/*
 * Update rate statistics and select new primary rates
 *
 * Rules for rate selection:
 *  - max_prob_rate must use only one stream, as a tradeoff between delivery
 *    probability and throughput during strong fluctuations
 *  - as long as the max prob rate has a probability of more than 3/4, pick
 *    higher throughput rates, even if the probablity is a bit lower
 */
static void
minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
{
	struct minstrel_mcs_group_data *mg;
	struct minstrel_rate_stats *mr;
	int cur_prob, cur_prob_tp, cur_tp, cur_tp2;
	int group, i, index;
	bool mi_rates_valid = false;

	if (mi->ampdu_packets > 0) {
		mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
			MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL);
		mi->ampdu_len = 0;
		mi->ampdu_packets = 0;
	}

	mi->sample_slow = 0;
	mi->sample_count = 0;

	for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
		bool mg_rates_valid = false;

		cur_prob = 0;
		cur_prob_tp = 0;
		cur_tp = 0;
		cur_tp2 = 0;

		mg = &mi->groups[group];
		if (!mg->supported)
			continue;

		mi->sample_count++;

		for (i = 0; i < MCS_GROUP_RATES; i++) {
			if (!(mg->supported & BIT(i)))
				continue;

			index = MCS_GROUP_RATES * group + i;

			/* initialize rates selections starting indexes */
			if (!mg_rates_valid) {
				mg->max_tp_rate = mg->max_tp_rate2 =
					mg->max_prob_rate = i;
				if (!mi_rates_valid) {
					mi->max_tp_rate = mi->max_tp_rate2 =
						mi->max_prob_rate = index;
					mi_rates_valid = true;
				}
				mg_rates_valid = true;
			}

			mr = &mg->rates[i];
			mr->retry_updated = false;
			minstrel_calc_rate_ewma(mr);
			minstrel_ht_calc_tp(mi, group, i);

			if (!mr->cur_tp)
				continue;

			if ((mr->cur_tp > cur_prob_tp && mr->probability >
			     MINSTREL_FRAC(3, 4)) || mr->probability > cur_prob) {
				mg->max_prob_rate = index;
				cur_prob = mr->probability;
				cur_prob_tp = mr->cur_tp;
			}

			if (mr->cur_tp > cur_tp) {
				swap(index, mg->max_tp_rate);
				cur_tp = mr->cur_tp;
				mr = minstrel_get_ratestats(mi, index);
			}

			if (index >= mg->max_tp_rate)
				continue;

			if (mr->cur_tp > cur_tp2) {
				mg->max_tp_rate2 = index;
				cur_tp2 = mr->cur_tp;
			}
		}
	}

	/* try to sample all available rates during each interval */
	mi->sample_count *= 8;

	cur_prob = 0;
	cur_prob_tp = 0;
	cur_tp = 0;
	cur_tp2 = 0;
	for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
		mg = &mi->groups[group];
		if (!mg->supported)
			continue;

		mr = minstrel_get_ratestats(mi, mg->max_tp_rate);
		if (cur_tp < mr->cur_tp) {
			mi->max_tp_rate2 = mi->max_tp_rate;
			cur_tp2 = cur_tp;
			mi->max_tp_rate = mg->max_tp_rate;
			cur_tp = mr->cur_tp;
			mi->max_prob_streams = minstrel_mcs_groups[group].streams - 1;
		}

		mr = minstrel_get_ratestats(mi, mg->max_tp_rate2);
		if (cur_tp2 < mr->cur_tp) {
			mi->max_tp_rate2 = mg->max_tp_rate2;
			cur_tp2 = mr->cur_tp;
		}
	}

	if (mi->max_prob_streams < 1)
		mi->max_prob_streams = 1;

	for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
		mg = &mi->groups[group];
		if (!mg->supported)
			continue;
		mr = minstrel_get_ratestats(mi, mg->max_prob_rate);
		if (cur_prob_tp < mr->cur_tp &&
		    minstrel_mcs_groups[group].streams <= mi->max_prob_streams) {
			mi->max_prob_rate = mg->max_prob_rate;
			cur_prob = mr->cur_prob;
			cur_prob_tp = mr->cur_tp;
		}
	}

