rc80211-pid: export tuning parameters through debugfs

This adds all the tunable parameters used by rc80211_pid to debugfs for easy
testing and tuning.

Signed-off-by: Mattias Nissler <mattias.nissler@gmx.de>
Signed-off-by: Stefano Brivio <stefano.brivio@polimi.it>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 110 insertions, 25 deletions

diff --git a/net/mac80211/rc80211_pid.h b/net/mac80211/rc80211_pid.h
index 5d0056c1513b..425eb708182a 100644
--- a/net/mac80211/rc80211_pid.h
+++ b/net/mac80211/rc80211_pid.h
@@ -119,6 +119,20 @@ struct rc_pid_events_file_info {
         unsigned int next_entry;
 };
 
+struct rc_pid_debugfs_entries {
+        struct dentry *dir;
+        struct dentry *target;
+        struct dentry *sampling_period;
+        struct dentry *coeff_p;
+        struct dentry *coeff_i;
+        struct dentry *coeff_d;
+        struct dentry *smoothing_shift;
+        struct dentry *sharpen_factor;
+        struct dentry *sharpen_duration;
+        struct dentry *norm_offset;
+        struct dentry *fast_start;
+};
+
 void rate_control_pid_event_tx_status(struct rc_pid_event_buffer *buf,
                                              struct ieee80211_tx_status *stat);
 
@@ -222,8 +236,8 @@ struct rc_pid_info {
         /* Exponential averaging shift. */
         unsigned int smoothing_shift;
 
-        /* Sharpening shift and duration. */
-        unsigned int sharpen_shift;
+        /* Sharpening factor and duration. */
+        unsigned int sharpen_factor;
         unsigned int sharpen_duration;
 
         /* Normalization offset. */
@@ -237,6 +251,11 @@ struct rc_pid_info {
 
         /* Index of the last used rate. */
         int oldrate;
+
+#ifdef CONFIG_MAC80211_DEBUGFS
+        /* Debugfs entries created for the parameters above. */
+        struct rc_pid_debugfs_entries dentries;
+#endif
 };
 
 #endif /* RC80211_PID_H */
diff --git a/net/mac80211/rc80211_pid_algo.c b/net/mac80211/rc80211_pid_algo.c
index 3fac3a5d7e00..631e46888267 100644
--- a/net/mac80211/rc80211_pid_algo.c
+++ b/net/mac80211/rc80211_pid_algo.c
@@ -139,19 +139,20 @@ static void rate_control_pid_adjust_rate(struct ieee80211_local *local,
 }
 
 /* Normalize the failed frames per-rate differences. */
-static void rate_control_pid_normalize(struct rc_pid_rateinfo *r, int l)
+static void rate_control_pid_normalize(struct rc_pid_info *pinfo, int l)
 {
-        int i;
+        int i, norm_offset = pinfo->norm_offset;
+        struct rc_pid_rateinfo *r = pinfo->rinfo;
 
-        if (r[0].diff > RC_PID_NORM_OFFSET)
-                r[0].diff -= RC_PID_NORM_OFFSET;
-        else if (r[0].diff < -RC_PID_NORM_OFFSET)
-                r[0].diff += RC_PID_NORM_OFFSET;
+        if (r[0].diff > norm_offset)
+                r[0].diff -= norm_offset;
+        else if (r[0].diff < -norm_offset)
+                r[0].diff += norm_offset;
         for (i = 0; i < l - 1; i++)
-                if (r[i + 1].diff > r[i].diff + RC_PID_NORM_OFFSET)
-                        r[i + 1].diff -= RC_PID_NORM_OFFSET;
+                if (r[i + 1].diff > r[i].diff + norm_offset)
+                        r[i + 1].diff -= norm_offset;
                 else if (r[i + 1].diff <= r[i].diff)
-                        r[i + 1].diff += RC_PID_NORM_OFFSET;
+                        r[i + 1].diff += norm_offset;
 }
 
 static void rate_control_pid_sample(struct rc_pid_info *pinfo,
@@ -163,18 +164,22 @@ static void rate_control_pid_sample(struct rc_pid_info *pinfo,
         struct ieee80211_hw_mode *mode;
         u32 pf;
         s32 err_avg;
-        s32 err_prop;
-        s32 err_int;
-        s32 err_der;
+        u32 err_prop;
+        u32 err_int;
+        u32 err_der;
         int adj, i, j, tmp;
+        unsigned long period;
 
         mode = local->oper_hw_mode;
         spinfo = sta->rate_ctrl_priv;
 
