SampleRate rate control algorithm for the ath driver

Submitted by:	John Bicket

1 files changed, 136 insertions, 0 deletions

diff --git a/sys/dev/ath/ath_rate/sample/sample.h b/sys/dev/ath/ath_rate/sample/sample.h
new file mode 100644
index 0000000..3c6c5e4
--- /dev/null
+++ b/sys/dev/ath/ath_rate/sample/sample.h
@@ -0,0 +1,136 @@
+/*-
+ * Copyright (c) 2005 John Bicket
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer,
+ *    without modification.
+ * 2. Redistributions in binary form must reproduce at minimum a disclaimer
+ *    similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
+ *    redistribution must be conditioned upon including a substantially
+ *    similar Disclaimer requirement for further binary redistribution.
+ * 3. Neither the names of the above-listed copyright holders nor the names
+ *    of any contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * NO WARRANTY
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
+ * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
+ * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
+ * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGES.
+ *
+ * $FreeBSD$
+ */
+
+/*
+ * Defintions for the Atheros Wireless LAN controller driver.
+ */
+#ifndef _DEV_ATH_RATE_SAMPLE_H
+#define _DEV_ATH_RATE_SAMPLE_H
+
+/* per-device state */
+struct sample_softc {
+	struct ath_ratectrl arc;	/* base state */
+	int	ath_smoothing_rate;	/* ewma percentage (out of 100) */
+	int	ath_sample_rate;	/* send a different bit-rate 1/X packets */
+};
+#define	ATH_SOFTC_SAMPLE(sc)	((struct sample_softc *)sc->sc_rc)
+
+struct rate_info {
+	int rate;
+	int rix;
+	int rateCode;
+	int shortPreambleRateCode;
+};
+
+
+struct rate_stats {	
+	int average_tx_time;
+	int successive_failures;
+	int tries;
+	int total_packets;
+	int packets_acked;
+	int perfect_tx_time; /* transmit time for 0 retries */
+	int last_tx;
+};
+
+/*
+ * for now, we track performance for three different packet
+ * size buckets
+ */
+#define NUM_PACKET_SIZE_BINS 3
+static int packet_size_bins[NUM_PACKET_SIZE_BINS] = {250, 1600, 3000};
+
+/* per-node state */
+struct sample_node {
+	int static_rate_ndx;
+	int num_rates;
+
+	struct rate_info rates[IEEE80211_RATE_MAXSIZE];
+	
+	struct rate_stats stats[NUM_PACKET_SIZE_BINS][IEEE80211_RATE_MAXSIZE];
+	int sample_num[NUM_PACKET_SIZE_BINS];       
+	int packets_sent[NUM_PACKET_SIZE_BINS];
+
+};
+#define	ATH_NODE_SAMPLE(an)	((struct sample_node *)&an[1])
+
+#ifndef MIN
+#define	MIN(a,b)	((a) < (b) ? (a) : (b))
+#endif
+#ifndef MAX
+#define	MAX(a,b)	((a) > (b) ? (a) : (b))
+#endif
+
+#define WIFI_CW_MIN 31
+#define WIFI_CW_MAX 1023
+
+/*
+ * Calculate the transmit duration of a frame.
+ */
+static unsigned calc_usecs_unicast_packet(struct ath_softc *sc,
+				int length, 
+				int rix, int retries) {
+	const HAL_RATE_TABLE *rt = sc->sc_currates;
+
+	
+	/* pg 205 ieee.802.11.pdf */
+	unsigned t_slot = 20;
+	unsigned t_difs = 50; 
+	unsigned t_sifs = 10; 
+	int tt = 0;
+	int x = 0;
+	int cw = WIFI_CW_MIN;
+	int cix = rt->info[rix].controlRate;
+	KASSERT(rt != NULL, ("no rate table, mode %u", sc->sc_curmode));
+	
+	if (rt->info[rix].phy == IEEE80211_T_OFDM) {
+		t_slot = 9;
+		t_sifs = 9;
+		t_difs = 28;
+	}
+	tt += t_difs;
+	tt += (retries+1)*(t_sifs + rt->info[cix].spAckDuration);
+	tt += (retries+1)*ath_hal_computetxtime(sc->sc_ah, rt, length, 
+						rix, AH_TRUE);
+	for (x = 0; x <= retries; x++) {
+		cw = MIN(WIFI_CW_MAX, (cw + 1) * 2);
+		tt += (t_slot * cw/2);
+	}
+	return tt;
+}
+#endif /* _DEV_ATH_RATE_SAMPLE_H */