2 * Copyright (c) 2002-2007 Sam Leffler, Errno Consulting
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
34 * Atsushi Onoe's rate control algorithm.
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/sysctl.h>
43 #include <sys/kernel.h>
45 #include <sys/mutex.h>
46 #include <sys/errno.h>
48 #include <machine/bus.h>
49 #include <machine/resource.h>
52 #include <sys/socket.h>
55 #include <net/if_media.h>
56 #include <net/if_arp.h>
57 #include <net/ethernet.h> /* XXX for ether_sprintf */
59 #include <net80211/ieee80211_var.h>
64 #include <netinet/in.h>
65 #include <netinet/if_ether.h>
68 #include <dev/ath/if_athvar.h>
69 #include <dev/ath/ath_rate/onoe/onoe.h>
70 #include <dev/ath/ath_hal/ah_desc.h>
73 * Default parameters for the rate control algorithm. These are
74 * all tunable with sysctls. The rate controller runs periodically
75 * (each ath_rateinterval ms) analyzing transmit statistics for each
76 * neighbor/station (when operating in station mode this is only the AP).
77 * If transmits look to be working well over a sampling period then
78 * it gives a "raise rate credit". If transmits look to not be working
79 * well than it deducts a credit. If the credits cross a threshold then
80 * the transmit rate is raised. Various error conditions force the
81 * the transmit rate to be dropped.
83 * The decision to issue/deduct a credit is based on the errors and
84 * retries accumulated over the sampling period. ath_rate_raise defines
85 * the percent of retransmits for which a credit is issued/deducted.
86 * ath_rate_raise_threshold defines the threshold on credits at which
87 * the transmit rate is increased.
89 * XXX this algorithm is flawed.
91 static int ath_rateinterval = 1000; /* rate ctl interval (ms) */
92 static int ath_rate_raise = 10; /* add credit threshold */
93 static int ath_rate_raise_threshold = 10; /* rate ctl raise threshold */
95 static void ath_rate_update(struct ath_softc *, struct ieee80211_node *,
97 static void ath_rate_ctl_start(struct ath_softc *, struct ieee80211_node *);
98 static void ath_rate_ctl(void *, struct ieee80211_node *);
101 ath_rate_node_init(struct ath_softc *sc, struct ath_node *an)
103 /* NB: assumed to be zero'd by caller */
107 ath_rate_node_cleanup(struct ath_softc *sc, struct ath_node *an)
112 ath_rate_findrate(struct ath_softc *sc, struct ath_node *an,
113 int shortPreamble, size_t frameLen,
114 u_int8_t *rix, int *try0, u_int8_t *txrate)
116 struct onoe_node *on = ATH_NODE_ONOE(an);
118 *rix = on->on_tx_rix0;
119 *try0 = on->on_tx_try0;
121 *txrate = on->on_tx_rate0sp;
123 *txrate = on->on_tx_rate0;
129 * The short preamble bits aren't set here; the caller should augment
130 * the returned rate with the relevant preamble rate flag.
133 ath_rate_getxtxrates(struct ath_softc *sc, struct ath_node *an,
134 uint8_t rix0, struct ath_rc_series *rc)
136 struct onoe_node *on = ATH_NODE_ONOE(an);
138 rc[0].flags = rc[1].flags = rc[2].flags = rc[3].flags = 0;
140 rc[0].rix = on->on_tx_rate0;
141 rc[1].rix = on->on_tx_rate1;
142 rc[2].rix = on->on_tx_rate2;
143 rc[3].rix = on->on_tx_rate3;
145 rc[0].tries = on->on_tx_try0;
152 ath_rate_setupxtxdesc(struct ath_softc *sc, struct ath_node *an,
153 struct ath_desc *ds, int shortPreamble, u_int8_t rix)
155 struct onoe_node *on = ATH_NODE_ONOE(an);
157 ath_hal_setupxtxdesc(sc->sc_ah, ds
158 , on->on_tx_rate1sp, 2 /* series 1 */
159 , on->on_tx_rate2sp, 2 /* series 2 */
160 , on->on_tx_rate3sp, 2 /* series 3 */
165 ath_rate_tx_complete(struct ath_softc *sc, struct ath_node *an,
166 const struct ath_rc_series *rc, const struct ath_tx_status *ts,
167 int frame_size, int nframes, int nbad)
169 struct onoe_node *on = ATH_NODE_ONOE(an);
171 if (ts->ts_status == 0)
175 on->on_tx_retr += ts->ts_shortretry
177 if (on->on_interval != 0 && ticks - on->on_ticks > on->on_interval) {
178 ath_rate_ctl(sc, &an->an_node);
179 on->on_ticks = ticks;
184 ath_rate_newassoc(struct ath_softc *sc, struct ath_node *an, int isnew)
187 ath_rate_ctl_start(sc, &an->an_node);
191 ath_rate_update(struct ath_softc *sc, struct ieee80211_node *ni, int rate)
193 struct ath_node *an = ATH_NODE(ni);
194 struct onoe_node *on = ATH_NODE_ONOE(an);
195 struct ieee80211vap *vap = ni->ni_vap;
196 const HAL_RATE_TABLE *rt = sc->sc_currates;
199 KASSERT(rt != NULL, ("no rate table, mode %u", sc->sc_curmode));
201 IEEE80211_NOTE(vap, IEEE80211_MSG_RATECTL, ni,
202 "%s: set xmit rate to %dM", __func__,
203 ni->ni_rates.rs_nrates > 0 ?
