerad018372007-12-19 01:25:57 +0100528 .name = "pid",
529 .tx_status = rate_control_pid_tx_status,
530 .get_rate = rate_control_pid_get_rate,
531 .rate_init = rate_control_pid_rate_init,
532 .clear = rate_control_pid_clear,
533 .alloc = rate_control_pid_alloc,
534 .free = rate_control_pid_free,
535 .alloc_sta = rate_control_pid_alloc_sta,
536 .free_sta = rate_control_pid_free_sta,
Mattias Nissler12446c62007-12-19 01:27:18 +0100537#ifdef CONFIG_MAC80211_DEBUGFS
538 .add_sta_debugfs = rate_control_pid_add_sta_debugfs,
539 .remove_sta_debugfs = rate_control_pid_remove_sta_debugfs,
540#endif
Mattias Nisslerad018372007-12-19 01:25:57 +0100541};
Johannes Berg4b475892008-01-02 15:17:03 +0100542
543MODULE_DESCRIPTION("PID controller based rate control algorithm");
544MODULE_AUTHOR("Stefano Brivio");
545MODULE_AUTHOR("Mattias Nissler");
546MODULE_LICENSE("GPL");
547
548int __init rc80211_pid_init(void)
549{
550 return ieee80211_rate_control_register(&mac80211_rcpid);
551}
552
Johannes Bergf0b92052008-01-31 19:31:57 +0100553void rc80211_pid_exit(void)
Johannes Berg4b475892008-01-02 15:17:03 +0100554{
555 ieee80211_rate_control_unregister(&mac80211_rcpid);
556}
557
558#ifdef CONFIG_MAC80211_RC_PID_MODULE
559module_init(rc80211_pid_init);
560module_exit(rc80211_pid_exit);
561#endif