         /* In case nothing happened during the previous control interval, turn
          * the sharpening factor on. */
-        if (jiffies - spinfo->last_sample > 2 * RC_PID_INTERVAL)
-                spinfo->sharp_cnt = RC_PID_SHARPENING_DURATION;
+        period = (HZ * pinfo->sampling_period + 500) / 1000;
+        if (!period)
+                period = 1;
+        if (jiffies - spinfo->last_sample > 2 * period)
+                spinfo->sharp_cnt = pinfo->sharpen_duration;
 
         spinfo->last_sample = jiffies;
 
@@ -202,17 +207,17 @@ static void rate_control_pid_sample(struct rc_pid_info *pinfo,
                 rinfo[j].diff = rinfo[i].diff + tmp;
                 pinfo->oldrate = sta->txrate;
         }
-        rate_control_pid_normalize(rinfo, mode->num_rates);
+        rate_control_pid_normalize(pinfo, mode->num_rates);
 
         /* Compute the proportional, integral and derivative errors. */
-        err_prop = RC_PID_TARGET_PF - pf;
+        err_prop = pinfo->target - pf;
 
-        err_avg = spinfo->err_avg_sc >> RC_PID_SMOOTHING_SHIFT;
+        err_avg = spinfo->err_avg_sc >> pinfo->smoothing_shift;
         spinfo->err_avg_sc = spinfo->err_avg_sc - err_avg + err_prop;
-        err_int = spinfo->err_avg_sc >> RC_PID_SMOOTHING_SHIFT;
+        err_int = spinfo->err_avg_sc >> pinfo->smoothing_shift;
 
-        err_der = pf - spinfo->last_pf
-                  * (1 + RC_PID_SHARPENING_FACTOR * spinfo->sharp_cnt);
+        err_der = (pf - spinfo->last_pf) *
+                  (1 + pinfo->sharpen_factor * spinfo->sharp_cnt);
         spinfo->last_pf = pf;
         if (spinfo->sharp_cnt)
                         spinfo->sharp_cnt--;
@@ -241,6 +246,7 @@ static void rate_control_pid_tx_status(void *priv, struct net_device *dev,
         struct rc_pid_info *pinfo = priv;
         struct sta_info *sta;
         struct rc_pid_sta_info *spinfo;
+        unsigned long period;
 
         sta = sta_info_get(local, hdr->addr1);
 
@@ -285,7 +291,10 @@ static void rate_control_pid_tx_status(void *priv, struct net_device *dev,
         sta->tx_num_mpdu_fail += status->retry_count;
 
         /* Update PID controller state. */
-        if (time_after(jiffies, spinfo->last_sample + RC_PID_INTERVAL))
+        period = (HZ * pinfo->sampling_period + 500) / 1000;
+        if (!period)
+                period = 1;
+        if (time_after(jiffies, spinfo->last_sample + period))
                 rate_control_pid_sample(pinfo, local, sta);
 
         sta_info_put(sta);
@@ -343,6 +352,9 @@ static void *rate_control_pid_alloc(struct ieee80211_local *local)
         struct ieee80211_hw_mode *mode;
         int i, j, tmp;
         bool s;
+#ifdef CONFIG_MAC80211_DEBUGFS
+        struct rc_pid_debugfs_entries *de;
+#endif
 
         pinfo = kmalloc(sizeof(*pinfo), GFP_ATOMIC);
         if (!pinfo)
@@ -363,10 +375,10 @@ static void *rate_control_pid_alloc(struct ieee80211_local *local)
         for (i = 0; i < mode->num_rates; i++) {
                 rinfo[i].index = i;
                 rinfo[i].rev_index = i;
-                if (RC_PID_FAST_START)
+                if (pinfo->fast_start)
                         rinfo[i].diff = 0;
                 else
-                        rinfo[i].diff = i * RC_PID_NORM_OFFSET;
+                        rinfo[i].diff = i * pinfo->norm_offset;
         }
         for (i = 1; i < mode->num_rates; i++) {
                 s = 0;
@@ -385,18 +397,72 @@ static void *rate_control_pid_alloc(struct ieee80211_local *local)
         }
 
