net80211: add VHT MCS in AMRR rate control

This is a simple implementation, similar to HT, to generate
VHT MCS rates for testing.

I've verified it seems to do the right thing through
MCS 0..9 and NSS 1..2.  It's not very optimal - same issues as
with 11n - but it at least now fully tests the 11ac TX path in
rtwn and the tx rate refactoring.

Differential Revision:	https://reviews.freebsd.org/D48611

2 files changed, 181 insertions, 6 deletions

diff --git a/sys/net80211/ieee80211_amrr.c b/sys/net80211/ieee80211_amrr.c
index 352f8df3a03e..1a06303bd2c9 100644
--- a/sys/net80211/ieee80211_amrr.c
+++ b/sys/net80211/ieee80211_amrr.c
@@ -49,6 +49,7 @@
 
 #include <net80211/ieee80211_var.h>
 #include <net80211/ieee80211_ht.h>
+#include <net80211/ieee80211_vht.h>
 #include <net80211/ieee80211_amrr.h>
 #include <net80211/ieee80211_ratectl.h>
 
@@ -139,6 +140,23 @@ amrr_deinit(struct ieee80211vap *vap)
 }
 
 static void
+amrr_node_init_vht(struct ieee80211_node *ni)
+{
+	struct ieee80211_amrr_node *amn = ni->ni_rctls;
+
+	/* Default to VHT NSS 1 MCS 2; should be reliable! */
+	amn->amn_vht_mcs = 2;
+	amn->amn_vht_nss = 1;
+	ieee80211_node_set_txrate_vht_rate(ni, amn->amn_vht_nss,
+	    amn->amn_vht_mcs);
+
+	IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
+	    "AMRR: VHT: initial rate NSS %d MCS %d",
+	    amn->amn_vht_nss,
+	    amn->amn_vht_mcs);
+}
+
+static void
 amrr_node_init_ht(struct ieee80211_node *ni)
 {
 	const struct ieee80211_rateset *rs;
@@ -237,8 +255,10 @@ amrr_node_init(struct ieee80211_node *ni)
 	amn->amn_success_threshold = amrr->amrr_min_success_threshold;
 	amn->amn_ticks = ticks;
 
-	/* 11n or not? Pick the right rateset */
-	if (ieee80211_ht_check_tx_ht(ni))
+	/* Pick the right rateset */
+	if (ieee80211_vht_check_tx_vht(ni))
+		amrr_node_init_vht(ni);
+	else if (ieee80211_ht_check_tx_ht(ni))
 		amrr_node_init_ht(ni);
 	else
 		amrr_node_init_legacy(ni);
@@ -250,6 +270,137 @@ amrr_node_deinit(struct ieee80211_node *ni)
 	IEEE80211_FREE(ni->ni_rctls, M_80211_RATECTL);
 }
 
+static void
+amrr_update_vht_inc(struct ieee80211_node *ni)
+{
+	struct ieee80211_amrr_node *amn = ni->ni_rctls;
+	uint8_t nss, mcs;
+
+	/*
+	 * For now just keep looping over MCS to 9, then NSS up, checking if
+	 * it's valid via ieee80211_vht_node_check_tx_valid_mcs(),
+	 * until we hit max.  This at least tests the VHT MCS rates,
+	 * but definitely is suboptimal (in the same way the 11n MCS selection
+	 * is suboptimal.)
+	 */
+	nss = amn->amn_vht_nss;
+	mcs = amn->amn_vht_mcs;
+
+	while (nss <= 8 && mcs <= 9) {
+		/* Increment MCS 0..9, NSS 1..8 */
+		if (mcs == 9) {
+			mcs = 0;
+			nss++;
+		} else
+			mcs++;
+		if (nss > 8)
+			break;
+
+		if (ieee80211_vht_node_check_tx_valid_mcs(ni, ni->ni_chw, nss,
+		    mcs)) {
+			amn->amn_vht_nss = nss;
+			amn->amn_vht_mcs = mcs;
+			break;
+		}
+	}
+}
+
+static void
+amrr_update_vht_dec(struct ieee80211_node *ni)
+{
+	struct ieee80211_amrr_node *amn = ni->ni_rctls;
+	uint8_t nss, mcs;
+
+	/*
+	 * For now just keep looping over MCS 9 .. 0 then NSS down, checking if
+	 * it's valid via ieee80211_vht_node_check_tx_valid_mcs(),
+	 * until we hit min.  This at least tests the VHT MCS rates,
+	 * but definitely is suboptimal (in the same way the 11n MCS selection
+	 * is suboptimal.
+	 */
+	nss = amn->amn_vht_nss;
+	mcs = amn->amn_vht_mcs;
+
+	while (nss >= 1 && mcs >= 0) {
+
+		if (mcs == 0) {
+			mcs = 9;
+			nss--;
+		} else
+			mcs--;
+		if (nss < 1)
+			break;
+
+		if (ieee80211_vht_node_check_tx_valid_mcs(ni, ni->ni_chw, nss,
+		    mcs)) {
+			amn->amn_vht_nss = nss;
+			amn->amn_vht_mcs = mcs;
+			break;
+		}
+	}
+}
+
+/*
+ * A placeholder / temporary hack VHT rate control.
+ *
+ * Use the available MCS rates at the current node bandwidth
+ * and configured / negotiated MCS rates.
+ */
+static int
+amrr_update_vht(struct ieee80211_node *ni)
+{
+	struct ieee80211_amrr_node *amn = ni->ni_rctls;
+	struct ieee80211_amrr *amrr = ni->ni_vap->iv_rs;
+
+	IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
+	    "AMRR: VHT: current rate NSS %d MCS %d, txcnt=%d, retrycnt=%d",
+	    amn->amn_vht_nss, amn->amn_vht_mcs, amn->amn_txcnt,
+	    amn->amn_retrycnt);
+
+	if (is_success(amn)) {
+		amn->amn_success++;
+		if (amn->amn_success >= amn->amn_success_threshold) {
+			amn->amn_recovery = 1;
+			amn->amn_success = 0;
+
+			IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
+			    "AMRR: VHT: increase rate (txcnt=%d retrycnt=%d)",
+			    amn->amn_txcnt, amn->amn_retrycnt);
+
+			amrr_update_vht_inc(ni);
+		} else {
+			amn->amn_recovery = 0;
+		}
+	} else if (is_failure(amn)) {
+		amn->amn_success = 0;
+
+		if (amn->amn_recovery) {
+			amn->amn_success_threshold *= 2;
+			if (amn->amn_success_threshold >
+			    amrr->amrr_max_success_threshold)
+				amn->amn_success_threshold =
+				    amrr->amrr_max_success_threshold;
+		} else {
+			amn->amn_success_threshold =
+			    amrr->amrr_min_success_threshold;
+		}
+		IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
+		    "AMRR: VHT: decreasing rate (txcnt=%d retrycnt=%d)",
+		    amn->amn_txcnt, amn->amn_retrycnt);
+
+		amrr_update_vht_dec(ni);
+
+		amn->amn_recovery = 0;
+	}
+
+	/* Reset counters */
+	amn->amn_txcnt = 0;
+	amn->amn_retrycnt = 0;
+
+	/* Return 0, not useful anymore */
+	return (0);
+}
+
 static int
 amrr_update_ht(struct ieee80211_amrr *amrr, struct ieee80211_amrr_node *amn,
     struct ieee80211_node *ni)
@@ -382,8 +533,10 @@ amrr_update(struct ieee80211_amrr *amrr, struct ieee80211_amrr_node *amn,
 
