static int
minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
{
struct minstrel_rate_stats *mr;
struct minstrel_mcs_group_data *mg;
unsigned int sample_dur, sample_group;
int sample_idx = 0;
if (mi->sample_wait > 0) {
mi->sample_wait--;
return -1;
}
if (!mi->sample_tries)
return -1;
mg = &mi->groups[mi->sample_group];
sample_idx = sample_table[mg->column][mg->index];
mr = &mg->rates[sample_idx];
sample_group = mi->sample_group;
sample_idx += sample_group * MCS_GROUP_RATES;
minstrel_next_sample_idx(mi);
/*
* Sampling might add some overhead (RTS, no aggregation)
* to the frame. Hence, don't use sampling for the currently
* used rates.
*/
if (sample_idx == mi->max_tp_rate ||
sample_idx == mi->max_tp_rate2 ||
sample_idx == mi->max_prob_rate)
return -1;
/*
* Do not sample if the probability is already higher than 95%
* to avoid wasting airtime.
*/
if (mr->probability > MINSTREL_FRAC(95, 100))
return -1;
/*
* Make sure that lower rates get sampled only occasionally,
* if the link is working perfectly.
*/
sample_dur = minstrel_get_duration(sample_idx);
if (sample_dur >= minstrel_get_duration(mi->max_tp_rate2) &&
(mi->max_prob_streams <
minstrel_mcs_groups[sample_group].streams ||
sample_dur >= minstrel_get_duration(mi->max_prob_rate))) {
if (mr->sample_skipped < 20)
return -1;
if (mi->sample_slow++ > 2)
return -1;
}
mi->sample_tries--;
return sample_idx;
}
static void
minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
int index)
{
struct minstrel_rate_stats *mrs;
unsigned int tx_time, tx_time_rtscts, tx_time_data;
unsigned int cw = mp->cw_min;
unsigned int ctime = 0;
unsigned int t_slot = 9; /* FIXME */
unsigned int ampdu_len = minstrel_ht_avg_ampdu_len(mi);
unsigned int overhead = 0, overhead_rtscts = 0;
mrs = minstrel_get_ratestats(mi, index);
if (mrs->prob_ewma < MINSTREL_FRAC(1, 10)) {
mrs->retry_count = 1;
mrs->retry_count_rtscts = 1;
return;
}
mrs->retry_count = 2;
mrs->retry_count_rtscts = 2;
mrs->retry_updated = true;
tx_time_data = minstrel_get_duration(index) * ampdu_len / 1000;
/* Contention time for first 2 tries */
ctime = (t_slot * cw) >> 1;
cw = min((cw << 1) | 1, mp->cw_max);
ctime += (t_slot * cw) >> 1;
cw = min((cw << 1) | 1, mp->cw_max);
if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) {
overhead = mi->overhead;
overhead_rtscts = mi->overhead_rtscts;
}
/* Total TX time for data and Contention after first 2 tries */
tx_time = ctime + 2 * (overhead + tx_time_data);
tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data);
/* See how many more tries we can fit inside segment size */
do {
/* Contention time for this try */
ctime = (t_slot * cw) >> 1;
cw = min((cw << 1) | 1, mp->cw_max);
/* Total TX time after this try */
tx_time += ctime + overhead + tx_time_data;
tx_time_rtscts += ctime + overhead_rtscts + tx_time_data;
if (tx_time_rtscts < mp->segment_size)
mrs->retry_count_rtscts++;
} while ((tx_time < mp->segment_size) &&
(++mrs->retry_count < mp->max_retry));
}
static int
minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
{
struct minstrel_rate_stats *mrs;
struct minstrel_mcs_group_data *mg;
unsigned int sample_dur, sample_group, cur_max_tp_streams;
int tp_rate1, tp_rate2;
int sample_idx = 0;
if (mi->sample_wait > 0) {
mi->sample_wait--;
return -1;
}
if (!mi->sample_tries)
return -1;
sample_group = mi->sample_group;
mg = &mi->groups[sample_group];
sample_idx = sample_table[mg->column][mg->index];
minstrel_set_next_sample_idx(mi);
if (!(mi->supported[sample_group] & BIT(sample_idx)))
return -1;
mrs = &mg->rates[sample_idx];
sample_idx += sample_group * MCS_GROUP_RATES;
/* Set tp_rate1, tp_rate2 to the highest / second highest max_tp_rate */
if (minstrel_get_duration(mi->max_tp_rate[0]) >
minstrel_get_duration(mi->max_tp_rate[1])) {
tp_rate1 = mi->max_tp_rate[1];
tp_rate2 = mi->max_tp_rate[0];
} else {
tp_rate1 = mi->max_tp_rate[0];
tp_rate2 = mi->max_tp_rate[1];
}
/*
* Sampling might add some overhead (RTS, no aggregation)
* to the frame. Hence, don't use sampling for the highest currently
* used highest throughput or probability rate.
*/
if (sample_idx == mi->max_tp_rate[0] || sample_idx == mi->max_prob_rate)
return -1;
/*
* Do not sample if the probability is already higher than 95%,
* or if the rate is 3 times slower than the current max probability
* rate, to avoid wasting airtime.
*/
sample_dur = minstrel_get_duration(sample_idx);
if (mrs->prob_ewma > MINSTREL_FRAC(95, 100) ||
minstrel_get_duration(mi->max_prob_rate) * 3 < sample_dur)
return -1;
/*
* Make sure that lower rates get sampled only occasionally,
* if the link is working perfectly.
*/
cur_max_tp_streams = minstrel_mcs_groups[tp_rate1 /
MCS_GROUP_RATES].streams;
if (sample_dur >= minstrel_get_duration(tp_rate2) &&
(cur_max_tp_streams - 1 <
minstrel_mcs_groups[sample_group].streams ||
sample_dur >= minstrel_get_duration(mi->max_prob_rate))) {
if (mrs->sample_skipped < 20)
return -1;
if (mi->sample_slow++ > 2)
return -1;
}
mi->sample_tries--;
return sample_idx;
}