#ifdef CPTCFG_MAC80211_DEBUGFS
	/* use fixed index if set */
	if (mp->fixed_rate_idx != -1) {
		mi->max_tp_rate = mp->fixed_rate_idx;
		mi->max_tp_rate2 = mp->fixed_rate_idx;
		mi->max_prob_rate = mp->fixed_rate_idx;
	}
#endif

	mi->stats_update = jiffies;
}
Esempio n. 2
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/*
 * Update rate statistics and select new primary rates
 *
 * Rules for rate selection:
 *  - max_prob_rate must use only one stream, as a tradeoff between delivery
 *    probability and throughput during strong fluctuations
 *  - as long as the max prob rate has a probability of more than 75%, pick
 *    higher throughput rates, even if the probablity is a bit lower
 */
static void
minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
{
	struct minstrel_mcs_group_data *mg;
	struct minstrel_rate_stats *mr;
	int group, i, j;
	u16 tmp_mcs_tp_rate[MAX_THR_RATES], tmp_group_tp_rate[MAX_THR_RATES];
	u16 tmp_cck_tp_rate[MAX_THR_RATES], index;

	if (mi->ampdu_packets > 0) {
		mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
			MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL);
		mi->ampdu_len = 0;
		mi->ampdu_packets = 0;
	}

	mi->sample_slow = 0;
	mi->sample_count = 0;

	/* Initialize global rate indexes */
	for(j = 0; j < MAX_THR_RATES; j++){
		tmp_mcs_tp_rate[j] = 0;
		tmp_cck_tp_rate[j] = 0;
	}

	/* Find best rate sets within all MCS groups*/
	for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {

		mg = &mi->groups[group];
		if (!mg->supported)
			continue;

		mi->sample_count++;

		/* (re)Initialize group rate indexes */
		for(j = 0; j < MAX_THR_RATES; j++)
			tmp_group_tp_rate[j] = group;

		for (i = 0; i < MCS_GROUP_RATES; i++) {
			if (!(mg->supported & BIT(i)))
				continue;

			index = MCS_GROUP_RATES * group + i;

			mr = &mg->rates[i];
			mr->retry_updated = false;
			minstrel_calc_rate_ewma(mr);
			minstrel_ht_calc_tp(mi, group, i);

			if (!mr->cur_tp)
				continue;

			/* Find max throughput rate set */
			if (group != MINSTREL_CCK_GROUP) {
				minstrel_ht_sort_best_tp_rates(mi, index,
							       tmp_mcs_tp_rate);
			} else if (group == MINSTREL_CCK_GROUP) {
				minstrel_ht_sort_best_tp_rates(mi, index,
							       tmp_cck_tp_rate);
			}

			/* Find max throughput rate set within a group */
			minstrel_ht_sort_best_tp_rates(mi, index,
						       tmp_group_tp_rate);

			/* Find max probability rate per group and global */
			minstrel_ht_set_best_prob_rate(mi, index);
		}

		memcpy(mg->max_group_tp_rate, tmp_group_tp_rate,
		       sizeof(mg->max_group_tp_rate));
	}

	/* Assign new rate set per sta */
	minstrel_ht_assign_best_tp_rates(mi, tmp_mcs_tp_rate, tmp_cck_tp_rate);
	memcpy(mi->max_tp_rate, tmp_mcs_tp_rate, sizeof(mi->max_tp_rate));

	/* Try to increase robustness of max_prob_rate*/
	minstrel_ht_prob_rate_reduce_streams(mi);

	/* try to sample all available rates during each interval */
	mi->sample_count *= 8;

#ifdef CONFIG_MAC80211_DEBUGFS
	/* use fixed index if set */
	if (mp->fixed_rate_idx != -1) {
		for (i = 0; i < 4; i++)
			mi->max_tp_rate[i] = mp->fixed_rate_idx;
		mi->max_prob_rate = mp->fixed_rate_idx;
	}
#endif

	/* Reset update timer */
	mi->stats_update = jiffies;
}