openwrt/package/kernel/mac80211/patches/555-ath9k-dynack-make-ewma-estimation-faster.patch
Koen Vandeputte 779b89c757 ath9k: fix dynack in IBSS mode
Currently, dynack was only tested upstream using AP/STA mode.
Testing it on IBSS, showed that late-ack detection was broken.

This is caused due to dynack using Association Request/Response
frames for late-ack detection, which IBSS does not use.
Also allowing Authentication frames here solves this.

A second issue also got fixed, which was also seen AP/STA mode:

When a station was added, the estimated value would be exponentially averaged
using 0 as a starting point.

This means that on larger distances, the ack timeout was still not high
enough before synchronizing would run out of late-ack's for estimation.

Fix this by using the initial estimated value as a baseline
and only start averaging in the following estimation rounds.

Test setup:
- 2x identical devices:  RB912UAG-5HPnD + 19dB sector
- IBSS
- 2x2 802.11an (ar9340), HT20, long GI
- RSSI's  -70 / -71
- Real distance: 23910 meter

Results (60s iperf runs):

Fixed coverage class 54 (up to 24300m):
* 21.5 Mbits/sec

Dynack:
* 28.9 Mbits/sec

Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
2018-11-06 11:49:55 +01:00

140 lines
4.4 KiB
Diff

From: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Date: Fri, 2 Nov 2018 21:49:58 +0100
Subject: [PATCH] ath9k: dynack: make ewma estimation faster
In order to make propagation time estimation faster,
use current sample as ewma output value during 'late ack'
tracking
Tested-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
---
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -273,7 +273,7 @@ struct ath_node {
#endif
u8 key_idx[4];
- u32 ackto;
+ int ackto;
struct list_head list;
};
--- a/drivers/net/wireless/ath/ath9k/dynack.c
+++ b/drivers/net/wireless/ath/ath9k/dynack.c
@@ -29,9 +29,13 @@
* ath_dynack_ewma - EWMA (Exponentially Weighted Moving Average) calculation
*
*/
-static inline u32 ath_dynack_ewma(u32 old, u32 new)
+static inline int ath_dynack_ewma(int old, int new)
{
- return (new * (EWMA_DIV - EWMA_LEVEL) + old * EWMA_LEVEL) / EWMA_DIV;
+ if (old > 0)
+ return (new * (EWMA_DIV - EWMA_LEVEL) +
+ old * EWMA_LEVEL) / EWMA_DIV;
+ else
+ return new;
}
/**
@@ -82,10 +86,10 @@ static inline bool ath_dynack_bssidmask(
*/
static void ath_dynack_compute_ackto(struct ath_hw *ah)
{
- struct ath_node *an;
- u32 to = 0;
- struct ath_dynack *da = &ah->dynack;
struct ath_common *common = ath9k_hw_common(ah);
+ struct ath_dynack *da = &ah->dynack;
+ struct ath_node *an;
+ int to = 0;
list_for_each_entry(an, &da->nodes, list)
if (an->ackto > to)
@@ -144,7 +148,8 @@ static void ath_dynack_compute_to(struct
an->ackto = ath_dynack_ewma(an->ackto,
ackto);
ath_dbg(ath9k_hw_common(ah), DYNACK,
- "%pM to %u\n", dst, an->ackto);
+ "%pM to %d [%u]\n", dst,
+ an->ackto, ackto);
if (time_is_before_jiffies(da->lto)) {
ath_dynack_compute_ackto(ah);
da->lto = jiffies + COMPUTE_TO;
@@ -166,10 +171,12 @@ static void ath_dynack_compute_to(struct
* @ah: ath hw
* @skb: socket buffer
* @ts: tx status info
+ * @sta: station pointer
*
*/
void ath_dynack_sample_tx_ts(struct ath_hw *ah, struct sk_buff *skb,
- struct ath_tx_status *ts)
+ struct ath_tx_status *ts,
+ struct ieee80211_sta *sta)
{
struct ieee80211_hdr *hdr;
struct ath_dynack *da = &ah->dynack;
@@ -191,9 +198,16 @@ void ath_dynack_sample_tx_ts(struct ath_
ieee80211_is_assoc_resp(hdr->frame_control) ||
ieee80211_is_auth(hdr->frame_control)) {
ath_dbg(common, DYNACK, "late ack\n");
+
ath9k_hw_setslottime(ah, (LATEACK_TO - 3) / 2);
ath9k_hw_set_ack_timeout(ah, LATEACK_TO);
ath9k_hw_set_cts_timeout(ah, LATEACK_TO);
+ if (sta) {
+ struct ath_node *an;
+
+ an = (struct ath_node *)sta->drv_priv;
+ an->ackto = -1;
+ }
da->lto = jiffies + LATEACK_DELAY;
}
--- a/drivers/net/wireless/ath/ath9k/dynack.h
+++ b/drivers/net/wireless/ath/ath9k/dynack.h
@@ -86,7 +86,8 @@ void ath_dynack_node_deinit(struct ath_h
void ath_dynack_init(struct ath_hw *ah);
void ath_dynack_sample_ack_ts(struct ath_hw *ah, struct sk_buff *skb, u32 ts);
void ath_dynack_sample_tx_ts(struct ath_hw *ah, struct sk_buff *skb,
- struct ath_tx_status *ts);
+ struct ath_tx_status *ts,
+ struct ieee80211_sta *sta);
#else
static inline void ath_dynack_init(struct ath_hw *ah) {}
static inline void ath_dynack_node_init(struct ath_hw *ah,
@@ -97,7 +98,8 @@ static inline void ath_dynack_sample_ack
struct sk_buff *skb, u32 ts) {}
static inline void ath_dynack_sample_tx_ts(struct ath_hw *ah,
struct sk_buff *skb,
- struct ath_tx_status *ts) {}
+ struct ath_tx_status *ts,
+ struct ieee80211_sta *sta) {}
#endif
#endif /* DYNACK_H */
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -629,7 +629,7 @@ static void ath_tx_complete_aggr(struct
if (bf == bf->bf_lastbf)
ath_dynack_sample_tx_ts(sc->sc_ah,
bf->bf_mpdu,
- ts);
+ ts, sta);
}
ath_tx_complete_buf(sc, bf, txq, &bf_head, sta, ts,
@@ -773,7 +773,8 @@ static void ath_tx_process_buffer(struct
memcpy(info->control.rates, bf->rates,
sizeof(info->control.rates));
ath_tx_rc_status(sc, bf, ts, 1, txok ? 0 : 1, txok);
- ath_dynack_sample_tx_ts(sc->sc_ah, bf->bf_mpdu, ts);
+ ath_dynack_sample_tx_ts(sc->sc_ah, bf->bf_mpdu, ts,
+ sta);
}
ath_tx_complete_buf(sc, bf, txq, bf_head, sta, ts, txok);
} else