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madwifi/ath_rate/minstrel/minstrel.c

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/*-
* 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.
*
* $Id: minstrel.c 1525 2006-04-23 21:05:57Z dyqith $
*/
/* And then Indranet Technologies Ltd sponsored Derek Smithies to work
* on this code. Derek Smithies (derek@indranet.co.nz) took parts of the
* adm module and pasted it into this code base.
*
* This version of John Bicket's code takes the experimental approach one
* step further.
* When in auto rate mode, packets are sent at the selected rate.
* The Hal asks for what alternative rate to use if the selected rate fails.
* We provide the alternative rate from a random selection of 1.. max rate.
* Given the probability of success, multiplied with the transmission time,
* we can determine the rate which maximises packet throughput.
*
* Different rates are used for every remote node - some nodes will work
* better on different rates.
* Every second, a timer fires, to assess the throughput at each rate with
* each remote node.
* This timer will then determine the optimum rate for each remote node, based
* on the performance figures.
*
* This code is called minstrel, because we have taken a wandering minstrel
* approach. Wander around the different rates, singing wherever
* you can. And then, look at the performance, and make a choice.
*
* It is not an aimless search, there is some direction to the search
* pattern. But then, the minstels of old only sung where they thought
* they would get an income. Similarily, we direct thesearch a little.
*
* Enjoy. Derek Smithies. */
/* 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 an EWMA instead of a window.
*
* Also, this implementation tracks the average transmission time for
* a few different packet sizes independently for each link. */
#ifndef AUTOCONF_INCLUDED
#include <linux/config.h>
#endif
#include <linux/version.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/random.h>
#include <linux/delay.h>
#include <linux/cache.h>
#include <linux/sysctl.h>
#include <linux/proc_fs.h>
#include <linux/if_arp.h>
#include <linux/net.h> /* for net_random */
#include <linux/vmalloc.h>
#include <asm/uaccess.h>
#include <net80211/if_media.h>
#include <net80211/ieee80211_var.h>
#include <net80211/ieee80211_rate.h>
#include "if_athvar.h"
#include "if_ath_hal.h"
#include "ah_desc.h"
#include "minstrel.h"
#define MINSTREL_DEBUG
#ifdef MINSTREL_DEBUG
enum {
ATH_DEBUG_RATE = 0x00000010 /* rate control */
};
#define DPRINTF(sc, _fmt, ...) do { \
if (sc->sc_debug & ATH_DEBUG_RATE) \
printk("%s: " _fmt, SC_DEV_NAME(sc), __VA_ARGS__); \
} while (0)
#else
#define DPRINTF(sc, _fmt, ...)
#endif
#define ONE_SECOND (1000 * 1000) /* 1 second, or 1000 milliseconds; eternity, in other words */
#include "release.h"
#if 0
static char *version = "1.2 (" RELEASE_VERSION ")";
#endif
static char *dev_info = "ath_rate_minstrel";
#define STALE_FAILURE_TIMEOUT_MS 10000
#define ENABLE_MRR 1
/* Interval (in ms) between successive rate statistics, default to 100 ms. */
static int ath_timer_interval = 100;
