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Diffstat (limited to 'sys/dev/ath/ath_rate/sample/sample.c')
-rw-r--r-- | sys/dev/ath/ath_rate/sample/sample.c | 608 |
1 files changed, 608 insertions, 0 deletions
diff --git a/sys/dev/ath/ath_rate/sample/sample.c b/sys/dev/ath/ath_rate/sample/sample.c new file mode 100644 index 0000000..3bcec99 --- /dev/null +++ b/sys/dev/ath/ath_rate/sample/sample.c @@ -0,0 +1,608 @@ +/*- + * 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. + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +/* + * John Bicket's SampleRate control algorithm. + */ +#include "opt_inet.h" + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/sysctl.h> +#include <sys/module.h> +#include <sys/kernel.h> +#include <sys/lock.h> +#include <sys/mutex.h> +#include <sys/errno.h> + +#include <machine/bus.h> +#include <machine/resource.h> +#include <sys/bus.h> + +#include <sys/socket.h> + +#include <net/if.h> +#include <net/if_media.h> +#include <net/if_arp.h> +#include <net/ethernet.h> /* XXX for ether_sprintf */ + +#include <net80211/ieee80211_var.h> + +#include <net/bpf.h> + +#ifdef INET +#include <netinet/in.h> +#include <netinet/if_ether.h> +#endif + +#include <dev/ath/if_athvar.h> +#include <dev/ath/ath_rate/sample/sample.h> +#include <contrib/dev/ath/ah_desc.h> + +#define SAMPLE_DEBUG +#ifdef SAMPLE_DEBUG +enum { + ATH_DEBUG_RATE = 0x00000010, /* rate control */ +}; +#define DPRINTF(sc, _fmt, ...) do { \ + if (sc->sc_debug & ATH_DEBUG_RATE) \ + printf(_fmt, __VA_ARGS__); \ +} while (0) +#else +#define DPRINTF(sc, _fmt, ...) +#endif + +/* + * This file is an implementation of the SampleRate algorithm + * in "Bit-rate Selection in Wireless Networks" + * (http://www.pdos.lcs.mit.edu/papers/jbicket-ms.ps) + * + * SampleRate chooses the bit-rate it predicts will provide the most + * throughput based on estimates of the expected per-packet + * transmission time for each bit-rate. SampleRate periodically sends + * packets at bit-rates other than the current one to estimate when + * another bit-rate will provide better performance. SampleRate + * switches to another bit-rate when its estimated per-packet + * transmission time becomes smaller than the current bit-rate's. + * SampleRate reduces the number of bit-rates it must sample by + * eliminating those that could not perform better than the one + * currently being used. SampleRate also stops probing at a bit-rate + * if it experiences several successive losses. + * + * The difference between the algorithm in the thesis and the one in this + * file is that the one in this file uses a ewma instead of a window. + * + */ + +static void ath_rate_ctl_start(struct ath_softc *, struct ieee80211_node *); + +static __inline int size_to_bin(int size) +{ + int x = 0; + for (x = 0; x < NUM_PACKET_SIZE_BINS; x++) { + if (size < packet_size_bins[x]) { + return x; + } + } + return NUM_PACKET_SIZE_BINS-1; +} +static __inline int bin_to_size(int index) { + return packet_size_bins[index]; +} + +/* + * Setup rate codes for management/control frames. We force + * all such frames to the lowest rate. + */ +static void +ath_rate_setmgtrates(struct ath_softc *sc, struct ath_node *an) +{ + const HAL_RATE_TABLE *rt = sc->sc_currates; + + /* setup