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mac80211: minstrel_ht: add basic support for VHT rates <= 3SS@80MHz
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When the new CONFIG_MAC80211_RC_MINSTREL_VHT is not set (default 'N'),
there is no behavioral change including in sampling and MCS_GROUP_RATES
remains 8.
Otherwise MCS_GROUP_RATES is 10, and a module parameter *vht_only*
(default 'true'), restricts the rates selection to VHT when VHT is
supported.

Regarding the debugfs stats buffer:
It is explicitly increased from 8k to 32k to fit every rates incl. when
both HT and VHT rates are enabled, as for the format, before:
type           rate     tpt eprob *prob ret  *ok(*cum)        ok(      cum)
HT20/LGI ABCDP MCS0     0.0   0.0   0.0   1    0(   0)         0(        0)
after:
 type           rate      tpt eprob *prob ret  *ok(*cum)        ok(      cum)
 HT20/LGI ABCDP MCS0      0.0   0.0   0.0   1    0(   0)         0(        0)
VHT40/LGI       MCS5/2    0.0   0.0   0.0   0    0(   0)         0(        0)

Signed-off-by: Karl Beldan <karl.beldan@rivierawaves.com>
Cc: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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Karl Beldan authored and Johannes Berg committed Oct 21, 2014
1 parent 3ec373c commit 9208247
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Showing 4 changed files with 241 additions and 22 deletions.
7 changes: 7 additions & 0 deletions net/mac80211/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,13 @@ config MAC80211_RC_MINSTREL_HT
---help---
This option enables the 'minstrel_ht' TX rate control algorithm

config MAC80211_RC_MINSTREL_VHT
bool "Minstrel 802.11ac support" if EXPERT
depends on MAC80211_RC_MINSTREL_HT
default n
---help---
This option enables VHT in the 'minstrel_ht' TX rate control algorithm

choice
prompt "Default rate control algorithm"
depends on MAC80211_HAS_RC
Expand Down
216 changes: 204 additions & 12 deletions net/mac80211/rc80211_minstrel_ht.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,7 @@
#include <linux/skbuff.h>
#include <linux/debugfs.h>
#include <linux/random.h>
#include <linux/moduleparam.h>
#include <linux/ieee80211.h>
#include <net/mac80211.h>
#include "rate.h"
Expand All @@ -36,6 +37,7 @@

#define BW_20 0
#define BW_40 1
#define BW_80 2

/*
* Define group sort order: HT40 -> SGI -> #streams
Expand Down Expand Up @@ -66,6 +68,47 @@
} \
}

#define VHT_GROUP_IDX(_streams, _sgi, _bw) \
(MINSTREL_VHT_GROUP_0 + \
MINSTREL_MAX_STREAMS * 2 * (_bw) + \
MINSTREL_MAX_STREAMS * (_sgi) + \
(_streams) - 1)

#define BW2VBPS(_bw, r3, r2, r1) \
(_bw == BW_80 ? r3 : _bw == BW_40 ? r2 : r1)

#define VHT_GROUP(_streams, _sgi, _bw) \
[VHT_GROUP_IDX(_streams, _sgi, _bw)] = { \
.streams = _streams, \
.flags = \
IEEE80211_TX_RC_VHT_MCS | \
(_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) | \
(_bw == BW_80 ? IEEE80211_TX_RC_80_MHZ_WIDTH : \
_bw == BW_40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0), \
.duration = { \
MCS_DURATION(_streams, _sgi, \
BW2VBPS(_bw, 117, 54, 26)), \
MCS_DURATION(_streams, _sgi, \
BW2VBPS(_bw, 234, 108, 52)), \
MCS_DURATION(_streams, _sgi, \
BW2VBPS(_bw, 351, 162, 78)), \
MCS_DURATION(_streams, _sgi, \
BW2VBPS(_bw, 468, 216, 104)), \
MCS_DURATION(_streams, _sgi, \
BW2VBPS(_bw, 702, 324, 156)), \
MCS_DURATION(_streams, _sgi, \
BW2VBPS(_bw, 936, 432, 208)), \
MCS_DURATION(_streams, _sgi, \
BW2VBPS(_bw, 1053, 486, 234)), \
MCS_DURATION(_streams, _sgi, \
BW2VBPS(_bw, 1170, 540, 260)), \
MCS_DURATION(_streams, _sgi, \
BW2VBPS(_bw, 1404, 648, 312)), \
MCS_DURATION(_streams, _sgi, \
BW2VBPS(_bw, 1560, 720, 346)) \
} \
}

#define CCK_DURATION(_bitrate, _short, _len) \
(1000 * (10 /* SIFS */ + \
(_short ? 72 + 24 : 144 + 48) + \
Expand All @@ -91,6 +134,13 @@
} \
}

#ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
static bool minstrel_vht_only = true;
module_param(minstrel_vht_only, bool, 0644);
MODULE_PARM_DESC(minstrel_vht_only,
"Use only VHT rates when VHT is supported by sta.");
#endif

