[PATCH 18/21] ath9k: Remove dead code in rate control

Luis R. Rodriguez
2009-07-15T00:14:25Z

From: Vasanthakumar Thiagarajan <vasanth@atheros.com>

ath9k rate control is based on only PER (packet error rate),
remove unused code which was intented to do rssi based rate
selection.

Signed-off-by: Vasanthakumar Thiagarajan <vasanth@atheros.com>
---
drivers/net/wireless/ath/ath9k/rc.c | 163 +----------------------------------
1 files changed, 4 insertions(+), 159 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/rc.c b/drivers/net/wireless/ath/ath9k/rc.c
index e66734c..a39b1a7 100644
--- a/drivers/net/wireless/ath/ath9k/rc.c
+++ b/drivers/net/wireless/ath/ath9k/rc.c
@@ -607,47 +607,14 @@ static u8 ath_rc_get_highest_rix(struct ath_softc *sc,
const struct ath_rate_table *rate_table,
int *is_probing)
{
- u32 dt, best_thruput, this_thruput, now_msec;
+ u32 best_thruput, this_thruput, now_msec;
u8 rate, next_rate, best_rate, maxindex, minindex;
- int8_t rssi_last, rssi_reduce = 0, index = 0;
-
- *is_probing = 0;
-
- rssi_last = median(ath_rc_priv->rssi_last,
- ath_rc_priv->rssi_last_prev,
- ath_rc_priv->rssi_last_prev2);
-
- /*
- * Age (reduce) last ack rssi based on how old it is.
- * The bizarre numbers are so the delta is 160msec,
- * meaning we divide by 16.
- * 0msec <= dt <= 25msec: don't derate
- * 25msec <= dt <= 185msec: derate linearly from 0 to 10dB
- * 185msec <= dt: derate by 10dB
- */
+ int8_t index = 0;

now_msec = jiffies_to_msecs(jiffies);
- dt = now_msec - ath_rc_priv->rssi_time;
-
- if (dt >= 185)
- rssi_reduce = 10;
- else if (dt >= 25)
- rssi_reduce = (u8)((dt - 25) >> 4);
-
- /* Now reduce rssi_last by rssi_reduce */
- if (rssi_last < rssi_reduce)
- rssi_last = 0;
- else
- rssi_last -= rssi_reduce;
-
- /*
- * Now look up the rate in the rssi table and return it.
- * If no rates match then we return 0 (lowest rate)
- */
-
+ *is_probing = 0;
best_thruput = 0;
maxindex = ath_rc_priv->max_valid_rate-1;
-
minindex = 0;
best_rate = minindex;

@@ -687,7 +654,6 @@ static u8 ath_rc_get_highest_rix(struct ath_softc *sc,
}

rate = best_rate;
- ath_rc_priv->rssi_last_lookup = rssi_last;

/*
* Must check the actual rate (ratekbps) to account for
@@ -977,10 +943,6 @@ static bool ath_rc_update_per(struct ath_softc *sc,
(nretry_to_per_lookup[retries] >> 3));
}

- ath_rc_priv->rssi_last_prev2 = ath_rc_priv->rssi_last_prev;
- ath_rc_priv->rssi_last_prev = ath_rc_priv->rssi_last;
- ath_rc_priv->rssi_last = tx_info_priv->tx.ts_rssi;
- ath_rc_priv->rssi_time = now_msec;

/*
* If we got at most one retry then increase the max rate if
@@ -1024,18 +986,9 @@ static bool ath_rc_update_per(struct ath_softc *sc,
/*
* Don't update anything. We don't know if
* this was because of collisions or poor signal.
- *
- * Later: if rssi_ack is close to
- * ath_rc_priv->state[txRate].rssi_thres and we see lots
- * of retries, then we could increase
- * ath_rc_priv->state[txRate].rssi_thres.
*/
ath_rc_priv->hw_maxretry_pktcnt = 0;
} else {
- int32_t rssi_ackAvg;
- int8_t rssi_thres;
- int8_t rssi_ack_vmin;
-
/*
* It worked with no retries. First ignore bogus (small)
* rssi_ack values.
@@ -1045,43 +998,9 @@ static bool ath_rc_update_per(struct ath_softc *sc,
ath_rc_priv->hw_maxretry_pktcnt++;
}

- if (tx_info_priv->tx.ts_rssi <
- rate_table->info[tx_rate].rssi_ack_validmin)
- goto exit;
-
- /* Average the rssi */
- if (tx_rate != ath_rc_priv->rssi_sum_rate) {
- ath_rc_priv->rssi_sum_rate = tx_rate;
- ath_rc_priv->rssi_sum =
- ath_rc_priv->rssi_sum_cnt = 0;
- }
-
- ath_rc_priv->rssi_sum += tx_info_priv->tx.ts_rssi;
- ath_rc_priv->rssi_sum_cnt++;
-
- if (ath_rc_priv->rssi_sum_cnt < 4)
- goto exit;
-
- rssi_ackAvg =
- (ath_rc_priv->rssi_sum + 2) / 4;
- rssi_thres =
- ath_rc_priv->state[tx_rate].rssi_thres;
- rssi_ack_vmin =
- rate_table->info[tx_rate].rssi_ack_validmin;
-
- ath_rc_priv->rssi_sum =
- ath_rc_priv->rssi_sum_cnt = 0;
-
- /* Now reduce the current rssi threshold */
- if ((rssi_ackAvg < rssi_thres + 2) &&
- (rssi_thres > rssi_ack_vmin)) {
- ath_rc_priv->state[tx_rate].rssi_thres--;
- }
-
- state_change = true;
}
}
-exit:
+
return state_change;
}

