1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
4  * Copyright (c) 2002-2007 Sam Leffler, Errno Consulting
34  * Atsushi Onoe's rate control algorithm.
73  * Default parameters for the rate control algorithm.  These are
74  * all tunable with sysctls.  The rate controller runs periodically
78  * it gives a "raise rate credit".  If transmits look to not be working
80  * the transmit rate is raised.  Various error conditions force the
81  * the transmit rate to be dropped.
87  * the transmit rate is increased.
91 static	int ath_rateinterval = 1000;		/* rate ctl interval (ms)  */
93 static	int ath_rate_raise_threshold = 10;	/* rate ctl raise threshold */
96 			int rate);
119 	*rix = on->on_tx_rix0;  in ath_rate_findrate()
120 	*try0 = on->on_tx_try0;  in ath_rate_findrate()
122 		*txrate = on->on_tx_rate0sp;  in ath_rate_findrate()
124 		*txrate = on->on_tx_rate0;  in ath_rate_findrate()
125 	*maxdur = -1;  in ath_rate_findrate()
126 	*maxpktlen = -1;  in ath_rate_findrate()
133  * the returned rate with the relevant preamble rate flag.
143 	rc[0].rix = on->on_tx_rate0;  in ath_rate_getxtxrates()
144 	rc[1].rix = on->on_tx_rate1;  in ath_rate_getxtxrates()
145 	rc[2].rix = on->on_tx_rate2;  in ath_rate_getxtxrates()
146 	rc[3].rix = on->on_tx_rate3;  in ath_rate_getxtxrates()
148 	rc[0].tries = on->on_tx_try0;  in ath_rate_getxtxrates()
160 	ath_hal_setupxtxdesc(sc->sc_ah, ds  in ath_rate_setupxtxdesc()
161 		, on->on_tx_rate1sp, 2	/* series 1 */  in ath_rate_setupxtxdesc()
162 		, on->on_tx_rate2sp, 2	/* series 2 */  in ath_rate_setupxtxdesc()
163 		, on->on_tx_rate3sp, 2	/* series 3 */  in ath_rate_setupxtxdesc()
174 	if (ts->ts_status == 0)  in ath_rate_tx_complete()
175 		on->on_tx_ok++;  in ath_rate_tx_complete()
177 		on->on_tx_err++;  in ath_rate_tx_complete()
178 	on->on_tx_retr += ts->ts_shortretry  in ath_rate_tx_complete()
179 			+ ts->ts_longretry;  in ath_rate_tx_complete()
180 	if (on->on_interval != 0 && ticks - on->on_ticks > on->on_interval) {  in ath_rate_tx_complete()
181 		ath_rate_ctl(sc, &an->an_node);  in ath_rate_tx_complete()
182 		on->on_ticks = ticks;  in ath_rate_tx_complete()
190 		ath_rate_ctl_start(sc, &an->an_node);  in ath_rate_newassoc()
199 ath_rate_update(struct ath_softc *sc, struct ieee80211_node *ni, int rate)  in ath_rate_update()  argument
203 	struct ieee80211vap *vap = ni->ni_vap;  in ath_rate_update()
204 	const HAL_RATE_TABLE *rt = sc->sc_currates;  in ath_rate_update()
208 	KASSERT(rt != NULL, ("no rate table, mode %u", sc->sc_curmode));  in ath_rate_update()
211 	     "%s: set xmit rate to %dM", __func__,  in ath_rate_update()
212 	     ni->ni_rates.rs_nrates > 0 ?  in ath_rate_update()
213 		(ni->ni_rates.rs_rates[rate] & IEEE80211_RATE_VAL) / 2 : 0);  in ath_rate_update()
216 	 * Before associating a node has no rate set setup  in ath_rate_update()
220 	 * lowest hardware rate.  in ath_rate_update()
222 	if (ni->ni_rates.rs_nrates == 0)  in ath_rate_update()
224 	on->on_rix = rate;  in ath_rate_update()
225 	dot11rate = ni->ni_rates.rs_rates[rate] & IEEE80211_RATE_VAL;  in ath_rate_update()
227 	on->on_tx_rix0 = sc->sc_rixmap[dot11rate];  in ath_rate_update()
228 	on->on_tx_rate0 = rt->info[on->on_tx_rix0].rateCode;  in ath_rate_update()
230 	on->on_tx_rate0sp = on->on_tx_rate0 |  in ath_rate_update()
231 		rt->info[on->on_tx_rix0].shortPreamble;  in ath_rate_update()
232 	if (sc->sc_mrretry) {  in ath_rate_update()
234 		 * Hardware supports multi-rate retry; setup two  in ath_rate_update()
235 		 * step-down retry rates and make the lowest rate  in ath_rate_update()
240 		on->on_tx_try0 = 1 + 3;		/* 4 tries at rate 0 */  in ath_rate_update()
241 		if (--rate >= 0) {  in ath_rate_update()