204 (ni->ni_rates.rs_rates[rate] & IEEE80211_RATE_VAL) / 2 : 0);
207 * Before associating a node has no rate set setup
208 * so we can't calculate any transmit codes to use.
209 * This is ok since we should never be sending anything
210 * but management frames and those always go at the
211 * lowest hardware rate.
213 if (ni->ni_rates.rs_nrates == 0)
216 ni->ni_txrate = ni->ni_rates.rs_rates[rate] & IEEE80211_RATE_VAL;
217 on->on_tx_rix0 = sc->sc_rixmap[ni->ni_txrate];
218 on->on_tx_rate0 = rt->info[on->on_tx_rix0].rateCode;
220 on->on_tx_rate0sp = on->on_tx_rate0 |
221 rt->info[on->on_tx_rix0].shortPreamble;
222 if (sc->sc_mrretry) {
224 * Hardware supports multi-rate retry; setup two
225 * step-down retry rates and make the lowest rate
226 * be the ``last chance''. We use 4, 2, 2, 2 tries
227 * respectively (4 is set here, the rest are fixed
228 * in the xmit routine).
230 on->on_tx_try0 = 1 + 3; /* 4 tries at rate 0 */
233 ni->ni_rates.rs_rates[rate]&IEEE80211_RATE_VAL];
234 on->on_tx_rate1 = rt->info[rix].rateCode;
235 on->on_tx_rate1sp = on->on_tx_rate1 |
236 rt->info[rix].shortPreamble;
238 on->on_tx_rate1 = on->on_tx_rate1sp = 0;
242 ni->ni_rates.rs_rates[rate]&IEEE80211_RATE_VAL];
243 on->on_tx_rate2 = rt->info[rix].rateCode;
244 on->on_tx_rate2sp = on->on_tx_rate2 |
245 rt->info[rix].shortPreamble;
247 on->on_tx_rate2 = on->on_tx_rate2sp = 0;
250 /* NB: only do this if we didn't already do it above */
251 on->on_tx_rate3 = rt->info[0].rateCode;
253 on->on_tx_rate3 | rt->info[0].shortPreamble;
255 on->on_tx_rate3 = on->on_tx_rate3sp = 0;
258 on->on_tx_try0 = ATH_TXMAXTRY; /* max tries at rate 0 */
259 on->on_tx_rate1 = on->on_tx_rate1sp = 0;
260 on->on_tx_rate2 = on->on_tx_rate2sp = 0;
261 on->on_tx_rate3 = on->on_tx_rate3sp = 0;
264 on->on_tx_ok = on->on_tx_err = on->on_tx_retr = on->on_tx_upper = 0;
266 on->on_interval = ath_rateinterval;
267 if (vap->iv_opmode == IEEE80211_M_STA)
268 on->on_interval /= 2;
269 on->on_interval = (on->on_interval * hz) / 1000;
273 * Set the starting transmit rate for a node.
276 ath_rate_ctl_start(struct ath_softc *sc, struct ieee80211_node *ni)
278 #define RATE(_ix) (ni->ni_rates.rs_rates[(_ix)] & IEEE80211_RATE_VAL)
279 const struct ieee80211_txparam *tp = ni->ni_txparms;
282 KASSERT(ni->ni_rates.rs_nrates > 0, ("no rates"));
283 if (tp == NULL || tp->ucastrate == IEEE80211_FIXED_RATE_NONE) {
285 * No fixed rate is requested. For 11b start with
286 * the highest negotiated rate; otherwise, for 11g
287 * and 11a, we start "in the middle" at 24Mb or 36Mb.
