iwlwifi: HT performance improvement changes

During rate scaling, checking for 0 retry count before decrement
the count by 1, this can avoid the retry count to become 255 (0xff),
which will cause the rate to drop faster than what we expect during good
condition (receive 0 retry packet). also change the algorithm to make
the rate not drop faster than what we like.

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-rs.c b/drivers/net/wireless/iwlwifi/iwl-agn-rs.c
index a6f4c74..0929f31 100644 (file)
--- a/drivers/net/wireless/iwlwifi/iwl-agn-rs.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-rs.c
@@ -801,7 +801,10 @@ static void rs_tx_status(void *priv_r, struct ieee80211_supported_band *sband,
            !(info->flags & IEEE80211_TX_STAT_AMPDU))
                return;
 
-       retries = info->status.rates[0].count - 1;
+       if (info->flags & IEEE80211_TX_STAT_AMPDU)
+               retries = 0;
+       else
+               retries = info->status.rates[0].count - 1;
 
        if (retries > 15)
                retries = 15;
@@ -1897,7 +1900,7 @@ static void rs_rate_scale_perform(struct iwl_priv *priv,
                if (high != IWL_RATE_INVALID && sr >= IWL_RATE_INCREASE_TH)
                        scale_action = 1;
                else if (low != IWL_RATE_INVALID)
-                       scale_action = -1;
+                       scale_action = 0;
        }
 
        /* Both adjacent throughputs are measured, but neither one has better
@@ -1918,9 +1921,7 @@ static void rs_rate_scale_perform(struct iwl_priv *priv,
                                        sr >= IWL_RATE_INCREASE_TH) {
                                scale_action = 1;
                        } else {
-                               IWL_DEBUG_RATE(priv,
-                                   "decrease rate because of high tpt\n");
-                               scale_action = -1;
+                               scale_action = 0;
                        }
 
                /* Lower adjacent rate's throughput is measured */

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-rs.h b/drivers/net/wireless/iwlwifi/iwl-agn-rs.h
index 345806d..ab59acc 100644 (file)
--- a/drivers/net/wireless/iwlwifi/iwl-agn-rs.h
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-rs.h
@@ -231,7 +231,7 @@ enum {
 #define IWL_RS_GOOD_RATIO              12800   /* 100% */
 #define IWL_RATE_SCALE_SWITCH          10880   /*  85% */
 #define IWL_RATE_HIGH_TH               10880   /*  85% */
-#define IWL_RATE_INCREASE_TH            8960   /*  70% */
+#define IWL_RATE_INCREASE_TH           6400    /*  50% */
 #define IWL_RATE_DECREASE_TH           1920    /*  15% */
 
 /* possible actions when in legacy mode */