242 			rix = sc->sc_rixmap[  in ath_rate_update()
243 				ni->ni_rates.rs_rates[rate]&IEEE80211_RATE_VAL];  in ath_rate_update()
244 			on->on_tx_rate1 = rt->info[rix].rateCode;  in ath_rate_update()
245 			on->on_tx_rate1sp = on->on_tx_rate1 |  in ath_rate_update()
246 				rt->info[rix].shortPreamble;  in ath_rate_update()
248 			on->on_tx_rate1 = on->on_tx_rate1sp = 0;  in ath_rate_update()
250 		if (--rate >= 0) {  in ath_rate_update()
251 			rix = sc->sc_rixmap[  in ath_rate_update()
252 				ni->ni_rates.rs_rates[rate]&IEEE80211_RATE_VAL];  in ath_rate_update()
253 			on->on_tx_rate2 = rt->info[rix].rateCode;  in ath_rate_update()
254 			on->on_tx_rate2sp = on->on_tx_rate2 |  in ath_rate_update()
255 				rt->info[rix].shortPreamble;  in ath_rate_update()
257 			on->on_tx_rate2 = on->on_tx_rate2sp = 0;  in ath_rate_update()
259 		if (rate > 0) {  in ath_rate_update()
261 			on->on_tx_rate3 = rt->info[0].rateCode;  in ath_rate_update()
262 			on->on_tx_rate3sp =  in ath_rate_update()
263 				on->on_tx_rate3 | rt->info[0].shortPreamble;  in ath_rate_update()
265 			on->on_tx_rate3 = on->on_tx_rate3sp = 0;  in ath_rate_update()
268 		on->on_tx_try0 = ATH_TXMAXTRY;	/* max tries at rate 0 */  in ath_rate_update()
269 		on->on_tx_rate1 = on->on_tx_rate1sp = 0;  in ath_rate_update()
270 		on->on_tx_rate2 = on->on_tx_rate2sp = 0;  in ath_rate_update()
271 		on->on_tx_rate3 = on->on_tx_rate3sp = 0;  in ath_rate_update()
274 	on->on_tx_ok = on->on_tx_err = on->on_tx_retr = on->on_tx_upper = 0;  in ath_rate_update()
276 	on->on_interval = ath_rateinterval;  in ath_rate_update()
277 	if (vap->iv_opmode == IEEE80211_M_STA)  in ath_rate_update()
278 		on->on_interval /= 2;  in ath_rate_update()
279 	on->on_interval = (on->on_interval * hz) / 1000;  in ath_rate_update()
283  * Set the starting transmit rate for a node.
288 #define	RATE(_ix)	(ni->ni_rates.rs_rates[(_ix)] & IEEE80211_RATE_VAL)  in ath_rate_ctl_start()  macro
289 	const struct ieee80211_txparam *tp = ni->ni_txparms;  in ath_rate_ctl_start()
292 	KASSERT(ni->ni_rates.rs_nrates > 0, ("no rates"));  in ath_rate_ctl_start()
293 	if (tp == NULL || tp->ucastrate == IEEE80211_FIXED_RATE_NONE) {  in ath_rate_ctl_start()
295 		 * No fixed rate is requested. For 11b start with  in ath_rate_ctl_start()
296 		 * the highest negotiated rate; otherwise, for 11g  in ath_rate_ctl_start()
299 		srate = ni->ni_rates.rs_nrates - 1;  in ath_rate_ctl_start()
300 		if (sc->sc_curmode != IEEE80211_MODE_11B) {  in ath_rate_ctl_start()
302 			 * Scan the negotiated rate set to find the  in ath_rate_ctl_start()
303 			 * closest rate.  in ath_rate_ctl_start()
305 			/* NB: the rate set is assumed sorted */  in ath_rate_ctl_start()
306 			for (; srate >= 0 && RATE(srate) > 72; srate--)  in ath_rate_ctl_start()
311 		 * A fixed rate is to be used; ic_fixed_rate is the  in ath_rate_ctl_start()
312 		 * IEEE code for this rate (sans basic bit).  Convert this  in ath_rate_ctl_start()
313 		 * to the index into the negotiated rate set for  in ath_rate_ctl_start()
314 		 * the node.  We know the rate is there because the  in ath_rate_ctl_start()
315 		 * rate set is checked when the station associates.  in ath_rate_ctl_start()
317 		/* NB: the rate set is assumed sorted */  in ath_rate_ctl_start()
318 		srate = ni->ni_rates.rs_nrates - 1;  in ath_rate_ctl_start()
319 		for (; srate >= 0 && RATE(srate) != tp->ucastrate; srate--)  in ath_rate_ctl_start()
323 	 * The selected rate may not be available due to races  in ath_rate_ctl_start()
325 	 * adhoc mode may not have any rate set so this lookup  in ath_rate_ctl_start()
329 #undef RATE  in ath_rate_ctl_start()
333  * Examine and potentially adjust the transmit rate.
