fishHEADmaster

1 files changed, 278 insertions, 0 deletions

diff --git a/net/mac80211/rc80211_pid.h b/net/mac80211/rc80211_pid.h
new file mode 100644
index 0000000..a254ebe
--- /dev/null
+++ b/net/mac80211/rc80211_pid.h
@@ -0,0 +1,278 @@
+/*
+ * Copyright 2007, Mattias Nissler <mattias.nissler@gmx.de>
+ * Copyright 2007, Stefano Brivio <stefano.brivio@polimi.it>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef RC80211_PID_H
+#define RC80211_PID_H
+
+/* Sampling period for measuring percentage of failed frames in ms. */
+#define RC_PID_INTERVAL			125
+
+/* Exponential averaging smoothness (used for I part of PID controller) */
+#define RC_PID_SMOOTHING_SHIFT		3
+#define RC_PID_SMOOTHING		(1 << RC_PID_SMOOTHING_SHIFT)
+
+/* Sharpening factor (used for D part of PID controller) */
+#define RC_PID_SHARPENING_FACTOR	0
+#define RC_PID_SHARPENING_DURATION	0
+
+/* Fixed point arithmetic shifting amount. */
+#define RC_PID_ARITH_SHIFT		8
+
+/* Proportional PID component coefficient. */
+#define RC_PID_COEFF_P			15
+/* Integral PID component coefficient. */
+#define RC_PID_COEFF_I			9
+/* Derivative PID component coefficient. */
+#define RC_PID_COEFF_D			15
+
+/* Target failed frames rate for the PID controller. NB: This effectively gives
+ * maximum failed frames percentage we're willing to accept. If the wireless
+ * link quality is good, the controller will fail to adjust failed frames
+ * percentage to the target. This is intentional.
+ */
+#define RC_PID_TARGET_PF		14
+
+/* Rate behaviour normalization quantity over time. */
+#define RC_PID_NORM_OFFSET		3
+
+/* Push high rates right after loading. */
+#define RC_PID_FAST_START		0
+
+/* Arithmetic right shift for positive and negative values for ISO C. */
+#define RC_PID_DO_ARITH_RIGHT_SHIFT(x, y) \
+	((x) < 0 ? -((-(x)) >> (y)) : (x) >> (y))
+
+enum rc_pid_event_type {
+	RC_PID_EVENT_TYPE_TX_STATUS,
+	RC_PID_EVENT_TYPE_RATE_CHANGE,
+	RC_PID_EVENT_TYPE_TX_RATE,
+	RC_PID_EVENT_TYPE_PF_SAMPLE,
+};
+
+union rc_pid_event_data {
+	/* RC_PID_EVENT_TX_STATUS */
+	struct {
+		u32 flags;
+		struct ieee80211_tx_info tx_status;
+	};
+	/* RC_PID_EVENT_TYPE_RATE_CHANGE */
+	/* RC_PID_EVENT_TYPE_TX_RATE */
+	struct {
+		int index;
+		int rate;
+	};
+	/* RC_PID_EVENT_TYPE_PF_SAMPLE */
+	struct {
+		s32 pf_sample;
+		s32 prop_err;
+		s32 int_err;
+		s32 der_err;
+	};
+};
+
+struct rc_pid_event {
+	/* The time when the event occurred */
+	unsigned long timestamp;
+
+	/* Event ID number */
+	unsigned int id;
+
+	/* Type of event */
+	enum rc_pid_event_type type;
+
+	/* type specific data */
+	union rc_pid_event_data data;
+};
+
+/* Size of the event ring buffer. */
+#define RC_PID_EVENT_RING_SIZE 32
+
+struct rc_pid_event_buffer {
+	/* Counter that generates event IDs */
+	unsigned int ev_count;
+
+	/* Ring buffer of events */
+	struct rc_pid_event ring[RC_PID_EVENT_RING_SIZE];
+
+	/* Index to the entry in events_buf to be reused */
+	unsigned int next_entry;
+
+	/* Lock that guards against concurrent access to this buffer struct */
+	spinlock_t lock;
+
+	/* Wait queue for poll/select and blocking I/O */
+	wait_queue_head_t waitqueue;
+};
+
+struct rc_pid_events_file_info {
+	/* The event buffer we read */
+	struct rc_pid_event_buffer *events;
+
+	/* The entry we have should read next */
+	unsigned int next_entry;
+};
+
+/**
+ * struct rc_pid_debugfs_entries - tunable parameters
+ *
+ * Algorithm parameters, tunable via debugfs.
+ * @target: target percentage for failed frames
+ * @sampling_period: error sampling interval in milliseconds
+ * @coeff_p: absolute value of the proportional coefficient
+ * @coeff_i: absolute value of the integral coefficient
+ * @coeff_d: absolute value of the derivative coefficient
+ * @smoothing_shift: absolute value of the integral smoothing factor (i.e.