/* 10% of the time, send a packet at something other than the optimal rate,
* which fills the statistics tables nicely. This percentage is applied to the
* first packet of the multi rate retry chain. */
static int ath_lookaround_rate = 10;
static int ath_ewma_level = 75;
static int ath_segment_size = 6000;
static void ath_rate_ctl_reset(struct ath_softc *, struct ieee80211_node *);
/* Calculate the throughput and probability of success for each node
* we are talking on, based on the statistics collected during the
* last timer period. */
static void ath_rate_statistics(void *arg, struct ieee80211_node *ni);
#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,52))
MODULE_PARM(ath_lookaround_rate, "i");
MODULE_PARM(ath_ewma_level, "i");
MODULE_PARM(ath_segment_size, "i");
#else
#include <linux/moduleparam.h>
module_param(ath_lookaround_rate, int, 0600);
module_param(ath_ewma_level, int, 0600);
module_param(ath_segment_size, int, 0600);
#endif
MODULE_PARM_DESC(ath_lookaround_rate, " % of packets sent to fill statistics "
"table (10) ");
MODULE_PARM_DESC(ath_ewma_level, " scaling % used in ewma rolloff "
"calculations (75) ");
MODULE_PARM_DESC(ath_segment_size, " max duration of time to spend in either "
"of the first two mrr segments (6000)");
static __inline int
rate_to_ndx(struct minstrel_node *sn, int rate)
{
unsigned int x = 0;
for (x = 0; x < sn->num_rates; x++)
if (sn->rates[x].rate == rate)
return x;
return -1;
}
/* Calculate the transmit duration of a frame. */
static unsigned
calc_usecs_unicast_packet(struct ath_softc *sc, int length,
int rix, int short_retries, int long_retries)
{
const HAL_RATE_TABLE *rt = sc->sc_currates;
struct ieee80211com *ic = &sc->sc_ic;
unsigned t_slot = 20;
unsigned t_difs = 50;
unsigned t_sifs = 10;
unsigned int x = 0, tt = 0;
unsigned int cix = rt->info[rix].controlRate;
int rts = 0, cts = 0;
int cw = ATH_DEFAULT_CWMIN;
KASSERT(rt != NULL, ("no rate table, mode %u", sc->sc_curmode));
if (!rt->info[rix].rateKbps) {
printk(KERN_WARNING "rix %d (%d) bad ratekbps %d mode %u\n",
rix, rt->info[rix].dot11Rate,
rt->info[rix].rateKbps,
sc->sc_curmode);
return 0;
}
/* XXX: Getting MAC/PHY level timings should be fixed for turbo
* rates, and there is probably a way to get this from the
* HAL... */
switch (rt->info[rix].phy) {
case IEEE80211_T_OFDM:
#if 0
t_slot = 9;
t_sifs = 16;
t_difs = 28;
/* fall through */
#endif
case IEEE80211_T_TURBO:
t_slot = 9;
t_sifs = 8;
t_difs = 28;
break;
case IEEE80211_T_DS:
/* Fall through to default */
default:
/* pg. 205 ieee.802.11.pdf */
t_slot = 20;
t_difs = 50;
t_sifs = 10;
}
if ((ic->ic_flags & IEEE80211_F_USEPROT) &&
(rt->info[rix].phy == IEEE80211_T_OFDM)) {
if (ic->ic_protmode == IEEE80211_PROT_RTSCTS)
rts = 1;
else if (ic->ic_protmode == IEEE80211_PROT_CTSONLY)
cts = 1;
cix = rt->info[sc->sc_protrix].controlRate;
}
#if 0
if (length > ic->ic_rtsthreshold)
rts = 1;
#endif
if (rts || cts) {
int ctsrate = rt->info[cix].rateCode;
int ctsduration = 0;
if (!rt->info[cix].rateKbps) {
#if 0
printk(KERN_WARNING
"cix %d (%d) bad ratekbps %d mode %u\n",
cix, rt->info[cix].dot11Rate,