340 	struct ieee80211_rateset *rs = &ni->ni_rates;  in ath_rate_ctl()
344 	 * Rate control  in ath_rate_ctl()
347 	enough = (on->on_tx_ok + on->on_tx_err >= 10);  in ath_rate_ctl()
349 	/* no packet reached -> down */  in ath_rate_ctl()
350 	if (on->on_tx_err > 0 && on->on_tx_ok == 0)  in ath_rate_ctl()
351 		dir = -1;  in ath_rate_ctl()
353 	/* all packets needs retry in average -> down */  in ath_rate_ctl()
354 	if (enough && on->on_tx_ok < on->on_tx_retr)  in ath_rate_ctl()
355 		dir = -1;  in ath_rate_ctl()
357 	/* no error and less than rate_raise% of packets need retry -> up */  in ath_rate_ctl()
358 	if (enough && on->on_tx_err == 0 &&  in ath_rate_ctl()
359 	    on->on_tx_retr < (on->on_tx_ok * ath_rate_raise) / 100)  in ath_rate_ctl()
362 	IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,  in ath_rate_ctl()
364 	    on->on_tx_ok, on->on_tx_err, on->on_tx_retr, on->on_tx_upper, dir);  in ath_rate_ctl()
366 	nrate = on->on_rix;  in ath_rate_ctl()
369 		if (enough && on->on_tx_upper > 0)  in ath_rate_ctl()
370 			on->on_tx_upper--;  in ath_rate_ctl()
372 	case -1:  in ath_rate_ctl()
374 			nrate--;  in ath_rate_ctl()
375 			sc->sc_stats.ast_rate_drop++;  in ath_rate_ctl()
377 		on->on_tx_upper = 0;  in ath_rate_ctl()
380 		/* raise rate if we hit rate_raise_threshold */  in ath_rate_ctl()
381 		if (++on->on_tx_upper < ath_rate_raise_threshold)  in ath_rate_ctl()
383 		on->on_tx_upper = 0;  in ath_rate_ctl()
384 		if (nrate + 1 < rs->rs_nrates) {  in ath_rate_ctl()
386 			sc->sc_stats.ast_rate_raise++;  in ath_rate_ctl()
391 	if (nrate != on->on_rix) {  in ath_rate_ctl()
392 		IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,  in ath_rate_ctl()
393 		    "%s: %dM -> %dM (%d ok, %d err, %d retr)", __func__,  in ath_rate_ctl()
395 		    (rs->rs_rates[nrate] & IEEE80211_RATE_VAL) / 2,  in ath_rate_ctl()
396 		    on->on_tx_ok, on->on_tx_err, on->on_tx_retr);  in ath_rate_ctl()
399 		on->on_tx_ok = on->on_tx_err = on->on_tx_retr = 0;  in ath_rate_ctl()
405 	struct sysctl_ctx_list *ctx = device_get_sysctl_ctx(sc->sc_dev);  in ath_rate_sysctlattach()
406 	struct sysctl_oid *tree = device_get_sysctl_tree(sc->sc_dev);  in ath_rate_sysctlattach()
410 		"rate control: operation interval (ms)");  in ath_rate_sysctlattach()
414 		"rate control: retry threshold to credit rate raise (%%)");  in ath_rate_sysctlattach()
417 		"rate control: # good periods before raising rate");  in ath_rate_sysctlattach()
436 	osc->arc.arc_space = sizeof(struct onoe_node);  in ath_rate_attach()
439 	return &osc->arc;  in ath_rate_attach()