OpenWrt – Rev 1
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From: Felix Fietkau <nbd@nbd.name>
Date: Sat, 10 Feb 2018 12:45:47 +0100
Subject: [PATCH] mac80211: minstrel: reduce minstrel_mcs_groups size
By storing a shift value for all duration values of a group, we can
reduce precision by a neglegible amount to make it fit into a u16 value.
This improves cache footprint and reduces size:
Before:
text data bss dec hex filename
10024 116 0 10140 279c rc80211_minstrel_ht.o
After:
text data bss dec hex filename
9368 116 0 9484 250c rc80211_minstrel_ht.o
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -52,22 +52,23 @@
_streams - 1
/* MCS rate information for an MCS group */
-#define MCS_GROUP(_streams, _sgi, _ht40) \
+#define MCS_GROUP(_streams, _sgi, _ht40, _s) \
[GROUP_IDX(_streams, _sgi, _ht40)] = { \
.streams = _streams, \
+ .shift = _s, \
.flags = \
IEEE80211_TX_RC_MCS | \
(_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) | \
(_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0), \
.duration = { \
- MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26), \
- MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52), \
- MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78), \
- MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104), \
- MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156), \
- MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208), \
- MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234), \
- MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260) \
+ MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26) >> _s, \
+ MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52) >> _s, \
+ MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78) >> _s, \
+ MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104) >> _s, \
+ MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156) >> _s, \
+ MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208) >> _s, \
+ MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234) >> _s, \
+ MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260) >> _s \
} \
}
@@ -80,9 +81,10 @@
#define BW2VBPS(_bw, r3, r2, r1) \
(_bw == BW_80 ? r3 : _bw == BW_40 ? r2 : r1)
-#define VHT_GROUP(_streams, _sgi, _bw) \
+#define VHT_GROUP(_streams, _sgi, _bw, _s) \
[VHT_GROUP_IDX(_streams, _sgi, _bw)] = { \
.streams = _streams, \
+ .shift = _s, \
.flags = \
IEEE80211_TX_RC_VHT_MCS | \
(_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) | \
@@ -90,25 +92,25 @@
_bw == BW_40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0), \
.duration = { \
MCS_DURATION(_streams, _sgi, \
- BW2VBPS(_bw, 117, 54, 26)), \
+ BW2VBPS(_bw, 117, 54, 26)) >> _s, \
MCS_DURATION(_streams, _sgi, \
- BW2VBPS(_bw, 234, 108, 52)), \
+ BW2VBPS(_bw, 234, 108, 52)) >> _s, \
MCS_DURATION(_streams, _sgi, \
- BW2VBPS(_bw, 351, 162, 78)), \
+ BW2VBPS(_bw, 351, 162, 78)) >> _s, \
MCS_DURATION(_streams, _sgi, \
- BW2VBPS(_bw, 468, 216, 104)), \
+ BW2VBPS(_bw, 468, 216, 104)) >> _s, \
MCS_DURATION(_streams, _sgi, \
- BW2VBPS(_bw, 702, 324, 156)), \
+ BW2VBPS(_bw, 702, 324, 156)) >> _s, \
MCS_DURATION(_streams, _sgi, \
- BW2VBPS(_bw, 936, 432, 208)), \
+ BW2VBPS(_bw, 936, 432, 208)) >> _s, \
MCS_DURATION(_streams, _sgi, \
- BW2VBPS(_bw, 1053, 486, 234)), \
+ BW2VBPS(_bw, 1053, 486, 234)) >> _s, \
MCS_DURATION(_streams, _sgi, \
- BW2VBPS(_bw, 1170, 540, 260)), \
+ BW2VBPS(_bw, 1170, 540, 260)) >> _s, \
MCS_DURATION(_streams, _sgi, \
- BW2VBPS(_bw, 1404, 648, 312)), \
+ BW2VBPS(_bw, 1404, 648, 312)) >> _s, \
MCS_DURATION(_streams, _sgi, \
- BW2VBPS(_bw, 1560, 720, 346)) \
+ BW2VBPS(_bw, 1560, 720, 346)) >> _s \
