+++ /dev/null
-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, 0, BW_20, 5),
-+ MCS_GROUP(2, 0, BW_20, 4),
-+ MCS_GROUP(3, 0, BW_20, 4),
-
-- MCS_GROUP(1, 1, BW_20),
-- MCS_GROUP(2, 1, BW_20),
-- MCS_GROUP(3, 1, BW_20),
-+ 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),
-- MCS_GROUP(2, 0, BW_40),
-- MCS_GROUP(3, 0, BW_40),
-+ 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),
-- MCS_GROUP(2, 1, BW_40),
-- MCS_GROUP(3, 1, BW_40),
-+ MCS_GROUP(1, 1, BW_40, 4),
-+ MCS_GROUP(2, 1, BW_40, 4),
-+ MCS_GROUP(3, 1, BW_40, 4),
-
-- CCK_GROUP,
-+ CCK_GROUP(8),
-
-- VHT_GROUP(1, 0, BW_20),
-- VHT_GROUP(2, 0, BW_20),
-- VHT_GROUP(3, 0, BW_20),
-+ 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),
-- VHT_GROUP(2, 1, BW_20),
-- VHT_GROUP(3, 1, BW_20),
-+ 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),
-- VHT_GROUP(2, 0, BW_40),
-- VHT_GROUP(3, 0, BW_40),
-+ 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),
-- VHT_GROUP(2, 1, BW_40),
-- VHT_GROUP(3, 1, BW_40),
-+ 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),
-- VHT_GROUP(2, 0, BW_80),
-- VHT_GROUP(3, 0, BW_80),
-+ 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),
-- VHT_GROUP(2, 1, BW_80),
-- VHT_GROUP(3, 1, BW_80),
-+ 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));
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