/*
* To enable sufficiently targeted rate sampling, MCS rates are divided into
* groups, based on the number of streams and flags (HT40, SGI) that they
Expand Down Expand Up @@ -124,15 +174,91 @@ const struct mcs_group minstrel_mcs_groups[] = {
MCS_GROUP(3, 1, BW_40),
#endif

CCK_GROUP
};
CCK_GROUP,

#ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
VHT_GROUP(1, 0, BW_20),
VHT_GROUP(2, 0, BW_20),
#if MINSTREL_MAX_STREAMS >= 3
VHT_GROUP(3, 0, BW_20),
#endif

VHT_GROUP(1, 1, BW_20),
VHT_GROUP(2, 1, BW_20),
#if MINSTREL_MAX_STREAMS >= 3
VHT_GROUP(3, 1, BW_20),
#endif

VHT_GROUP(1, 0, BW_40),
VHT_GROUP(2, 0, BW_40),
#if MINSTREL_MAX_STREAMS >= 3
VHT_GROUP(3, 0, BW_40),
#endif

VHT_GROUP(1, 1, BW_40),
VHT_GROUP(2, 1, BW_40),
#if MINSTREL_MAX_STREAMS >= 3
VHT_GROUP(3, 1, BW_40),
#endif

VHT_GROUP(1, 0, BW_80),
VHT_GROUP(2, 0, BW_80),
#if MINSTREL_MAX_STREAMS >= 3
VHT_GROUP(3, 0, BW_80),
#endif

VHT_GROUP(1, 1, BW_80),
VHT_GROUP(2, 1, BW_80),
#if MINSTREL_MAX_STREAMS >= 3
VHT_GROUP(3, 1, BW_80),
#endif
#endif
};

static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES] __read_mostly;

static void
minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi);

/*
* Some VHT MCSes are invalid (when Ndbps / Nes is not an integer)
* e.g for MCS9@20MHzx1Nss: Ndbps=8x52*(5/6) Nes=1
*
* Returns the valid mcs map for struct minstrel_mcs_group_data.supported
*/
static u16
minstrel_get_valid_vht_rates(int bw, int nss, __le16 mcs_map)
{
u16 mask = 0;

if (bw == BW_20) {
if (nss != 3 && nss != 6)
mask = BIT(9);
} else if (bw == BW_80) {
if (nss == 3 || nss == 7)
mask = BIT(6);
else if (nss == 6)
mask = BIT(9);
} else {
WARN_ON(bw != BW_40);
}

switch ((le16_to_cpu(mcs_map) >> (2 * (nss - 1))) & 3) {
case IEEE80211_VHT_MCS_SUPPORT_0_7:
mask |= 0x300;
break;
case IEEE80211_VHT_MCS_SUPPORT_0_8:
mask |= 0x200;
break;
case IEEE80211_VHT_MCS_SUPPORT_0_9:
break;
default:
mask = 0x3ff;
}

return 0x3ff & ~mask;
}

/*
* Look up an MCS group index based on mac80211 rate information
*/
Expand All @@ -144,6 +270,15 @@ minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
!!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH));
}

static int
minstrel_vht_get_group_idx(struct ieee80211_tx_rate *rate)
{
return VHT_GROUP_IDX(ieee80211_rate_get_vht_nss(rate),
!!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
!!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH) +
2*!!(rate->flags & IEEE80211_TX_RC_80_MHZ_WIDTH));
}

static struct minstrel_rate_stats *
minstrel_ht_get_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
struct ieee80211_tx_rate *rate)
Expand All @@ -153,6 +288,9 @@ minstrel_ht_get_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
if (rate->flags & IEEE80211_TX_RC_MCS) {
group = minstrel_ht_get_group_idx(rate);
idx = rate->idx % 8;
} else if (rate->flags & IEEE80211_TX_RC_VHT_MCS) {
group = minstrel_vht_get_group_idx(rate);
idx = ieee80211_rate_get_vht_mcs(rate);
} else {
group = MINSTREL_CCK_GROUP;

Expand Down Expand Up @@ -489,7 +627,8 @@ minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rat
if (!rate->count)
return false;

if (rate->flags & IEEE80211_TX_RC_MCS)
if (rate->flags & IEEE80211_TX_RC_MCS ||
rate->flags & IEEE80211_TX_RC_VHT_MCS)
return true;

return rate->idx == mp->cck_rates[0] ||
Expand Down Expand Up @@ -736,6 +875,9 @@ minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,

if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP)
idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
else if (flags & IEEE80211_TX_RC_VHT_MCS)
idx = ((group->streams - 1) << 4) |
((index % MCS_GROUP_RATES) & 0xF);
else
idx = index % MCS_GROUP_RATES + (group->streams - 1) * 8;

