mac80211: improve minstrels rate sorting by means of throughput & probability

This patch improves the way minstrel sorts rates according to throughput and success probability. 3 FOR-loops across the entire rate set in function minstrel_update_stats() which where used to determine the fastest, second fastest and most robust rate are reduced to 1 FOR-loop. The sorted list of rates according throughput is extended to the best four rates as we need them in upcoming joint rate and power control. The sorting is done via the new function minstrel_sort_best_tp_rates(). The most robust rate selection is aligned with minstrel_ht's approach. Once any success probability is above 95% the one with the highest throughput is chosen as most robust rate. If success probabilities of all rates are below 95%, the rate with the highest succ. prob. is elected as most robust one

Thomas Huehn committed 13 years ago

Commit 2ff2b691 parent db8c5ee3 files · +49 −36Browse files

Unified · Split

3 files

net/mac80211/rc80211_minstrel.c +40 −31
net/mac80211/rc80211_minstrel.h +5 −3
net/mac80211/rc80211_minstrel_debugfs.c +4 −2

net/mac80211/rc80211_minstrel.c+40−31

@@ -69,14 +69,31 @@ rix_to_ndx(struct minstrel_sta_info *mi, int rix) · 68 unmodified lines
69	69	return i;
70	70	}
71	71
	72	+/* find & sort topmost throughput rates */
	73	+static inline void
	74	+minstrel_sort_best_tp_rates(struct minstrel_sta_info mi, int i, u8 tp_list)
	75	+{
	76	+ int j = MAX_THR_RATES;
	77	+
	78	+ while (j > 0 && mi->r[i].cur_tp > mi->r[tp_list[j - 1]].cur_tp)
	79	+ j--;
	80	+ if (j < MAX_THR_RATES - 1)
	81	+ memmove(&tp_list[j + 1], &tp_list[j], MAX_THR_RATES - (j + 1));
	82	+ if (j < MAX_THR_RATES)
	83	+ tp_list[j] = i;
	84	+}
	85	+
72	86	static void
73	87	minstrel_update_stats(struct minstrel_priv mp, struct minstrel_sta_info mi)
74	88	{
75		− u32 max_tp = 0, index_max_tp = 0, index_max_tp2 = 0;
76		− u32 max_prob = 0, index_max_prob = 0;
	89	+ u8 tmp_tp_rate[MAX_THR_RATES];
	90	+ u8 tmp_prob_rate = 0;
77	91	u32 usecs;
78	92	int i;
79	93
	94	+ for (i=0; i < MAX_THR_RATES; i++)
	95	+ tmp_tp_rate[i] = 0;
	96	+
80	97	for (i = 0; i < mi->n_rates; i++) {
81	98	struct minstrel_rate *mr = &mi->r[i];
82	99
@@ -120,35 +137,27 @@ minstrel_update_stats(struct minstrel_priv mp, struct minstrel_sta_info mi) · 37 unmodified lines
120	137	}
121	138	if (!mr->adjusted_retry_count)
122	139	mr->adjusted_retry_count = 2;
123		− }
124	140
125		− for (i = 0; i < mi->n_rates; i++) {
126		− struct minstrel_rate *mr = &mi->r[i];
127		− if (max_tp < mr->cur_tp) {
128		− index_max_tp = i;
129		− max_tp = mr->cur_tp;
130		− }
131		− if (max_prob < mr->probability) {
132		− index_max_prob = i;
133		− max_prob = mr->probability;
	141	+ minstrel_sort_best_tp_rates(mi, i, tmp_tp_rate);
	142	+
	143	+ /* To determine the most robust rate (max_prob_rate) used at
	144	+ * 3rd mmr stage we distinct between two cases:
	145	+ * (1) if any success probabilitiy >= 95%, out of those rates
	146	+ * choose the maximum throughput rate as max_prob_rate
	147	+ * (2) if all success probabilities < 95%, the rate with
	148	+ * highest success probability is choosen as max_prob_rate */
	149	+ if (mr->probability >= MINSTREL_FRAC(95,100)) {
	150	+ if (mr->cur_tp >= mi->r[tmp_prob_rate].cur_tp)
	151	+ tmp_prob_rate = i;
	152	+ } else {
	153	+ if (mr->probability >= mi->r[tmp_prob_rate].probability)
	154	+ tmp_prob_rate = i;
134	155	}
135	156	}
136	157
137		− max_tp = 0;
138		− for (i = 0; i < mi->n_rates; i++) {
139		− struct minstrel_rate *mr = &mi->r[i];
140		−
141		− if (i == index_max_tp)
142		− continue;
143		−
144		− if (max_tp < mr->cur_tp) {
145		− index_max_tp2 = i;
146		− max_tp = mr->cur_tp;
147		− }
148		− }
149		− mi->max_tp_rate = index_max_tp;
150		− mi->max_tp_rate2 = index_max_tp2;
151		− mi->max_prob_rate = index_max_prob;
	158	+ /* Assign the new rate set */
	159	+ memcpy(mi->max_tp_rate, tmp_tp_rate, sizeof(mi->max_tp_rate));
	160	+ mi->max_prob_rate = tmp_prob_rate;
152	161
153	162	/* Reset update timer */
154	163	mi->stats_update = jiffies;
@@ -254,7 +263,7 @@ minstrel_get_rate(void priv, struct ieee80211_sta sta, · 99 unmodified lines
254	263	sampling_ratio = mp->lookaround_rate;
255	264
256	265	/* init rateindex [ndx] with max throughput rate */
257		− ndx = mi->max_tp_rate;
	266	+ ndx = mi->max_tp_rate[0];
258	267
259	268	/* increase sum packet counter */
260	269	mi->packet_count++;
@@ -322,7 +331,7 @@ minstrel_get_rate(void priv, struct ieee80211_sta sta, · 61 unmodified lines
322	331	* to use it, as this only wastes precious airtime */
323	332	if (!mrr_capable && rate_sampling &&
324	333	(mi->r[ndx].probability > MINSTREL_FRAC(95, 100)))
325		− ndx = mi->max_tp_rate;
	334	+ ndx = mi->max_tp_rate[0];
326	335
327	336	/* mrr setup for 1st stage */
328	337	ar[0].idx = mi->r[ndx].rix;
@@ -342,9 +351,9 @@ minstrel_get_rate(void priv, struct ieee80211_sta sta, · 13 unmodified lines
342	351	if (indirect_rate_sampling)
343	352	mrr_ndx[0] = sample_ndx;
344	353	else
345		− mrr_ndx[0] = mi->max_tp_rate;
	354	+ mrr_ndx[0] = mi->max_tp_rate[0];
346	355	} else {
347		− mrr_ndx[0] = mi->max_tp_rate2;
	356	+ mrr_ndx[0] = mi->max_tp_rate[1];
348	357	}
349	358
350	359	/* mrr setup for 3rd & 4th stage */