rates for management frames */ + /* XXX management/control frames always go at lowest speed */ + an->an_tx_mgtrate = rt->info[0].rateCode; + an->an_tx_mgtratesp = an->an_tx_mgtrate + | rt->info[0].shortPreamble; +} + +void +ath_rate_node_init(struct ath_softc *sc, struct ath_node *an) +{ + DPRINTF(sc, "%s:\n", __func__); + /* NB: assumed to be zero'd by caller */ + ath_rate_setmgtrates(sc, an); +} + +void +ath_rate_node_cleanup(struct ath_softc *sc, struct ath_node *an) +{ + DPRINTF(sc, "%s:\n", __func__); +} + + +/* + * returns the ndx with the lowest average_tx_time, + * or -1 if all the average_tx_times are 0. + */ +static __inline int best_rate_ndx(struct sample_node *sn, int size_bin) +{ + int x = 0; + int best_rate_ndx = 0; + int best_rate_tt = 0; + for (x = 0; x < sn->num_rates; x++) { + int tt = sn->stats[size_bin][x].average_tx_time; + if (tt > 0) { + if (!best_rate_tt || best_rate_tt > tt) { + best_rate_tt = tt; + best_rate_ndx = x; + } + } + } + return (best_rate_tt) ? best_rate_ndx : -1; +} + +/* + * pick a ndx s.t. the perfect_tx_time + * is less than the best bit-rate's average_tx_time + * and the ndx has not had four successive failures. + */ +static __inline int pick_sample_ndx(struct sample_node *sn, int size_bin) +{ + int x = 0; + int best_ndx = best_rate_ndx(sn, size_bin); + int best_tt = 0; + int num_eligible = 0; + + if (best_ndx < 0) { + /* no successes yet, send at the lowest bit-rate */ + return 0; + } + + best_tt = sn->stats[size_bin][best_ndx].average_tx_time; + sn->sample_num[size_bin]++; + + /* + * first, find the number of bit-rates we could potentially + * sample. we assume this list doesn't change a lot, so + * we will just cycle through them. + */ + for (x = 0; x < sn->num_rates; x++) { + if (x != best_ndx && + sn->stats[size_bin][x].perfect_tx_time < best_tt && + sn->stats[size_bin][x].successive_failures < 4) { + num_eligible++; + } + } + + if (num_eligible > 0) { + int pick = sn->sample_num[size_bin] % num_eligible; + for (x = 0; x < sn->num_rates; x++) { + if (x != best_ndx && + sn->stats[size_bin][x].perfect_tx_time < best_tt && + sn->stats[size_bin][x].successive_failures < 4) { + if (pick == 0) { + return x; + } + pick--; + } + } + } + return best_ndx; +} + +void +ath_rate_findrate(struct ath_softc *sc, struct ath_node *an, + HAL_BOOL shortPreamble, size_t frameLen, + u_int8_t *rix, int *try0, u_int8_t *txrate) +{ + struct sample_node *sn = ATH_NODE_SAMPLE(an); + struct sample_softc *ssc = ATH_SOFTC_SAMPLE(sc); + int x; + int ndx = 0; + int size_bin = size_to_bin(frameLen); + int best_ndx = best_rate_ndx(sn, size_bin); + + if (sn->static_rate_ndx != -1) { + *try0 = 4; + *rix = sn->rates[sn->static_rate_ndx].rix; + *txrate = sn->rates[sn->static_rate_ndx].rateCode; + return; + } + + *try0 = 2; + + best_ndx = best_rate_ndx(sn, size_bin); + if (!sn->packets_sent[size_bin] || + sn->packets_sent[size_bin] % ssc->ath_sample_rate > 0) { + /* + * for most packets, send the packet at the bit-rate with + * the lowest estimated transmission time. + */ + if (best_ndx != -1) { + ndx = best_ndx; + } else { + /* + * no packet has succeeded, try the highest bitrate + * that hasn't failed. + */ + for (ndx = sn->num_rates-1; ndx >= 0; ndx--) { + if (sn->stats[size_bin][ndx].successive_failures == 0) { + break; + } + } + } + if (size_bin == 0) { + /* update the visible txrate for this node */ + an->an_node.ni_txrate = ndx; + } + } else { + /* + * before we pick a bit-rate to "sample", clear any + * stale stuff out. + */ + for (x = 0; x < sn->num_rates; x++) { + if (ticks - sn->stats[size_bin][x].last_tx > ((hz * 10000)/1000)) { + sn->stats[size_bin][x].average_tx_time = sn->stats[size_bin][x].perfect_tx_time; + sn->stats[size_bin][x].successive_failures = 0; + sn->stats[size_bin][x].tries = 0; + sn->stats[size_bin][x].total_packets = 0; + sn->stats[size_bin][x].packets_acked = 0; + } + } + + /* send the packet at a different bit-rate */ + ndx = pick_sample_ndx(sn, size_bin); + } + + + *rix = sn->rates[ndx].rix; + if (shortPreamble) { + *txrate = sn->rates[ndx].shortPreambleRateCode; + } else { + + *txrate = sn->rates[ndx].rateCode; + } + + sn->packets_sent[size_bin]++; +} + +void +ath_rate_setupxtxdesc(struct ath_softc *sc, struct ath_node *an, + struct ath_desc *ds, HAL_BOOL shortPreamble, u_int8_t rix) +{ + struct sample_node *sn = ATH_NODE_SAMPLE(an); + int rateCode = -1; + int frame_size; + int size_bin; + int best_ndx; + + frame_size = ds->ds_ctl0 & 0x0fff; /* low-order 12 bits of ds_ctl0 */ + if (frame_size == 0) + frame_size = 1500; + size_bin = size_to_bin(frame_size); + best_ndx = best_rate_ndx(sn, size_bin); + + if (best_ndx == -1 || !sn->stats[size_bin][best_ndx].packets_acked) { + /* + * no packet has succeeded, so also try twice at the lowest bitate. + */ + if (shortPreamble) { + rateCode = sn->rates[0].shortPreambleRateCode; + } else { + rateCode = sn->rates[0].rateCode; + } + } else if (sn->rates[best_ndx].rix != rix) { + /* + * we're trying a different bit-rate, and it could be lossy, + * so if it fails try at the best bit-rate. + */ + if (shortPreamble) { + rateCode = sn->rates[MAX(0,best_ndx-1)].shortPreambleRateCode; + } else { + rateCode = sn->rates[MAX(0,best_ndx-1)].rateCode; + } + } + if (rateCode != -1) { + ath_hal_setupxtxdesc(sc->sc_ah, ds + , rateCode, 1 /* series 1 */ + , rateCode, 1 /* series 2 */ + , rateCode, 1 /* series 3 */ + ); + } + +} + +void +ath_rate_tx_complete(struct ath_softc *sc, + struct ath_node *an, const struct ath_desc *ds) +{ + struct sample_node *sn = ATH_NODE_SAMPLE(an); + struct sample_softc *ssc = ATH_SOFTC_SAMPLE(sc); + int rate = sc->sc_hwmap[ds->ds_txstat.ts_rate &~ HAL_TXSTAT_ALTRATE].ieeerate; + int retries = ds->ds_txstat.ts_longretry; + int initial_rate_failed = ((ds->ds_txstat.ts_rate & HAL_TXSTAT_ALTRATE) + || ds->ds_txstat.ts_status != 0 || + retries > 3); + int tt = 0; + int rix = -1; + int x = 0; + int frame_size; /* low-order 12 bits of ds_ctl0 */ + int size_bin; + int size; + + if (!sn->num_rates) { + DPRINTF(sc, "%s: no rates yet\n", __func__); + return; + } + for (x = 0; x < sn->num_rates; x++) { + if (sn->rates[x].rate == rate) { + rix = x; + break; + } + } + + if (rix < 0 || rix > sn->num_rates) { + /* maybe a management packet */ + return; + } + + frame_size = ds->ds_ctl0 & 0x0fff; /* low-order 12 bits of ds_ctl0 */ + if (frame_size == 0) + frame_size = 1500; + size_bin = size_to_bin(frame_size); + size = bin_to_size(size_bin); + tt = calc_usecs_unicast_packet(sc, size, sn->rates[rix].rix, + retries); + + DPRINTF(sc, "%s: rate %d rix %d frame_size %d (%d) retries %d status %d tt %d avg_tt %d perfect_tt %d ts-rate %d\n", + __func__, rate, rix, frame_size, size, retries, initial_rate_failed, tt, + sn->stats[size_bin][rix].average_tx_time, + sn->stats[size_bin][rix].perfect_tx_time, + ds->ds_txstat.ts_rate); + + if (sn->stats[size_bin][rix].total_packets < 7) { + /* just average the first few packets */ + int avg_tx = sn->stats[size_bin][rix].average_tx_time; + int packets = sn->stats[size_bin][rix].total_packets; + sn->stats[size_bin][rix].average_tx_time = (tt+(avg_tx*packets))/(packets+1); + } else { + /* use a ewma */ + sn->stats[size_bin][rix].average_tx_time = + ((sn->stats[size_bin][rix].average_tx_time * ssc->ath_smoothing_rate) + + (tt * (100 - ssc->ath_smoothing_rate))) / 100; + } + + if (initial_rate_failed) { + /* + * this packet failed - count this as a failure + * for larger packets also, since we assume + * if a small packet fails at a lower bit-rate + * then a larger one will also. + */ + int y; + for (y = size_bin; y < NUM_PACKET_SIZE_BINS; y++) { + sn->stats[y][rix].successive_failures++; + sn->stats[y][rix].last_tx = ticks; + } + } else { + sn->stats[size_bin][rix].packets_acked++; + sn->stats[size_bin][rix].successive_failures = 0; + } + sn->stats[size_bin][rix].tries += (1+retries); + sn->stats[size_bin][rix].last_tx = ticks; + sn->stats[size_bin][rix].total_packets++; +} + +void +ath_rate_newassoc(struct ath_softc *sc, struct ath_node *an, int isnew) +{ + DPRINTF(sc, "%s:\n", __func__); + if (isnew) + ath_rate_ctl_start(sc, &an->an_node); +} + +static void +ath_rate_ctl_reset(struct ath_softc *sc, struct ieee80211_node *ni) +{ + struct ath_node *an = ATH_NODE(ni); + struct sample_node *sn = ATH_NODE_SAMPLE(an); + int x = 0; + int y = 0; + + for (y = 0; y < NUM_PACKET_SIZE_BINS; y++) { + int size = bin_to_size(y); + sn->packets_sent[y] = 0; + sn->sample_num[y] = 0; + + for (x = 0; x < ni->ni_rates.rs_nrates; x++) { + sn->stats[y][x].successive_failures = 0; + sn->stats[y][x].tries = 0; + sn->stats[y][x].total_packets = 0; + sn->stats[y][x].packets_acked = 0; + sn->stats[y][x].last_tx = 0; + sn->stats[y][x].perfect_tx_time = calc_usecs_unicast_packet(sc, size, + sn->rates[x].rix, + 0); + sn->stats[y][x].average_tx_time = sn->stats[y][x].perfect_tx_time; + + + DPRINTF(sc, "%s: %d rate %d rix %d rateCode %d perfect_tx_time %d \n", __func__, + x, sn->rates[x].rate, + sn->rates[x].rix, sn->rates[x].rateCode, + sn->stats[0][x].perfect_tx_time); + } + + } + + /* set the visible bit-rate to the lowest one available */ + ni->ni_txrate = 0; + +} + +/* + * Initialize the tables for a node. + */ +static void +ath_rate_ctl_start(struct ath_softc *sc, struct ieee80211_node *ni) +{ +#define RATE(_ix) (ni->ni_rates.rs_rates[(_ix)] & IEEE80211_RATE_VAL) + struct ieee80211com *ic = &sc->sc_ic; + struct ath_node *an = ATH_NODE(ni); + struct sample_node *sn = ATH_NODE_SAMPLE(an); + const HAL_RATE_TABLE *rt = sc->sc_currates; + + int x; + int srate; + + DPRINTF(sc, "%s:\n", __func__); + KASSERT(rt != NULL, ("no rate table, mode %u", sc->sc_curmode)); + KASSERT(ni->ni_rates.rs_nrates > 0, ("no rates")); + sn->static_rate_ndx = -1; + if (ic->ic_fixed_rate != -1) { + /* + * A fixed rate is to be used; ic_fixed_rate is an + * index into the supported rate set. Convert this + * to the index into the negotiated rate set for + * the node. We know the rate is there because the + * rate set is checked when the station associates. + */ + const struct ieee80211_rateset *rs = + &ic->ic_sup_rates[ic->ic_curmode]; + int r = rs->rs_rates[ic->ic_fixed_rate] & IEEE80211_RATE_VAL; + /* NB: the rate set is assumed sorted */ + srate = ni->ni_rates.rs_nrates - 1; + for (; srate >= 0 && RATE(srate) != r; srate--) + ; + KASSERT(srate >= 0, + ("fixed rate %d not in rate set", ic->ic_fixed_rate)); + sn->static_rate_ndx = srate; + + } + sn->num_rates = ni->ni_rates.rs_nrates; + for (x = 0; x < ni->ni_rates.rs_nrates; x++) { + sn->rates[x].rate = ni->ni_rates.rs_rates[x] & IEEE80211_RATE_VAL; + sn->rates[x].rix = sc->sc_rixmap[sn->rates[x].rate]; + sn->rates[x].rateCode = rt->info[sn->rates[x].rix].rateCode; + sn->rates[x].shortPreambleRateCode = + rt->info[sn->rates[x].rix].rateCode | + rt->info[sn->rates[x].rix].shortPreamble; + } + ath_rate_ctl_reset(sc, ni); + +#undef RATE +} + +/* + * Reset the rate control state for each 802.11 state transition. + */ +void +ath_rate_newstate(struct ath_softc *sc, enum ieee80211_state state) +{ + struct ieee80211com *ic = &sc->sc_ic; + + if (state == IEEE80211_S_RUN) + ath_rate_newassoc(sc, ATH_NODE(ic->ic_bss), 1); +} + +static void +ath_rate_sysctlattach(struct ath_softc *sc, struct sample_softc *osc) +{ + struct sysctl_ctx_list *ctx = device_get_sysctl_ctx(sc->sc_dev); + struct sysctl_oid *tree = device_get_sysctl_tree(sc->sc_dev); + + /* XXX bounds check [0..100] */ + SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO, + "smoothing_rate", CTLFLAG_RW, &osc->ath_smoothing_rate, 0, + "rate control: retry threshold to credit rate raise (%%)"); + /* XXX bounds check [2..100] */ + SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO, + "sample_rate", CTLFLAG_RW, &osc->ath_sample_rate,0, + "rate control: # good periods before raising rate"); +} + +struct ath_ratectrl * +ath_rate_attach(struct ath_softc *sc) +{ + struct sample_softc *osc; + + DPRINTF(sc, "%s:\n", __func__); + osc = malloc(sizeof(struct sample_softc), M_DEVBUF, M_NOWAIT|M_ZERO); + if (osc == NULL) + return NULL; + osc->arc.arc_space = sizeof(struct sample_node); + osc->ath_smoothing_rate = 95; /* ewma percentage (out of 100) */ + osc->ath_sample_rate = 10; /* send a different bit-rate 1/X packets */ + ath_rate_sysctlattach(sc, osc); + return &osc->arc; +} + +void +ath_rate_detach(struct ath_ratectrl *arc) +{ + struct sample_softc *osc = (struct sample_softc *) arc; + + free(osc, M_DEVBUF); +} + +/* + * Module glue. + */ +static int +sample_modevent(module_t mod, int type, void *unused) +{ + switch (type) { + case MOD_LOAD: + if (bootverbose) + printf("ath_rate: <SampleRate bit-rate selection algorithm>\n"); + return 0; + case MOD_UNLOAD: + return 0; + } + return EINVAL; +} + +static moduledata_t sample_mod = { + "ath_rate", + sample_modevent, + 0 +}; +DECLARE_MODULE(ath_rate, sample_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST); +MODULE_VERSION(ath_rate, 1); +MODULE_DEPEND(ath_rate, wlan, 1, 1, 1); |