mac80211: add the minstrel_ht rate control algorithm

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/Kconfig

@@ -33,6 +33,13 @@ config MAC80211_RC_MINSTREL
 	---help---
 	  This option enables the 'minstrel' TX rate control algorithm
 
+config MAC80211_RC_MINSTREL_HT
+	bool "Minstrel 802.11n support" if EMBEDDED
+	depends on MAC80211_RC_MINSTREL
+	default y
+	---help---
+	  This option enables the 'minstrel_ht' TX rate control algorithm
+
 choice
 	prompt "Default rate control algorithm"
 	depends on MAC80211_HAS_RC

net/mac80211/Makefile

@@ -51,7 +51,11 @@ rc80211_pid-$(CONFIG_MAC80211_DEBUGFS) += rc80211_pid_debugfs.o
 rc80211_minstrel-y := rc80211_minstrel.o
 rc80211_minstrel-$(CONFIG_MAC80211_DEBUGFS) += rc80211_minstrel_debugfs.o
 
+rc80211_minstrel_ht-y := rc80211_minstrel_ht.o
+rc80211_minstrel_ht-$(CONFIG_MAC80211_DEBUGFS) += rc80211_minstrel_ht_debugfs.o
+
 mac80211-$(CONFIG_MAC80211_RC_PID) += $(rc80211_pid-y)
 mac80211-$(CONFIG_MAC80211_RC_MINSTREL) += $(rc80211_minstrel-y)
+mac80211-$(CONFIG_MAC80211_RC_MINSTREL_HT) += $(rc80211_minstrel_ht-y)
 
 ccflags-y += -D__CHECK_ENDIAN__

net/mac80211/main.c

@@ -704,6 +704,10 @@ static int __init ieee80211_init(void)
 	if (ret)
 		return ret;
 
+	ret = rc80211_minstrel_ht_init();
+	if (ret)
+		goto err_minstrel;
+
 	ret = rc80211_pid_init();
 	if (ret)
 		goto err_pid;
@@ -716,6 +720,8 @@ static int __init ieee80211_init(void)
  err_netdev:
 	rc80211_pid_exit();
  err_pid:
+	rc80211_minstrel_ht_exit();
+ err_minstrel:
 	rc80211_minstrel_exit();
 
 	return ret;
@@ -724,6 +730,7 @@ static int __init ieee80211_init(void)
 static void __exit ieee80211_exit(void)
 {
 	rc80211_pid_exit();
+	rc80211_minstrel_ht_exit();
 	rc80211_minstrel_exit();
 
 	/*

net/mac80211/rate.h

@@ -147,5 +147,18 @@ static inline void rc80211_minstrel_exit(void)
 }
 #endif
 
+#ifdef CONFIG_MAC80211_RC_MINSTREL_HT
+extern int rc80211_minstrel_ht_init(void);
+extern void rc80211_minstrel_ht_exit(void);
+#else
+static inline int rc80211_minstrel_ht_init(void)
+{
+	return 0;
+}
+static inline void rc80211_minstrel_ht_exit(void)
+{
+}
+#endif
+
 
 #endif /* IEEE80211_RATE_H */

net/mac80211/rc80211_minstrel_ht.h

+/*
+ * Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __RC_MINSTREL_HT_H
+#define __RC_MINSTREL_HT_H
+
+/*
+ * The number of streams can be changed to 2 to reduce code
+ * size and memory footprint.
+ */
+#define MINSTREL_MAX_STREAMS	3
+#define MINSTREL_STREAM_GROUPS	4
+
+/* scaled fraction values */
+#define MINSTREL_SCALE	16
+#define MINSTREL_FRAC(val, div) (((val) << MINSTREL_SCALE) / div)
+#define MINSTREL_TRUNC(val) ((val) >> MINSTREL_SCALE)
+
+#define MCS_GROUP_RATES	8
+
+struct mcs_group {
+	u32 flags;
+	unsigned int streams;
+	unsigned int duration[MCS_GROUP_RATES];
+};
+
+struct minstrel_rate_stats {
+	/* current / last sampling period attempts/success counters */
+	unsigned int attempts, last_attempts;
+	unsigned int success, last_success;
+
+	/* total attempts/success counters */
+	u64 att_hist, succ_hist;
+
+	/* current throughput */
+	unsigned int cur_tp;
+
+	/* packet delivery probabilities */
+	unsigned int cur_prob, probability;
+
+	/* maximum retry counts */
+	unsigned int retry_count;
+	unsigned int retry_count_rtscts;
+
+	bool retry_updated;
+	u8 sample_skipped;
+};
+
+struct minstrel_mcs_group_data {
+	u8 index;
+	u8 column;
+
+	/* bitfield of supported MCS rates of this group */
+	u8 supported;
+
+	/* selected primary rates */
+	unsigned int max_tp_rate;
+	unsigned int max_tp_rate2;
+	unsigned int max_prob_rate;
+
+	/* MCS rate statistics */
+	struct minstrel_rate_stats rates[MCS_GROUP_RATES];
+};
+
+struct minstrel_ht_sta {
+	/* ampdu length (average, per sampling interval) */
+	unsigned int ampdu_len;
+	unsigned int ampdu_packets;
+
+	/* ampdu length (EWMA) */
+	unsigned int avg_ampdu_len;
+
+	/* best throughput rate */
+	unsigned int max_tp_rate;
+
+	/* second best throughput rate */
+	unsigned int max_tp_rate2;
+
+	/* best probability rate */
+	unsigned int max_prob_rate;
+
+	/* time of last status update */
+	unsigned long stats_update;
+
+	/* overhead time in usec for each frame */
+	unsigned int overhead;
+	unsigned int overhead_rtscts;
+
+	unsigned int total_packets;
+	unsigned int sample_packets;
+
+	/* tx flags to add for frames for this sta */
+	u32 tx_flags;
+
+	u8 sample_wait;
+	u8 sample_tries;
+	u8 sample_count;
+	u8 sample_slow;
+
+	/* current MCS group to be sampled */
+	u8 sample_group;
+
+	/* MCS rate group info and statistics */
+	struct minstrel_mcs_group_data groups[MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS];
+};
+
+struct minstrel_ht_sta_priv {
+	union {
+		struct minstrel_ht_sta ht;
+		struct minstrel_sta_info legacy;
+	};
+#ifdef CONFIG_MAC80211_DEBUGFS
+	struct dentry *dbg_stats;
+#endif
+	void *ratelist;
+	void *sample_table;
+	bool is_ht;
+};
+
+void minstrel_ht_add_sta_debugfs(void *priv, void *priv_sta, struct dentry *dir);
+void minstrel_ht_remove_sta_debugfs(void *priv, void *priv_sta);
+
+#endif

