| 1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677 |
- From: Felix Fietkau <nbd@openwrt.org>
- Date: Thu, 3 Mar 2016 23:20:06 +0100
- Subject: [PATCH] mac80211: minstrel_ht: improve sample rate skip logic
- There were a few issues that were slowing down the process of finding
- the optimal rate, especially on devices with multi-rate retry
- limitations:
- When max_tp_rate[0] was slower than max_tp_rate[1], the code did not
- sample max_tp_rate[1], which would often allow it to switch places with
- max_tp_rate[0] (e.g. if only the first sampling attempts were bad, but the
- rate is otherwise good).
- Also, sample attempts of rates between max_tp_rate[0] and [1] were being
- ignored in this case, because the code only checked if the rate was
- slower than [1].
- Fix this by checking against the fastest / second fastest max_tp_rate
- instead of assuming a specific order between the two.
- In my tests this patch significantly reduces the time until minstrel_ht
- finds the optimal rate right after assoc
- Signed-off-by: Felix Fietkau <nbd@openwrt.org>
- ---
- --- a/net/mac80211/rc80211_minstrel_ht.c
- +++ b/net/mac80211/rc80211_minstrel_ht.c
- @@ -958,6 +958,7 @@ minstrel_get_sample_rate(struct minstrel
- 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) {
- @@ -979,14 +980,22 @@ minstrel_get_sample_rate(struct minstrel
- 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 currently
- - * used rates.
- + * 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_tp_rate[1] ||
- - sample_idx == mi->max_prob_rate)
- + if (sample_idx == mi->max_tp_rate[0] || sample_idx == mi->max_prob_rate)
- return -1;
-
- /*
- @@ -1001,10 +1010,10 @@ minstrel_get_sample_rate(struct minstrel
- * if the link is working perfectly.
- */
-
- - cur_max_tp_streams = minstrel_mcs_groups[mi->max_tp_rate[0] /
- + cur_max_tp_streams = minstrel_mcs_groups[tp_rate1 /
- MCS_GROUP_RATES].streams;
- sample_dur = minstrel_get_duration(sample_idx);
- - if (sample_dur >= minstrel_get_duration(mi->max_tp_rate[1]) &&
- + 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))) {
|