net/mac80211/rc80211_minstrel.h+5−3

@@ -18,6 +18,9 @@ · 17 unmodified lines
18	18	#define MINSTREL_FRAC(val, div) (((val) << MINSTREL_SCALE) / div)
19	19	#define MINSTREL_TRUNC(val) ((val) >> MINSTREL_SCALE)
20	20
	21	+/* number of highest throughput rates to consider*/
	22	+#define MAX_THR_RATES 4
	23	+
21	24	/*
22	25	* Perform EWMA (Exponentially Weighted Moving Average) calculation
23	26	*/
@@ -65,9 +68,8 @@ struct minstrel_sta_info { · 41 unmodified lines
65	68
66	69	unsigned int lowest_rix;
67	70
68		− unsigned int max_tp_rate;
69		− unsigned int max_tp_rate2;
70		− unsigned int max_prob_rate;
	71	+ u8 max_tp_rate[MAX_THR_RATES];
	72	+ u8 max_prob_rate;
71	73	unsigned int packet_count;
72	74	unsigned int sample_count;
73	75	int sample_deferred;

net/mac80211/rc80211_minstrel_debugfs.c+4−2

@@ -73,8 +73,10 @@ minstrel_stats_open(struct inode inode, struct file file) · 72 unmodified lines
73	73	for (i = 0; i < mi->n_rates; i++) {
74	74	struct minstrel_rate *mr = &mi->r[i];
75	75
76		− *(p++) = (i == mi->max_tp_rate) ? 'T' : ' ';
77		− *(p++) = (i == mi->max_tp_rate2) ? 't' : ' ';
	76	+ *(p++) = (i == mi->max_tp_rate[0]) ? 'A' : ' ';
	77	+ *(p++) = (i == mi->max_tp_rate[1]) ? 'B' : ' ';
	78	+ *(p++) = (i == mi->max_tp_rate[2]) ? 'C' : ' ';
	79	+ *(p++) = (i == mi->max_tp_rate[3]) ? 'D' : ' ';
78	80	*(p++) = (i == mi->max_prob_rate) ? 'P' : ' ';
79	81	p += sprintf(p, "%3u%s", mr->bitrate / 2,
80	82	(mr->bitrate & 1 ? ".5" : " "));

mac80211: improve minstrels rate sorting by means of throughput & probability

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