 	KASSERT(is_enough(amn), ("txcnt %d", amn->amn_txcnt));
 
-	/* 11n or not? Pick the right rateset */
-	if (ieee80211_ht_check_tx_ht(ni))
+	/* Pick the right rateset */
+	if (ieee80211_vht_check_tx_vht(ni))
+		rix = amrr_update_vht(ni);
+	else if (ieee80211_ht_check_tx_ht(ni))
 		rix = amrr_update_ht(amrr, amn, ni);
 	else
 		rix = amrr_update_legacy(amrr, amn, ni);
@@ -395,6 +548,22 @@ amrr_update(struct ieee80211_amrr *amrr, struct ieee80211_amrr_node *amn,
 	return (rix);
 }
 
+static int
+amrr_rate_vht(struct ieee80211_node *ni)
+{
+	struct ieee80211_amrr *amrr = ni->ni_vap->iv_rs;
+	struct ieee80211_amrr_node *amn = ni->ni_rctls;
+
+	if (is_enough(amn) && (ticks - amn->amn_ticks) > amrr->amrr_interval)
+		amrr_update_vht(ni);
+
+	ieee80211_node_set_txrate_vht_rate(ni, amn->amn_vht_nss,
+	    amn->amn_vht_mcs);
+
+	/* Note: There's no vht rs_rates, and the API doesn't use it anymore */
+	return (0);
+}
+
 /*
  * Return the rate index to use in sending a data frame.
  * Update our internal state if it's been long enough.
@@ -416,9 +585,10 @@ amrr_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg __unused)
 		return 0;
 	}
 
-	amrr = amn->amn_amrr;
+	if (ieee80211_vht_check_tx_vht(ni))
+		return (amrr_rate_vht(ni));
 
-	/* 11n or not? Pick the right rateset */
+	/* Pick the right rateset */
 	if (ieee80211_ht_check_tx_ht(ni)) {
 		/* XXX ew */
 		rs = (struct ieee80211_rateset *) &ni->ni_htrates;
@@ -426,6 +596,7 @@ amrr_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg __unused)
 		rs = &ni->ni_rates;
 	}
 
+	amrr = amn->amn_amrr;
 	if (is_enough(amn) && (ticks - amn->amn_ticks) > amrr->amrr_interval) {
 		rix = amrr_update(amrr, amn, ni);
 		if (rix != amn->amn_rix) {
diff --git a/sys/net80211/ieee80211_amrr.h b/sys/net80211/ieee80211_amrr.h
index 795cbf673e56..49d62953e625 100644
--- a/sys/net80211/ieee80211_amrr.h
+++ b/sys/net80211/ieee80211_amrr.h
@@ -49,6 +49,10 @@ struct ieee80211_amrr_node {
 	struct ieee80211_amrr *amn_amrr;/* backpointer */
 	int	amn_rix;		/* current rate index */
 	int	amn_ticks;		/* time of last update */
+	/* for VHT, since there's no VHT RIX right now */
+	int	amn_vht_mcs;
+	int	amn_vht_nss;
+
 	/* statistics */
 	u_int	amn_txcnt;
 	u_int	amn_success;