} \
}
@@ -121,19 +123,20 @@
(CCK_DURATION((_bitrate > 10 ? 20 : 10), false, 60) + \
CCK_DURATION(_bitrate, _short, AVG_PKT_SIZE))
-#define CCK_DURATION_LIST(_short) \
- CCK_ACK_DURATION(10, _short), \
- CCK_ACK_DURATION(20, _short), \
- CCK_ACK_DURATION(55, _short), \
- CCK_ACK_DURATION(110, _short)
+#define CCK_DURATION_LIST(_short, _s) \
+ CCK_ACK_DURATION(10, _short) >> _s, \
+ CCK_ACK_DURATION(20, _short) >> _s, \
+ CCK_ACK_DURATION(55, _short) >> _s, \
+ CCK_ACK_DURATION(110, _short) >> _s
-#define CCK_GROUP \
+#define CCK_GROUP(_s) \
[MINSTREL_CCK_GROUP] = { \
.streams = 0, \
.flags = 0, \
+ .shift = _s, \
.duration = { \
- CCK_DURATION_LIST(false), \
- CCK_DURATION_LIST(true) \
+ CCK_DURATION_LIST(false, _s), \
+ CCK_DURATION_LIST(true, _s) \
} \
}
@@ -151,47 +154,47 @@ MODULE_PARM_DESC(minstrel_vht_only,
* BW -> SGI -> #streams
*/
const struct mcs_group minstrel_mcs_groups[] = {
- MCS_GROUP(1, 0, BW_20),
- MCS_GROUP(2, 0, BW_20),
- MCS_GROUP(3, 0, BW_20),
-
- MCS_GROUP(1, 1, BW_20),
- MCS_GROUP(2, 1, BW_20),
- MCS_GROUP(3, 1, BW_20),
-
- MCS_GROUP(1, 0, BW_40),
- MCS_GROUP(2, 0, BW_40),
- MCS_GROUP(3, 0, BW_40),
-
- MCS_GROUP(1, 1, BW_40),
- MCS_GROUP(2, 1, BW_40),
- MCS_GROUP(3, 1, BW_40),
-
- CCK_GROUP,
-
- VHT_GROUP(1, 0, BW_20),
- VHT_GROUP(2, 0, BW_20),
- VHT_GROUP(3, 0, BW_20),
-
- VHT_GROUP(1, 1, BW_20),
- VHT_GROUP(2, 1, BW_20),
- VHT_GROUP(3, 1, BW_20),
-
- VHT_GROUP(1, 0, BW_40),
- VHT_GROUP(2, 0, BW_40),
- VHT_GROUP(3, 0, BW_40),
-
- VHT_GROUP(1, 1, BW_40),
- VHT_GROUP(2, 1, BW_40),
- VHT_GROUP(3, 1, BW_40),
-
- VHT_GROUP(1, 0, BW_80),
- VHT_GROUP(2, 0, BW_80),
- VHT_GROUP(3, 0, BW_80),
-
- VHT_GROUP(1, 1, BW_80),
- VHT_GROUP(2, 1, BW_80),
- VHT_GROUP(3, 1, BW_80),
+ MCS_GROUP(1, 0, BW_20, 5),
+ MCS_GROUP(2, 0, BW_20, 4),
+ MCS_GROUP(3, 0, BW_20, 4),
+
+ MCS_GROUP(1, 1, BW_20, 5),
+ MCS_GROUP(2, 1, BW_20, 4),
+ MCS_GROUP(3, 1, BW_20, 4),
+
+ MCS_GROUP(1, 0, BW_40, 4),
+ MCS_GROUP(2, 0, BW_40, 4),
+ MCS_GROUP(3, 0, BW_40, 4),
+
+ MCS_GROUP(1, 1, BW_40, 4),
+ MCS_GROUP(2, 1, BW_40, 4),
+ MCS_GROUP(3, 1, BW_40, 4),
+
+ CCK_GROUP(8),
+
+ VHT_GROUP(1, 0, BW_20, 5),
+ VHT_GROUP(2, 0, BW_20, 4),
+ VHT_GROUP(3, 0, BW_20, 4),
+
+ VHT_GROUP(1, 1, BW_20, 5),
+ VHT_GROUP(2, 1, BW_20, 4),
+ VHT_GROUP(3, 1, BW_20, 4),
+
+ VHT_GROUP(1, 0, BW_40, 4),
+ VHT_GROUP(2, 0, BW_40, 4),
+ VHT_GROUP(3, 0, BW_40, 4),
+
+ VHT_GROUP(1, 1, BW_40, 4),
+ VHT_GROUP(2, 1, BW_40, 4),
+ VHT_GROUP(3, 1, BW_40, 4),
+
+ VHT_GROUP(1, 0, BW_80, 4),
+ VHT_GROUP(2, 0, BW_80, 4),
+ VHT_GROUP(3, 0, BW_80, 4),
+
+ VHT_GROUP(1, 1, BW_80, 4),
+ VHT_GROUP(2, 1, BW_80, 4),
+ VHT_GROUP(3, 1, BW_80, 4),
};
static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES] __read_mostly;
@@ -307,7 +310,8 @@ minstrel_ht_get_tp_avg(struct minstrel_h
if (group != MINSTREL_CCK_GROUP)
nsecs = 1000 * mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len);
- nsecs += minstrel_mcs_groups[group].duration[rate];
+ nsecs += minstrel_mcs_groups[group].duration[rate] <<
+ minstrel_mcs_groups[group].shift;
/*
* For the throughput calculation, limit the probability value to 90% to
@@ -755,12 +759,19 @@ minstrel_ht_tx_status(void *priv, struct
minstrel_ht_update_rates(mp, mi);
}
+static inline int
+minstrel_get_duration(int index)
+{
+ const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
+ unsigned int duration = group->duration[index % MCS_GROUP_RATES];
+ return duration << group->shift;
+}
+
static void
minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
int index)
{
struct minstrel_rate_stats *mrs;
- const struct mcs_group *group;
unsigned int tx_time, tx_time_rtscts, tx_time_data;