rt->info[cix].rateKbps,
sc->sc_curmode);
#endif
return 0;
}
ctsrate |= rt->info[cix].shortPreamble;
if (rts) /* SIFS + CTS */
ctsduration += rt->info[cix].spAckDuration;
ctsduration += ath_hal_computetxtime(sc->sc_ah,
rt, length, rix, AH_TRUE);
if (cts) /* SIFS + ACK */
ctsduration += rt->info[cix].spAckDuration;
tt += (short_retries + 1) * ctsduration;
}
tt += t_difs;
tt += (long_retries + 1) * (t_sifs + rt->info[rix].spAckDuration);
tt += (long_retries + 1) * ath_hal_computetxtime(sc->sc_ah, rt, length,
rix, AH_TRUE);
for (x = 0; x <= short_retries + long_retries; x++) {
cw = MIN(ATH_DEFAULT_CWMAX, (cw + 1) * 2);
tt += (t_slot * cw / 2);
}
return tt;
}
static void
ath_rate_node_init(struct ath_softc *sc, struct ath_node *an)
{
/* NB: Assumed to be zero'd by caller */
ath_rate_ctl_reset(sc, &an->an_node);
}
static void
ath_rate_node_cleanup(struct ath_softc *sc, struct ath_node *an)
{
}
#if 0
static void
ath_rate_node_copy(struct ath_softc *sc,
struct ath_node *dst, const struct ath_node *src)
{
struct minstrel_node *odst = ATH_NODE_MINSTREL(dst);
const struct minstrel_node *osrc =
(const struct minstrel_node *)&src[1];
memcpy(odst, osrc, sizeof(struct minstrel_node));
}
#endif
static void
ath_rate_findrate(struct ath_softc *sc, struct ath_node *an,
int shortPreamble, size_t frameLen,
u_int8_t *rix, unsigned int *try0, u_int8_t *txrate)
{
struct minstrel_node *sn = ATH_NODE_MINSTREL(an);
struct ieee80211com *ic = &sc->sc_ic;
unsigned int ndx, offset;
int mrr;
if (sn->num_rates <= 0) {
printk(KERN_WARNING "%s: no rates for " MAC_FMT "?\n",
dev_info,
MAC_ADDR(an->an_node.ni_macaddr));
return;
}
mrr = sc->sc_mrretry &&
!(ic->ic_flags & IEEE80211_F_USEPROT) &&
ENABLE_MRR;
if (sn->static_rate_ndx >= 0) {
ndx = sn->static_rate_ndx;
} else {
sn->packet_count++;
sn->random_n = (sn->a * sn->random_n) + sn->b;
offset = sn->random_n & 0xf;
if ((((100 * sn->sample_count) / sn->packet_count) <
ath_lookaround_rate) &&
(offset < 2)) {
sn->sample_count++;
sn->is_sampling = 1;
if (sn->packet_count >= 10000) {
sn->sample_count = 0;
sn->packet_count = 0;
}
/* Don't look for slowest rate (i.e. slowest
* base rate). We must presume that the slowest
* rate works fine, or else other management
* frames will also be failing - therefore the
* link will soon be broken anyway. Indeed,
* the slowest rate was used to establish the
* link in the first place. */
ndx = sn->rs_sampleTable[sn->rs_sampleIndex]
[sn->rs_sampleColumn];
sn->rs_sampleIndex++;
if (sn->rs_sampleIndex > (sn->num_rates - 2)) {
sn->rs_sampleIndex = 0;
sn->rs_sampleColumn++;
if (sn->rs_sampleColumn >= MINSTREL_COLUMNS)
sn->rs_sampleColumn = 0;
}
sn->rs_sample_rate = ndx;
sn->rs_sample_rate_slower =
(sn->perfect_tx_time[ndx] >
sn->perfect_tx_time[sn->max_tp_rate]);
if (sn->rs_sample_rate_slower)
ndx = sn->max_tp_rate;
} else
ndx = sn->max_tp_rate;
}
if ((sn->static_rate_ndx != -1) || !mrr)
*try0 = ATH_TXMAXTRY;
else
*try0 = sn->retry_adjusted_count[ndx];
KASSERT((ndx < sn->num_rates),
("%s: bad ndx (%d/%d) for " MAC_FMT "?",
dev_info, ndx, sn->num_rates,
MAC_ADDR(an->an_node.ni_macaddr)));
*rix = sn->rates[ndx].rix;
