amrr.c

来自「Atheros wifi driver source code」· C语言 代码 · 共 592 行 · 第 1/2 页

		 * the node.  We know the rate is there because the
		 * rate set is checked when the station associates.
		 */
		const struct ieee80211_rateset *rs =
			&ic->ic_sup_rates[ic->ic_curmode];
		int r = rs->rs_rates[ic->ic_fixed_rate] & IEEE80211_RATE_VAL;
		/* NB: the rate set is assumed sorted */
		srate = ni->ni_rates.rs_nrates - 1;
		for (; srate >= 0 && RATE(srate) != r; srate--)
			;
		KASSERT(srate >= 0,
			("fixed rate %d not in rate set", ic->ic_fixed_rate));
	}
	ath_rate_update(sc, ni, srate);
#undef RATE
}

static void
ath_rate_cb(void *arg, struct ieee80211_node *ni)
{
	ath_rate_update(ni->ni_ic->ic_ifp->if_softc, ni, (int)(uintptr_t) arg);
}

/*
 * Reset the rate control state for each 802.11 state transition.
 */
void
ath_rate_newstate(struct ath_softc *sc, enum ieee80211_state state)
{
	struct amrr_softc *asc = (struct amrr_softc *) sc->sc_rc;
	struct ieee80211com *ic = &sc->sc_ic;
	struct ieee80211_node *ni;

	if (state == IEEE80211_S_INIT) {
		del_timer(&asc->timer);
		return;
	}
	if (ic->ic_opmode == IEEE80211_M_STA) {
		/*
		 * Reset local xmit state; this is really only
		 * meaningful when operating in station mode.
		 */
		ni = ic->ic_bss;
		if (state == IEEE80211_S_RUN) {
			ath_rate_ctl_start(sc, ni);
		} else {
			ath_rate_update(sc, ni, 0);
		}
	} else {
		/*
		 * When operating as a station the node table holds
		 * the AP's that were discovered during scanning.
		 * For any other operating mode we want to reset the
		 * tx rate state of each node.
		 */
		ieee80211_iterate_nodes(&ic->ic_sta, ath_rate_cb, 0);
		ath_rate_update(sc, ic->ic_bss, 0);
	}
	if (ic->ic_fixed_rate == -1 && state == IEEE80211_S_RUN) {
		int interval;
		/*
		 * Start the background rate control thread if we
		 * are not configured to use a fixed xmit rate.
		 */
		interval = ath_rateinterval;
		if (ic->ic_opmode == IEEE80211_M_STA)
			interval /= 2;
		mod_timer(&asc->timer, jiffies + ((HZ * interval) / 1000));
	}
}
EXPORT_SYMBOL(ath_rate_newstate);

/* 
 * Examine and potentially adjust the transmit rate.
 */
static void
ath_rate_ctl(void *arg, struct ieee80211_node *ni)
{
	struct ath_softc *sc = arg;
	struct amrr_node *amn = ATH_NODE_AMRR(ATH_NODE (ni));
	int old_rate;

#define is_success(amn) \
(amn->amn_tx_try1_cnt  < (amn->amn_tx_try0_cnt/10))
#define is_enough(amn) \
(amn->amn_tx_try0_cnt > 10)
#define is_failure(amn) \
(amn->amn_tx_try1_cnt > (amn->amn_tx_try0_cnt/3))
#define is_max_rate(ni) \
((ni->ni_txrate + 1) >= ni->ni_rates.rs_nrates)
#define is_min_rate(ni) \
(ni->ni_txrate == 0)

	old_rate = ni->ni_txrate;
  
  	DPRINTF (sc, "cnt0: %d cnt1: %d cnt2: %d cnt3: %d -- threshold: %d\n",
		 amn->amn_tx_try0_cnt,
		 amn->amn_tx_try1_cnt,
		 amn->amn_tx_try2_cnt,
		 amn->amn_tx_try3_cnt,
		 amn->amn_success_threshold);
  	if (is_success (amn) && is_enough (amn)) {
		amn->amn_success++;
		if (amn->amn_success == amn->amn_success_threshold &&
  		    !is_max_rate (ni)) {
  			amn->amn_recovery = 1;
  			amn->amn_success = 0;
  			ni->ni_txrate++;
			DPRINTF (sc, "increase rate to %d\n", ni->ni_txrate);
  		} else {
			amn->amn_recovery = 0;
		}
  	} else if (is_failure (amn)) {
  		amn->amn_success = 0;
  		if (!is_min_rate (ni)) {
  			if (amn->amn_recovery) {
  				/* recovery failure. */
  				amn->amn_success_threshold *= 2;
  				amn->amn_success_threshold = min (amn->amn_success_threshold,
								  (u_int)ath_rate_max_success_threshold);
 				DPRINTF (sc, "decrease rate recovery thr: %d\n", amn->amn_success_threshold);
  			} else {
  				/* simple failure. */
 				amn->amn_success_threshold = ath_rate_min_success_threshold;
 				DPRINTF (sc, "decrease rate normal thr: %d\n", amn->amn_success_threshold);
  			}
			amn->amn_recovery = 0;
  			ni->ni_txrate--;
   		} else {
			amn->amn_recovery = 0;
		}