         pinfo->target = RC_PID_TARGET_PF;
+        pinfo->sampling_period = RC_PID_INTERVAL;
         pinfo->coeff_p = RC_PID_COEFF_P;
         pinfo->coeff_i = RC_PID_COEFF_I;
         pinfo->coeff_d = RC_PID_COEFF_D;
+        pinfo->smoothing_shift = RC_PID_SMOOTHING_SHIFT;
+        pinfo->sharpen_factor = RC_PID_SHARPENING_FACTOR;
+        pinfo->sharpen_duration = RC_PID_SHARPENING_DURATION;
+        pinfo->norm_offset = RC_PID_NORM_OFFSET;
+        pinfo->fast_start = RC_PID_FAST_START;
         pinfo->rinfo = rinfo;
         pinfo->oldrate = 0;
 
+#ifdef CONFIG_MAC80211_DEBUGFS
+        de = &pinfo->dentries;
+        de->dir = debugfs_create_dir("rc80211_pid",
+                                     local->hw.wiphy->debugfsdir);
+        de->target = debugfs_create_u32("target_pf", S_IRUSR | S_IWUSR,
+                                        de->dir, &pinfo->target);
+        de->sampling_period = debugfs_create_u32("sampling_period",
+                                                 S_IRUSR | S_IWUSR, de->dir,
+                                                 &pinfo->sampling_period);
+        de->coeff_p = debugfs_create_u32("coeff_p", S_IRUSR | S_IWUSR,
+                                         de->dir, &pinfo->coeff_p);
+        de->coeff_i = debugfs_create_u32("coeff_i", S_IRUSR | S_IWUSR,
+                                         de->dir, &pinfo->coeff_i);
+        de->coeff_d = debugfs_create_u32("coeff_d", S_IRUSR | S_IWUSR,
+                                         de->dir, &pinfo->coeff_d);
+        de->smoothing_shift = debugfs_create_u32("smoothing_shift",
+                                                 S_IRUSR | S_IWUSR, de->dir,
+                                                 &pinfo->smoothing_shift);
+        de->sharpen_factor = debugfs_create_u32("sharpen_factor",
+                                               S_IRUSR | S_IWUSR, de->dir,
+                                               &pinfo->sharpen_factor);
+        de->sharpen_duration = debugfs_create_u32("sharpen_duration",
+                                                  S_IRUSR | S_IWUSR, de->dir,
+                                                  &pinfo->sharpen_duration);
+        de->norm_offset = debugfs_create_u32("norm_offset",
+                                             S_IRUSR | S_IWUSR, de->dir,
+                                             &pinfo->norm_offset);
+        de->fast_start = debugfs_create_bool("fast_start",
+                                             S_IRUSR | S_IWUSR, de->dir,
+                                             &pinfo->fast_start);
+#endif
+
         return pinfo;
 }
 
 static void rate_control_pid_free(void *priv)
 {
         struct rc_pid_info *pinfo = priv;
+#ifdef CONFIG_MAC80211_DEBUGFS
+        struct rc_pid_debugfs_entries *de = &pinfo->dentries;
+
+        debugfs_remove(de->fast_start);
+        debugfs_remove(de->norm_offset);
+        debugfs_remove(de->sharpen_duration);
+        debugfs_remove(de->sharpen_factor);
+        debugfs_remove(de->smoothing_shift);
+        debugfs_remove(de->coeff_d);
+        debugfs_remove(de->coeff_i);
+        debugfs_remove(de->coeff_p);
+        debugfs_remove(de->sampling_period);
+        debugfs_remove(de->target);
+        debugfs_remove(de->dir);
+#endif
+
         kfree(pinfo->rinfo);
         kfree(pinfo);
 }