@@ -1093,11 +1012,6 @@ static void ath_rc_update_ht(struct ath_softc *sc,
struct ath_tx_info_priv *tx_info_priv,
int tx_rate, int xretries, int retries)
{
-#define CHK_RSSI(rate) \
- ((ath_rc_priv->state[(rate)].rssi_thres + \
- rate_table->info[(rate)].rssi_ack_deltamin) > \
- ath_rc_priv->state[(rate)+1].rssi_thres)
-
u32 now_msec = jiffies_to_msecs(jiffies);
int rate;
u8 last_per;
@@ -1108,13 +1022,6 @@ static void ath_rc_update_ht(struct ath_softc *sc,
if ((tx_rate < 0) || (tx_rate > rate_table->rate_cnt))
return;

- /* To compensate for some imbalance between ctrl and ext. channel */
-
- if (WLAN_RC_PHY_40(rate_table->info[tx_rate].phy))
- tx_info_priv->tx.ts_rssi =
- tx_info_priv->tx.ts_rssi < 3 ? 0 :
- tx_info_priv->tx.ts_rssi - 3;
-
last_per = ath_rc_priv->state[tx_rate].per;

/* Update PER first */
@@ -1136,51 +1043,6 @@ static void ath_rc_update_ht(struct ath_softc *sc,
ath_rc_priv->probe_time = now_msec;
}

- if (state_change) {
- /*
- * Make sure the rates above this have higher rssi thresholds.
- * (Note: Monotonicity is kept within the OFDM rates and
- * within the CCK rates. However, no adjustment is
- * made to keep the rssi thresholds monotonically
- * increasing between the CCK and OFDM rates.)
- */
- for (rate = tx_rate; rate < size - 1; rate++) {
- if (rate_table->info[rate+1].phy !=
- rate_table->info[tx_rate].phy)
- break;
-
- if (CHK_RSSI(rate)) {
- ath_rc_priv->state[rate+1].rssi_thres =
- ath_rc_priv->state[rate].rssi_thres +
- rate_table->info[rate].rssi_ack_deltamin;
- }
- }
-
- /* Make sure the rates below this have lower rssi thresholds. */
- for (rate = tx_rate - 1; rate >= 0; rate--) {
- if (rate_table->info[rate].phy !=
- rate_table->info[tx_rate].phy)
- break;
-
- if (CHK_RSSI(rate)) {
- if (ath_rc_priv->state[rate+1].rssi_thres <
- rate_table->info[rate].rssi_ack_deltamin)
- ath_rc_priv->state[rate].rssi_thres = 0;
- else {
- ath_rc_priv->state[rate].rssi_thres =
- ath_rc_priv->state[rate+1].rssi_thres -
- rate_table->info[rate].rssi_ack_deltamin;
- }
-
- if (ath_rc_priv->state[rate].rssi_thres <
- rate_table->info[rate].rssi_ack_validmin) {
- ath_rc_priv->state[rate].rssi_thres =
- rate_table->info[rate].rssi_ack_validmin;
- }
- }
- }
- }
-
/* Make sure the rates below this have lower PER */
/* Monotonicity is kept only for rates below the current rate. */
if (ath_rc_priv->state[tx_rate].per < last_per) {
@@ -1205,19 +1067,6 @@ static void ath_rc_update_ht(struct ath_softc *sc,
ath_rc_priv->state[rate].per;
}

- /* Every so often, we reduce the thresholds and
- * PER (different for CCK and OFDM). */
- if (now_msec - ath_rc_priv->rssi_down_time >=
- rate_table->rssi_reduce_interval) {
-
- for (rate = 0; rate < size; rate++) {
- if (ath_rc_priv->state[rate].rssi_thres >
- rate_table->info[rate].rssi_ack_validmin)
- ath_rc_priv->state[rate].rssi_thres -= 1;
- }
- ath_rc_priv->rssi_down_time = now_msec;
- }
-
/* Every so often, we reduce the thresholds
* and PER (different for CCK and OFDM). */
if (now_msec - ath_rc_priv->per_down_time >=
@@ -1233,7 +1082,6 @@ static void ath_rc_update_ht(struct ath_softc *sc,
ath_debug_stat_retries(sc, tx_rate, xretries, retries,
ath_rc_priv->state[tx_rate].per);

-#undef CHK_RSSI
}

static int ath_rc_get_rateindex(const struct ath_rate_table *rate_table,
@@ -1369,8 +1217,6 @@ static void ath_rc_init(struct ath_softc *sc,

/* Initialize thresholds according to the global rate table */
for (i = 0 ; i < ath_rc_priv->rate_table_size; i++) {
- ath_rc_priv->state[i].rssi_thres =
- rate_table->info[i].rssi_ack_validmin;
ath_rc_priv->state[i].per = 0;
}

@@ -1631,7 +1477,6 @@ static void *ath_rate_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp
return NULL;
}

- rate_priv->rssi_down_time = jiffies_to_msecs(jiffies);
rate_priv->tx_triglevel_max = sc->sc_ah->caps.tx_triglevel_max;

return rate_priv;
--
1.6.0.6