if (shortPreamble)
*txrate = sn->rates[ndx].shortPreambleRateCode;
else
*txrate = sn->rates[ndx].rateCode;
}
static void
ath_rate_get_mrr(struct ath_softc *sc, struct ath_node *an, int shortPreamble,
size_t frame_size, u_int8_t rix, struct ieee80211_mrr *mrr)
{
struct minstrel_node *sn = ATH_NODE_MINSTREL(an);
/* Index into the rate table, so for example, it is 0..11. */
int rc1, rc2, rc3;
if (sn->is_sampling) {
sn->is_sampling = 0;
if (sn->rs_sample_rate_slower)
rc1 = sn->rs_sample_rate;
else
rc1 = sn->max_tp_rate;
} else {
rc1 = sn->max_tp_rate2;
}
rc2 = sn->max_prob_rate;
rc3 = 0;
KASSERT((rc1 >= 0) && (rc1 < sn->num_rates),
("%s: bad rc1 (%d/%d) for " MAC_FMT "?",
dev_info, rc1, sn->num_rates,
MAC_ADDR(an->an_node.ni_macaddr)));
KASSERT((rc2 >= 0) && (rc2 < sn->num_rates),
("%s: bad rc2 (%d/%d) for " MAC_FMT "?",
dev_info, rc2, sn->num_rates,
MAC_ADDR(an->an_node.ni_macaddr)));
KASSERT((rc3 >= 0) && (rc3 < sn->num_rates),
("%s: bad rc3 (%d/%d) for " MAC_FMT "?",
dev_info, rc3, sn->num_rates,
MAC_ADDR(an->an_node.ni_macaddr)));
if (shortPreamble) {
mrr->rate1 = sn->rates[rc1].shortPreambleRateCode;
mrr->rate2 = sn->rates[rc2].shortPreambleRateCode;
mrr->rate3 = sn->rates[rc3].shortPreambleRateCode;
} else {
mrr->rate1 = sn->rates[rc1].rateCode;
mrr->rate2 = sn->rates[rc2].rateCode;
mrr->rate3 = sn->rates[rc3].rateCode;
}
mrr->retries1 = sn->retry_adjusted_count[rc1];
mrr->retries2 = sn->retry_adjusted_count[rc2];
mrr->retries3 = sn->retry_adjusted_count[rc3];
}
static void
ath_rate_tx_complete(struct ath_softc *sc,
struct ath_node *an, const struct ath_buf *bf)
{
struct minstrel_node *sn = ATH_NODE_MINSTREL(an);
struct ieee80211com *ic = &sc->sc_ic;
const struct ath_tx_status *ts = &bf->bf_dsstatus.ds_txstat;
const struct ath_desc *ds = &bf->bf_desc[0];
int final_rate = 0;
int tries = 0;
int mrr;
int final_ndx;
int rate0, tries0, ndx0;
int rate1, tries1, ndx1;
int rate2, tries2, ndx2;
int rate3, tries3, ndx3;
/* This is the index in the retry chain we finish at.
* With no retransmits, it is always 0.
* int finalTSIdx = ads->final_ts_index; */
final_rate = sc->sc_hwmap[ts->ts_rate & ~HAL_TXSTAT_ALTRATE].ieeerate;
final_ndx = rate_to_ndx(sn, final_rate);
if (final_ndx >= sn->num_rates) {
DPRINTF(sc, "%s: final ndx too high\n", __func__);
final_ndx = 0;
}
if (final_ndx < 0) {
DPRINTF(sc, "%s: final ndx too low\n", __func__);
final_ndx = 0;
}
/* 'tries' is the total number of times we have endeavoured to
* send this packet, and is a sum of the #attempts at each
* level in the multi-rate retry chain. */
tries = ts->ts_longretry + 1;
if (sn->num_rates <= 0) {
DPRINTF(sc, "%s: " MAC_FMT " %s no rates yet\n", dev_info,
MAC_ADDR(an->an_node.ni_macaddr), __func__);
return;
}
if (!ts->ts_status) /* Success when sending a packet*/
sn->rs_ratesuccess[final_ndx]++;
mrr = sc->sc_mrretry &&
!(ic->ic_flags & IEEE80211_F_USEPROT) &&
ENABLE_MRR;
if (!mrr) {
if ((0 <= final_ndx) && (final_ndx < sn->num_rates)) {
/* only one rate was used */
sn->rs_rateattempts[final_ndx] += tries;
}
return;
}
/* Now, query the HAL/hardware to find out the contents of the