   	}
	if (is_enough (amn) || old_rate != ni->ni_txrate) {
		/* reset counters. */
		amn->amn_tx_try0_cnt = 0;
		amn->amn_tx_try1_cnt = 0;
		amn->amn_tx_try2_cnt = 0;
		amn->amn_tx_try3_cnt = 0;
		amn->amn_tx_failure_cnt = 0;
	}
	if (old_rate != ni->ni_txrate) {
		ath_rate_update(sc, ni, ni->ni_txrate);
	}
}

static void
ath_ratectl(unsigned long data)
{
	struct net_device *dev = (struct net_device *)data;
	struct ath_softc *sc = dev->priv;
	struct amrr_softc *asc = (struct amrr_softc *) sc->sc_rc;
	struct ieee80211com *ic = &sc->sc_ic;
	int interval;

	if (dev->flags & IFF_RUNNING) {
		sc->sc_stats.ast_rate_calls++;

		if (ic->ic_opmode == IEEE80211_M_STA)
			ath_rate_ctl(sc, ic->ic_bss);	/* NB: no reference */
		else
			ieee80211_iterate_nodes(&ic->ic_sta, ath_rate_ctl, sc);
	}
	interval = ath_rateinterval;
	if (ic->ic_opmode == IEEE80211_M_STA)
		interval /= 2;
	asc->timer.expires = jiffies + ((HZ * interval) / 1000);
	add_timer(&asc->timer);
}

struct ath_ratectrl *
ath_rate_attach(struct ath_softc *sc)
{
	struct amrr_softc *asc;

	asc = kmalloc(sizeof(struct amrr_softc), GFP_ATOMIC);
	if (asc == NULL)
		return NULL;
	asc->arc.arc_space = sizeof(struct amrr_node);
	init_timer(&asc->timer);
	asc->timer.data = (unsigned long) &sc->sc_dev;
	asc->timer.function = ath_ratectl;

	return &asc->arc;
}
EXPORT_SYMBOL(ath_rate_attach);

void
ath_rate_detach(struct ath_ratectrl *arc)
{
	struct amrr_softc *asc = (struct amrr_softc *) arc;

	del_timer(&asc->timer);
	kfree(asc);
}
EXPORT_SYMBOL(ath_rate_detach);

static	int minrateinterval = 500;		/* 500ms */
static	int maxint = 0x7fffffff;		/* 32-bit big */
static  int min_threshold = 1;

#define	CTL_AUTO	-2	/* cannot be CTL_ANY or CTL_NONE */

/*
 * Static (i.e. global) sysctls.
 */
enum {
	DEV_ATH		= 9,			/* XXX known by many */
};

static ctl_table ath_rate_static_sysctls[] = {
	{ .ctl_name	= CTL_AUTO,
	  .procname	= "interval",
	  .mode		= 0644,
	  .data		= &ath_rateinterval,
	  .maxlen	= sizeof(ath_rateinterval),
	  .extra1	= &minrateinterval,
	  .extra2	= &maxint,
	  .proc_handler	= proc_dointvec_minmax
	},
	{ .ctl_name	= CTL_AUTO,
	  .procname	= "max_success_threshold",
	  .mode		= 0644,
	  .data		= &ath_rate_max_success_threshold,
	  .maxlen	= sizeof(ath_rate_max_success_threshold),
	  .extra1	= &min_threshold,
	  .extra2	= &maxint,
	  .proc_handler	= proc_dointvec_minmax
	},
	{ .ctl_name	= CTL_AUTO,
	  .procname	= "min_success_threshold",
	  .mode		= 0644,
	  .data		= &ath_rate_min_success_threshold,
	  .maxlen	= sizeof(ath_rate_min_success_threshold),
	  .extra1	= &min_threshold,
	  .extra2	= &maxint,
	  .proc_handler	= proc_dointvec_minmax
	},
	{ 0 }
};
static ctl_table ath_rate_table[] = {
	{ .ctl_name	= CTL_AUTO,
	  .procname	= "rate",
	  .mode		= 0555,
	  .child	= ath_rate_static_sysctls
	}, { 0 }
};
static ctl_table ath_ath_table[] = {
	{ .ctl_name	= DEV_ATH,
	  .procname	= "ath",
	  .mode		= 0555,
	  .child	= ath_rate_table
	}, { 0 }
};
static ctl_table ath_root_table[] = {
	{ .ctl_name	= CTL_DEV,
	  .procname	= "dev",
	  .mode		= 0555,
	  .child	= ath_ath_table
	}, { 0 }
};
static struct ctl_table_header *ath_sysctl_header;

MODULE_AUTHOR("INRIA, Mathieu Lacage");
MODULE_DESCRIPTION("AMRR Rate control algorithm");
#ifdef MODULE_LICENSE
MODULE_LICENSE("Dual BSD/GPL");
#endif

static char *version = "0.1";
static char *dev_info = "ath_rate_amrr";

static int __init
init_ath_rate_amrr(void)
{
	printk(KERN_INFO "%s: %s\n", dev_info, version);

#ifdef CONFIG_SYSCTL
	ath_sysctl_header = register_sysctl_table(ath_root_table, 1);
#endif
	return (0);
}
module_init(init_ath_rate_amrr);

static void __exit
exit_ath_rate_amrr(void)
{
#ifdef CONFIG_SYSCTL
	if (ath_sysctl_header != NULL)
		unregister_sysctl_table(ath_sysctl_header);
#endif

	printk(KERN_INFO "%s: unloaded\n", dev_info);
}
module_exit(exit_ath_rate_amrr);