net/mac80211/rc80211_minstrel_ht_debugfs.c

+/*
+ * Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/netdevice.h>
+#include <linux/types.h>
+#include <linux/skbuff.h>
+#include <linux/debugfs.h>
+#include <linux/ieee80211.h>
+#include <net/mac80211.h>
+#include "rc80211_minstrel.h"
+#include "rc80211_minstrel_ht.h"
+
+extern const struct mcs_group minstrel_mcs_groups[];
+
+static int
+minstrel_ht_stats_open(struct inode *inode, struct file *file)
+{
+	struct minstrel_ht_sta_priv *msp = inode->i_private;
+	struct minstrel_ht_sta *mi = &msp->ht;
+	struct minstrel_debugfs_info *ms;
+	unsigned int i, j, tp, prob, eprob;
+	char *p;
+	int ret;
+
+	if (!msp->is_ht) {
+		inode->i_private = &msp->legacy;
+		ret = minstrel_stats_open(inode, file);
+		inode->i_private = msp;
+		return ret;
+	}
+
+	ms = kmalloc(sizeof(*ms) + 8192, GFP_KERNEL);
+	if (!ms)
+		return -ENOMEM;
+
+	file->private_data = ms;
+	p = ms->buf;
+	p += sprintf(p, "type      rate     throughput  ewma prob   this prob  "
+			"this succ/attempt   success    attempts\n");
+	for (i = 0; i < MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS; i++) {
+		char htmode = '2';
+		char gimode = 'L';
+
+		if (!mi->groups[i].supported)
+			continue;
+
+		if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
+			htmode = '4';
+		if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI)
+			gimode = 'S';
+
+		for (j = 0; j < MCS_GROUP_RATES; j++) {
+			struct minstrel_rate_stats *mr = &mi->groups[i].rates[j];
+			int idx = i * MCS_GROUP_RATES + j;
+
+			if (!(mi->groups[i].supported & BIT(j)))
+				continue;
+
+			p += sprintf(p, "HT%c0/%cGI ", htmode, gimode);
+
+			*(p++) = (idx == mi->max_tp_rate) ? 'T' : ' ';
+			*(p++) = (idx == mi->max_tp_rate2) ? 't' : ' ';
+			*(p++) = (idx == mi->max_prob_rate) ? 'P' : ' ';
+			p += sprintf(p, "MCS%-2u", (minstrel_mcs_groups[i].streams - 1) *
+					MCS_GROUP_RATES + j);
+
+			tp = mr->cur_tp / 10;
+			prob = MINSTREL_TRUNC(mr->cur_prob * 1000);
+			eprob = MINSTREL_TRUNC(mr->probability * 1000);
+
+			p += sprintf(p, "  %6u.%1u   %6u.%1u   %6u.%1u        "
+					"%3u(%3u)   %8llu    %8llu\n",
+					tp / 10, tp % 10,
+					eprob / 10, eprob % 10,
+					prob / 10, prob % 10,
+					mr->last_success,
+					mr->last_attempts,
+					(unsigned long long)mr->succ_hist,
+					(unsigned long long)mr->att_hist);
+		}
+	}
+	p += sprintf(p, "\nTotal packet count::    ideal %d      "
+			"lookaround %d\n",
+			max(0, (int) mi->total_packets - (int) mi->sample_packets),
+			mi->sample_packets);
+	p += sprintf(p, "Average A-MPDU length: %d.%d\n",
+		MINSTREL_TRUNC(mi->avg_ampdu_len),
+		MINSTREL_TRUNC(mi->avg_ampdu_len * 10) % 10);
+	ms->len = p - ms->buf;
+
+	return 0;
+}
+
+static const struct file_operations minstrel_ht_stat_fops = {
+	.owner = THIS_MODULE,
+	.open = minstrel_ht_stats_open,
+	.read = minstrel_stats_read,
+	.release = minstrel_stats_release,
+};
+
+void
+minstrel_ht_add_sta_debugfs(void *priv, void *priv_sta, struct dentry *dir)
+{
+	struct minstrel_ht_sta_priv *msp = priv_sta;
+
+	msp->dbg_stats = debugfs_create_file("rc_stats", S_IRUGO, dir, msp,
+			&minstrel_ht_stat_fops);
+}
+
+void
+minstrel_ht_remove_sta_debugfs(void *priv, void *priv_sta)
+{
+	struct minstrel_ht_sta_priv *msp = priv_sta;
+
+	debugfs_remove(msp->dbg_stats);
+}