* multirate retry chain. If we have it set to 6, 3, 2, 2, this
* call will always return 6,3,2,2. For some packets, we can
* get a mrr of 0, -1, -1, -1, which indicates there is no
* chain installed for that packet */
rate0 = sc->sc_hwmap[MS(ds->ds_ctl3, AR_XmitRate0)].ieeerate;
tries0 = MS(ds->ds_ctl2, AR_XmitDataTries0);
ndx0 = rate_to_ndx(sn, rate0);
rate1 = sc->sc_hwmap[MS(ds->ds_ctl3, AR_XmitRate1)].ieeerate;
tries1 = MS(ds->ds_ctl2, AR_XmitDataTries1);
ndx1 = rate_to_ndx(sn, rate1);
rate2 = sc->sc_hwmap[MS(ds->ds_ctl3, AR_XmitRate2)].ieeerate;
tries2 = MS(ds->ds_ctl2, AR_XmitDataTries2);
ndx2 = rate_to_ndx(sn, rate2);
rate3 = sc->sc_hwmap[MS(ds->ds_ctl3, AR_XmitRate3)].ieeerate;
tries3 = MS(ds->ds_ctl2, AR_XmitDataTries3);
ndx3 = rate_to_ndx(sn, rate3);
sn->rs_rateattempts[ndx0] += MIN(tries, tries0);
if (tries <= tries0)
return;
if (tries1 < 0)
return;
tries = tries - tries0;
sn->rs_rateattempts[ndx1] += MIN(tries, tries1);
if (tries <= tries1)
return;
if (tries2 < 0)
return;
tries = tries - tries1;
sn->rs_rateattempts[ndx2] += MIN(tries, tries2);
if (tries <= tries2)
return;
if (tries3 < 0)
return;
tries = tries - tries2;
sn->rs_rateattempts[ndx3] += MIN(tries, tries3);
}
static void
ath_rate_newassoc(struct ath_softc *sc, struct ath_node *an, int isnew)
{
DPRINTF(sc, "%s: " MAC_FMT " %s\n", dev_info,
MAC_ADDR(an->an_node.ni_macaddr), __func__);
if (isnew)
ath_rate_ctl_reset(sc, &an->an_node);
}
static void
ath_fill_sample_table(struct ath_softc *sc, struct minstrel_node *sn)
{
unsigned int num_sample_rates = (sn->num_rates - 1);
/* newIndex varies as 0 .. (num_rates - 2)
* The highest index rate is the slowest and is ignored */
unsigned int i, column_index, newIndex;
u_int8_t random_bytes[8];
/* This should be unnecessary if we are assuming storage is provided
* as zeroed */
memset(sn->rs_sampleTable, 0, sizeof(sn->rs_sampleTable));
sn->rs_sampleColumn = 0;
sn->rs_sampleIndex = 0;
/* Seed value to random number generator, which determines when we
* send a sample packet at some non-optimal rate
* FIXME: randomise? */
sn->random_n = 1;
sn->a = 1664525;
sn->b = 1013904223;
if (sn->num_rates > 1) {
for (column_index = 0; column_index < MINSTREL_COLUMNS; column_index++) {
for (i = 0; i < num_sample_rates; i++) {
get_random_bytes(random_bytes, 8);
newIndex = (i + random_bytes[i & 7]) % num_sample_rates;
while (sn->rs_sampleTable[newIndex][column_index] != 0)
newIndex = (newIndex + 1) % num_sample_rates;
sn->rs_sampleTable[newIndex][column_index] = i + 1;
}
}
}
for (column_index = 0; column_index < MINSTREL_COLUMNS; column_index++) {
for (i = 0; i < num_sample_rates && i < IEEE80211_RATE_MAXSIZE; i++) {
DPRINTF(sc, "rs_sampleTable[%2u][%2u] = %2u\n",
i, column_index, sn->rs_sampleTable[i][column_index]);
}
}
}
/* Initialize the tables for a node. */
static void
ath_rate_ctl_reset(struct ath_softc *sc, struct ieee80211_node *ni)
{
struct minstrel_node *sn = ATH_NODE_MINSTREL(ATH_NODE(ni));
struct ieee80211vap *vap = ni->ni_vap;
const HAL_RATE_TABLE *rt = sc->sc_currates;
unsigned int x;
int retry_index, tx_time;
int srate;
int ndx = 0;
sn->num_rates = 0;
sn->max_tp_rate = 0;