+ *	amount of smoothing introduced by the exponential moving average)
+ * @sharpen_factor: absolute value of the derivative sharpening factor (i.e.
+ *	amount of emphasis given to the derivative term after low activity
+ *	events)
+ * @sharpen_duration: duration of the sharpening effect after the detected low
+ *	activity event, relative to sampling_period
+ * @norm_offset: amount of normalization periodically performed on the learnt
+ *	rate behaviour values (lower means we should trust more what we learnt
+ *	about behaviour of rates, higher means we should trust more the natural
+ *	ordering of rates)
+ */
+struct rc_pid_debugfs_entries {
+	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;
+};
+
+void rate_control_pid_event_tx_status(struct rc_pid_event_buffer *buf,
+				      struct ieee80211_tx_info *stat);
+
+void rate_control_pid_event_rate_change(struct rc_pid_event_buffer *buf,
+					       int index, int rate);
+
+void rate_control_pid_event_tx_rate(struct rc_pid_event_buffer *buf,
+					   int index, int rate);
+
+void rate_control_pid_event_pf_sample(struct rc_pid_event_buffer *buf,
+					     s32 pf_sample, s32 prop_err,
+					     s32 int_err, s32 der_err);
+
+void rate_control_pid_add_sta_debugfs(void *priv, void *priv_sta,
+					     struct dentry *dir);
+
+void rate_control_pid_remove_sta_debugfs(void *priv, void *priv_sta);
+
+struct rc_pid_sta_info {
+	unsigned long last_change;
+	unsigned long last_sample;
+
+	u32 tx_num_failed;
+	u32 tx_num_xmit;
+
+	int txrate_idx;
+
+	/* Average failed frames percentage error (i.e. actual vs. target
+	 * percentage), scaled by RC_PID_SMOOTHING. This value is computed
+	 * using using an exponential weighted average technique:
+	 *
+	 *           (RC_PID_SMOOTHING - 1) * err_avg_old + err
+	 * err_avg = ------------------------------------------
+	 *                       RC_PID_SMOOTHING
+	 *
+	 * where err_avg is the new approximation, err_avg_old the previous one
+	 * and err is the error w.r.t. to the current failed frames percentage
+	 * sample. Note that the bigger RC_PID_SMOOTHING the more weight is
+	 * given to the previous estimate, resulting in smoother behavior (i.e.
+	 * corresponding to a longer integration window).
+	 *
+	 * For computation, we actually don't use the above formula, but this
+	 * one:
+	 *
+	 * err_avg_scaled = err_avg_old_scaled - err_avg_old + err
+	 *
+	 * where:
+	 * 	err_avg_scaled = err * RC_PID_SMOOTHING
+	 * 	err_avg_old_scaled = err_avg_old * RC_PID_SMOOTHING
+	 *
+	 * This avoids floating point numbers and the per_failed_old value can
+	 * easily be obtained by shifting per_failed_old_scaled right by
+	 * RC_PID_SMOOTHING_SHIFT.
+	 */
+	s32 err_avg_sc;
+
+	/* Last framed failes percentage sample. */
+	u32 last_pf;
+
+	/* Sharpening needed. */
+	u8 sharp_cnt;
+
+#ifdef CPTCFG_MAC80211_DEBUGFS
+	/* Event buffer */
+	struct rc_pid_event_buffer events;
+
+	/* Events debugfs file entry */
+	struct dentry *events_entry;
+#endif
+};
+
+/* Algorithm parameters. We keep them on a per-algorithm approach, so they can
+ * be tuned individually for each interface.
+ */
+struct rc_pid_rateinfo {
+
+	/* Map sorted rates to rates in ieee80211_hw_mode. */
+	int index;
+
+	/* Map rates in ieee80211_hw_mode to sorted rates. */
+	int rev_index;
+
+	/* Did we do any measurement on this rate? */
+	bool valid;
+
+	/* Comparison with the lowest rate. */
+	int diff;
+};
+
+struct rc_pid_info {
+
+	/* The failed frames percentage target. */
+	unsigned int target;
+
+	/* Rate at which failed frames percentage is sampled in 0.001s. */
+	unsigned int sampling_period;
+
+	/* P, I and D coefficients. */
+	int coeff_p;
+	int coeff_i;
+	int coeff_d;
+
+	/* Exponential averaging shift. */
+	unsigned int smoothing_shift;
+
+	/* Sharpening factor and duration. */
+	unsigned int sharpen_factor;
+	unsigned int sharpen_duration;
+
+	/* Normalization offset. */
+	unsigned int norm_offset;
+
+	/* Rates information. */
+	struct rc_pid_rateinfo *rinfo;
+
+	/* Index of the last used rate. */
+	int oldrate;
+
+#ifdef CPTCFG_MAC80211_DEBUGFS
+	/* Debugfs entries created for the parameters above. */
+	struct rc_pid_debugfs_entries dentries;
+#endif
+};
+
+#endif /* RC80211_PID_H */