289 srate = ni->ni_rates.rs_nrates - 1;
290 if (sc->sc_curmode != IEEE80211_MODE_11B) {
292 * Scan the negotiated rate set to find the
295 /* NB: the rate set is assumed sorted */
296 for (; srate >= 0 && RATE(srate) > 72; srate--)
301 * A fixed rate is to be used; ic_fixed_rate is the
302 * IEEE code for this rate (sans basic bit). Convert this
303 * to the index into the negotiated rate set for
304 * the node. We know the rate is there because the
305 * rate set is checked when the station associates.
307 /* NB: the rate set is assumed sorted */
308 srate = ni->ni_rates.rs_nrates - 1;
309 for (; srate >= 0 && RATE(srate) != tp->ucastrate; srate--)
313 * The selected rate may not be available due to races
314 * and mode settings. Also orphaned nodes created in
315 * adhoc mode may not have any rate set so this lookup
316 * can fail. This is not fatal.
318 ath_rate_update(sc, ni, srate < 0 ? 0 : srate);
323 * Examine and potentially adjust the transmit rate.
326 ath_rate_ctl(void *arg, struct ieee80211_node *ni)
328 struct ath_softc *sc = arg;
329 struct onoe_node *on = ATH_NODE_ONOE(ATH_NODE(ni));
330 struct ieee80211_rateset *rs = &ni->ni_rates;
331 int dir = 0, nrate, enough;
335 * XXX: very primitive version.
337 enough = (on->on_tx_ok + on->on_tx_err >= 10);
339 /* no packet reached -> down */
340 if (on->on_tx_err > 0 && on->on_tx_ok == 0)
343 /* all packets needs retry in average -> down */
344 if (enough && on->on_tx_ok < on->on_tx_retr)
347 /* no error and less than rate_raise% of packets need retry -> up */
348 if (enough && on->on_tx_err == 0 &&
349 on->on_tx_retr < (on->on_tx_ok * ath_rate_raise) / 100)
352 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
353 "ok %d err %d retr %d upper %d dir %d",
354 on->on_tx_ok, on->on_tx_err, on->on_tx_retr, on->on_tx_upper, dir);
359 if (enough && on->on_tx_upper > 0)
365 sc->sc_stats.ast_rate_drop++;
370 /* raise rate if we hit rate_raise_threshold */
371 if (++on->on_tx_upper < ath_rate_raise_threshold)
374 if (nrate + 1 < rs->rs_nrates) {
376 sc->sc_stats.ast_rate_raise++;
381 if (nrate != on->on_rix) {
382 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
383 "%s: %dM -> %dM (%d ok, %d err, %d retr)", __func__,
385 (rs->rs_rates[nrate] & IEEE80211_RATE_VAL) / 2,
386 on->on_tx_ok, on->on_tx_err, on->on_tx_retr);
387 ath_rate_update(sc, ni, nrate);
389 on->on_tx_ok = on->on_tx_err = on->on_tx_retr = 0;
393 ath_rate_sysctlattach(struct ath_softc *sc)
395 struct sysctl_ctx_list *ctx = device_get_sysctl_ctx(sc->sc_dev);
396 struct sysctl_oid *tree = device_get_sysctl_tree(sc->sc_dev);
398 SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
399 "rate_interval", CTLFLAG_RW, &ath_rateinterval, 0,
400 "rate control: operation interval (ms)");
401 /* XXX bounds check values */
402 SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
403 "rate_raise", CTLFLAG_RW, &ath_rate_raise, 0,
404 "rate control: retry threshold to credit rate raise (%%)");
405 SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
406 "rate_raise_threshold", CTLFLAG_RW, &ath_rate_raise_threshold,0,
407 "rate control: # good periods before raising rate");
411 ath_rate_fetch_node_stats(struct ath_softc *sc, struct ath_node *an,
412 struct ath_rateioctl *re)
418 struct ath_ratectrl *
419 ath_rate_attach(struct ath_softc *sc)
421 struct onoe_softc *osc;
423 osc = malloc(sizeof(struct onoe_softc), M_DEVBUF, M_NOWAIT|M_ZERO);
426 osc->arc.arc_space = sizeof(struct onoe_node);
427 ath_rate_sysctlattach(sc);
433 ath_rate_detach(struct ath_ratectrl *arc)
435 struct onoe_softc *osc = (struct onoe_softc *) arc;