sn->max_tp_rate2 = 0;
sn->max_prob_rate = 0;
sn->packet_count = 0;
sn->sample_count = 0;
sn->is_sampling = 0;
if (rt == NULL) {
DPRINTF(sc, "no rates yet! mode %u\n", sc->sc_curmode);
return;
}
sn->static_rate_ndx = -1;
sn->num_rates = ni->ni_rates.rs_nrates;
for (x = 0; x < ni->ni_rates.rs_nrates; x++) {
sn->rs_rateattempts [x] = 0;
sn->rs_thisprob [x] = 0;
sn->rs_ratesuccess [x] = 0;
sn->rs_lastrateattempts [x] = 0;
sn->rs_lastratesuccess [x] = 0;
sn->rs_probability [x] = 0;
sn->rs_succ_hist [x] = 0;
sn->rs_att_hist [x] = 0;
sn->rs_this_tp [x] = 0;
sn->rates[x].rate = ni->ni_rates.rs_rates[x] & IEEE80211_RATE_VAL;
sn->rates[x].rix = sc->sc_rixmap[sn->rates[x].rate];
if (sn->rates[x].rix == 0xff) {
DPRINTF(sc, "%s: %s ignore bogus rix at %d\n",
dev_info, __func__, x);
continue;
}
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_fill_sample_table(sc, sn);
ni->ni_txrate = 0;
if (sn->num_rates <= 0) {
DPRINTF(sc, "%s: %s " MAC_FMT " no rates (fixed %d) \n",
dev_info, __func__, MAC_ADDR(ni->ni_macaddr),
vap->iv_fixed_rate);
/* There are no rates yet; we're done */
return;
}
if (vap->iv_fixed_rate != IEEE80211_FIXED_RATE_NONE) {
srate = sn->num_rates - 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. */
/* NB: the rate set is assumed to be sorted. */
for (;
(srate >= 0) &&
(ni->ni_rates.rs_rates[srate] &
IEEE80211_RATE_VAL) != vap->iv_fixed_rate;
srate--);
KASSERT(srate >= 0,
("fixed rate %d not in rate set", vap->iv_fixed_rate));
sn->static_rate_ndx = srate;
ni->ni_txrate = srate;
DPRINTF(sc, "%s: %s " MAC_FMT " fixed rate %d%sMbps\n",
dev_info, __func__, MAC_ADDR(ni->ni_macaddr),
sn->rates[srate].rate / 2,
(sn->rates[srate].rate % 2) ? ".5 " : " ");
return;
}
for (x = 0; x < ni->ni_rates.rs_nrates; x++) {
if (sn->rates[x].rix == 0xff) {
DPRINTF(sc, "%s: %s ignore bogus rix at %d\n",
dev_info, __func__, x);
continue;
}
sn->rs_rateattempts [x] = 0;
sn->rs_thisprob [x] = 0;
sn->rs_ratesuccess [x] = 0;
sn->rs_probability [x] = 0;
sn->rs_lastrateattempts [x] = 0;
sn->rs_lastratesuccess [x] = 0;
sn->rs_succ_hist [x] = 0;
sn->rs_att_hist [x] = 0;
sn->perfect_tx_time [x] =
calc_usecs_unicast_packet(sc, 1200,
sn->rates[x].rix,
0, 0);
sn->retry_count [x] = 1;
sn->retry_adjusted_count[x] = 1;
for (retry_index = 2; retry_index < ATH_TXMAXTRY; retry_index++) {
tx_time = calc_usecs_unicast_packet(sc, 1200,
sn->rates[x].rix, 0, retry_index);
if (tx_time > ath_segment_size)
break;
sn->retry_count[x] = retry_index;
sn->retry_adjusted_count[x] = retry_index;
}
}
#if 0
DPRINTF(sc, "%s: Retry table for this node\n", __func__);
for (x = 0; x < ni->ni_rates.rs_nrates; x++)
DPRINTF(sc, "%2d %2d %6d \n", x, sn->retry_count[x],
sn->perfect_tx_time[x]);
#endif
/* Set the initial rate */
for (ndx = sn->num_rates - 1; ndx > 0; ndx--)
if (sn->rates[ndx].rate <= 72)
break;
sn->current_rate = ndx;
ni->ni_txrate = sn->current_rate;
}
static void
ath_rate_cb(void *arg, struct ieee80211_node *ni)
{
ath_rate_ctl_reset(ni->ni_ic->ic_dev->priv, ni);
}
/* Reset the rate control state for each 802.11 state transition. */
static void
ath_rate_newstate(struct ieee80211vap *vap, enum ieee80211_state newstate)