unsigned int cw = mp->cw_min;
unsigned int ctime = 0;
@@ -779,8 +790,7 @@ minstrel_calc_retransmit(struct minstrel
mrs->retry_count_rtscts = 2;
mrs->retry_updated = true;
- group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
- tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len / 1000;
+ tx_time_data = minstrel_get_duration(index) * ampdu_len / 1000;
/* Contention time for first 2 tries */
ctime = (t_slot * cw) >> 1;
@@ -874,20 +884,24 @@ minstrel_ht_get_max_amsdu_len(struct min
int group = mi->max_prob_rate / MCS_GROUP_RATES;
const struct mcs_group *g = &minstrel_mcs_groups[group];
int rate = mi->max_prob_rate % MCS_GROUP_RATES;
+ unsigned int duration;
/* Disable A-MSDU if max_prob_rate is bad */
if (mi->groups[group].rates[rate].prob_ewma < MINSTREL_FRAC(50, 100))
return 1;
+ duration = g->duration[rate];
+ duration <<= g->shift;
+
/* If the rate is slower than single-stream MCS1, make A-MSDU limit small */
- if (g->duration[rate] > MCS_DURATION(1, 0, 52))
+ if (duration > MCS_DURATION(1, 0, 52))
return 500;
/*
* If the rate is slower than single-stream MCS4, limit A-MSDU to usual
* data packet size
*/
- if (g->duration[rate] > MCS_DURATION(1, 0, 104))
+ if (duration > MCS_DURATION(1, 0, 104))
return 1600;
/*
@@ -895,7 +909,7 @@ minstrel_ht_get_max_amsdu_len(struct min
* rate success probability is less than 75%, limit A-MSDU to twice the usual
* data packet size
*/
- if (g->duration[rate] > MCS_DURATION(1, 0, 260) ||
+ if (duration > MCS_DURATION(1, 0, 260) ||
(minstrel_ht_get_prob_ewma(mi, mi->max_tp_rate[0]) <
MINSTREL_FRAC(75, 100)))
return 3200;
@@ -942,13 +956,6 @@ minstrel_ht_update_rates(struct minstrel
rate_control_set_rates(mp->hw, mi->sta, rates);
}
-static inline int
-minstrel_get_duration(int index)
-{
- const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
- return group->duration[index % MCS_GROUP_RATES];
-}
-
static int
minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
{
--- a/net/mac80211/rc80211_minstrel_ht.h
+++ b/net/mac80211/rc80211_minstrel_ht.h
@@ -33,9 +33,10 @@
#define MCS_GROUP_RATES 10
struct mcs_group {
- u32 flags;
- unsigned int streams;
- unsigned int duration[MCS_GROUP_RATES];
+ u16 flags;
+ u8 streams;
+ u8 shift;
+ u16 duration[MCS_GROUP_RATES];
};
extern const struct mcs_group minstrel_mcs_groups[];
--- a/net/mac80211/rc80211_minstrel_ht_debugfs.c
+++ b/net/mac80211/rc80211_minstrel_ht_debugfs.c
@@ -58,6 +58,7 @@ minstrel_ht_stats_dump(struct minstrel_h
static const int bitrates[4] = { 10, 20, 55, 110 };
int idx = i * MCS_GROUP_RATES + j;
unsigned int prob_ewmsd;
+ unsigned int duration;
if (!(mi->supported[i] & BIT(j)))
continue;
@@ -95,7 +96,9 @@ minstrel_ht_stats_dump(struct minstrel_h
p += sprintf(p, " %3u ", idx);
/* tx_time[rate(i)] in usec */
- tx_time = DIV_ROUND_CLOSEST(mg->duration[j], 1000);
+ duration = mg->duration[j];
+ duration <<= mg->shift;
+ tx_time = DIV_ROUND_CLOSEST(duration, 1000);
p += sprintf(p, "%6u ", tx_time);
tp_max = minstrel_ht_get_tp_avg(mi, i, j, MINSTREL_FRAC(100, 100));
@@ -204,6 +207,7 @@ minstrel_ht_stats_csv_dump(struct minstr
static const int bitrates[4] = { 10, 20, 55, 110 };
int idx = i * MCS_GROUP_RATES + j;
unsigned int prob_ewmsd;
+ unsigned int duration;
if (!(mi->supported[i] & BIT(j)))
continue;
@@ -238,7 +242,10 @@ minstrel_ht_stats_csv_dump(struct minstr
}
p += sprintf(p, "%u,", idx);
- tx_time = DIV_ROUND_CLOSEST(mg->duration[j], 1000);
+
+ duration = mg->duration[j];
+ duration <<= mg->shift;
+ tx_time = DIV_ROUND_CLOSEST(duration, 1000);
p += sprintf(p, "%u,", tx_time);
tp_max = minstrel_ht_get_tp_avg(mi, i, j, MINSTREL_FRAC(100, 100));