Expand Down Expand Up @@ -917,6 +1059,9 @@ minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
if (sample_idx / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
int idx = sample_idx % ARRAY_SIZE(mp->cck_rates);
rate->idx = mp->cck_rates[idx];
} else if (sample_group->flags & IEEE80211_TX_RC_VHT_MCS) {
ieee80211_rate_set_vht(rate, sample_idx % MCS_GROUP_RATES,
sample_group->streams);
} else {
rate->idx = sample_idx % MCS_GROUP_RATES +
(sample_group->streams - 1) * 8;
Expand Down Expand Up @@ -962,6 +1107,8 @@ minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
struct minstrel_ht_sta *mi = &msp->ht;
struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
u16 sta_cap = sta->ht_cap.cap;
struct ieee80211_sta_vht_cap *vht_cap = &sta->vht_cap;
int use_vht;
int n_supported = 0;
int ack_dur;
int stbc;
Expand All @@ -973,6 +1120,13 @@ minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,

BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) != MINSTREL_GROUPS_NB);

#ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
if (vht_cap->vht_supported)
use_vht = vht_cap->vht_mcs.tx_mcs_map != cpu_to_le16(~0);
else
#endif
use_vht = 0;

msp->is_ht = true;
memset(mi, 0, sizeof(*mi));

Expand All @@ -996,15 +1150,19 @@ minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
}
mi->sample_tries = 4;

stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
IEEE80211_HT_CAP_RX_STBC_SHIFT;
mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
/* TODO tx_flags for vht - ATM the RC API is not fine-grained enough */
if (!use_vht) {
stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
IEEE80211_HT_CAP_RX_STBC_SHIFT;
mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;

if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
}

for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
u32 gflags = minstrel_mcs_groups[i].flags;
int bw, nss;

mi->groups[i].supported = 0;
if (i == MINSTREL_CCK_GROUP) {
Expand All @@ -1026,13 +1184,47 @@ minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
sta->bandwidth < IEEE80211_STA_RX_BW_40)
continue;

nss = minstrel_mcs_groups[i].streams;

/* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
if (sta->smps_mode == IEEE80211_SMPS_STATIC &&
minstrel_mcs_groups[i].streams > 1)
if (sta->smps_mode == IEEE80211_SMPS_STATIC && nss > 1)
continue;

/* HT rate */
if (gflags & IEEE80211_TX_RC_MCS) {
#ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
if (minstrel_vht_only)
continue;
#endif
mi->groups[i].supported = mcs->rx_mask[nss - 1];
if (mi->groups[i].supported)
n_supported++;
continue;
}

/* VHT rate */
if (!vht_cap->vht_supported ||
WARN_ON(!(gflags & IEEE80211_TX_RC_VHT_MCS)) ||
WARN_ON(gflags & IEEE80211_TX_RC_160_MHZ_WIDTH))
continue;

mi->groups[i].supported =
mcs->rx_mask[minstrel_mcs_groups[i].streams - 1];
if (gflags & IEEE80211_TX_RC_80_MHZ_WIDTH) {
if (sta->bandwidth < IEEE80211_STA_RX_BW_80 ||
((gflags & IEEE80211_TX_RC_SHORT_GI) &&
!(vht_cap->cap & IEEE80211_VHT_CAP_SHORT_GI_80))) {
continue;
}
}

if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH)
bw = BW_40;
else if (gflags & IEEE80211_TX_RC_80_MHZ_WIDTH)
bw = BW_80;
else
bw = BW_20;

mi->groups[i].supported = minstrel_get_valid_vht_rates(bw, nss,
vht_cap->vht_mcs.tx_mcs_map);

if (mi->groups[i].supported)
n_supported++;
Expand Down
17 changes: 15 additions & 2 deletions net/mac80211/rc80211_minstrel_ht.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -15,17 +15,30 @@
*/
#define MINSTREL_MAX_STREAMS 3
#define MINSTREL_HT_STREAM_GROUPS 4 /* BW(=2) * SGI(=2) */
#ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
#define MINSTREL_VHT_STREAM_GROUPS 6 /* BW(=3) * SGI(=2) */
#else
#define MINSTREL_VHT_STREAM_GROUPS 0
#endif

#define MINSTREL_HT_GROUPS_NB (MINSTREL_MAX_STREAMS * \
MINSTREL_HT_STREAM_GROUPS)
#define MINSTREL_VHT_GROUPS_NB (MINSTREL_MAX_STREAMS * \
MINSTREL_VHT_STREAM_GROUPS)
#define MINSTREL_CCK_GROUPS_NB 1
#define MINSTREL_GROUPS_NB (MINSTREL_HT_GROUPS_NB + \
MINSTREL_VHT_GROUPS_NB + \
MINSTREL_CCK_GROUPS_NB)

#define MINSTREL_HT_GROUP_0 0
#define MINSTREL_CCK_GROUP (MINSTREL_HT_GROUP_0 + MINSTREL_HT_GROUPS_NB)
#define MINSTREL_VHT_GROUP_0 (MINSTREL_CCK_GROUP + 1)

#define MCS_GROUP_RATES 8
#ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
#define MCS_GROUP_RATES 10
#else
#define MCS_GROUP_RATES 8
#endif

struct mcs_group {
u32 flags;
Expand All @@ -40,7 +53,7 @@ struct minstrel_mcs_group_data {
u8 column;

/* bitfield of supported MCS rates of this group */
u8 supported;
u16 supported;

/* sorted rate set within a MCS group*/
u16 max_group_tp_rate[MAX_THR_RATES];
Expand Down
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