{
struct ieee80211com *ic = vap->iv_ic;
if (newstate == IEEE80211_S_RUN) {
if (ic->ic_opmode != IEEE80211_M_STA) {
/* Sync rates for associated stations and
* neighbors. */
ieee80211_iterate_nodes(&ic->ic_sta,
ath_rate_cb, NULL);
}
ath_rate_newassoc(ic->ic_dev->priv,
ATH_NODE(vap->iv_bss), 1);
}
}
static void
ath_timer_function(unsigned long data)
{
struct minstrel_softc *ssc = (struct minstrel_softc *)data;
struct ath_softc *sc = ssc->sc;
struct ieee80211com *ic;
struct net_device *dev = ssc->sc_dev;
struct timer_list *timer;
unsigned int interval = ath_timer_interval;
if (dev == NULL)
DPRINTF(sc, "%s: 'dev' is null in this timer \n", __func__);
if (sc == NULL)
DPRINTF(sc, "%s: 'sc' is null in this timer\n", __func__);
ic = &sc->sc_ic;
if (ssc->close_timer_now)
return;
if (dev->flags & IFF_RUNNING) {
sc->sc_stats.ast_rate_calls++;
if (ic->ic_opmode == IEEE80211_M_STA) {
struct ieee80211vap *tmpvap;
TAILQ_FOREACH(tmpvap, &ic->ic_vaps, iv_next) {
/* NB: no reference */
ath_rate_statistics(sc, tmpvap->iv_bss);
}
} else
ieee80211_iterate_nodes(&ic->ic_sta,
ath_rate_statistics, sc);
}
if (ic->ic_opmode == IEEE80211_M_STA)
interval = ath_timer_interval >> 1;
timer = &(ssc->timer);
if (timer == NULL)
DPRINTF(sc, "%s: timer is null - leave it\n", __func__);
mod_timer(timer, jiffies + ((HZ * interval) / 1000));
}
static void
ath_rate_statistics(void *arg, struct ieee80211_node *ni)
{
struct ath_node *an = (struct ath_node *)ni;
struct ieee80211_rateset *rs = &ni->ni_rates;
struct minstrel_node *rn = ATH_NODE_MINSTREL(an);
unsigned int i;
u_int32_t p;
u_int32_t micro_secs;
u_int32_t max_prob, index_max_prob;
u_int32_t max_tp, index_max_tp, index_max_tp2;
/* Calculate statistics for each date rate in the table */
/* 'micro_secs' is the time to transmit 1200 bytes, or 9600 bits. */
for (i = 0; i < rs->rs_nrates; i++) {
micro_secs = rn->perfect_tx_time[i];
if (micro_secs == 0)
micro_secs = ONE_SECOND;
if (rn->rs_rateattempts[i] != 0) {
p = (rn->rs_ratesuccess[i] * 18000) /
rn->rs_rateattempts[i];
rn->rs_succ_hist[i] += rn->rs_ratesuccess[i];
rn->rs_att_hist[i] += rn->rs_rateattempts[i];
rn->rs_thisprob[i] = p;
p = ((p * (100 - ath_ewma_level)) +
(rn->rs_probability[i] * ath_ewma_level)) / 100;
rn->rs_probability[i] = p;
rn->rs_this_tp[i] = p * (ONE_SECOND / micro_secs);
rn->rs_lastratesuccess[i] = rn->rs_ratesuccess[i];
rn->rs_lastrateattempts[i] = rn->rs_rateattempts[i];
rn->rs_ratesuccess[i] = 0;
rn->rs_rateattempts[i] = 0;
} else {
rn->rs_lastratesuccess[i] = 0;
rn->rs_lastrateattempts[i] = 0;
}
/* Sample less often below the 10% chance of success.
* Sample less often above the 95% chance of success.
* 'rn->rs_probability' has a scale of 0 (0%) to 18000 (100%),
* which avoids rounding issues.*/
if ((rn->rs_probability[i] > 17100) ||
(rn->rs_probability[i] < 1800)) {
rn->retry_adjusted_count[i] = rn->retry_count[i] >> 1;
if (rn->retry_adjusted_count[i] > 2)
rn->retry_adjusted_count[i] = 2;
} else
rn->retry_adjusted_count[i] = rn->retry_count[i];
if (rn->retry_adjusted_count[i] == 0)
rn->retry_adjusted_count[i] = 1;
}
/* The High speed rates (e.g 54Mbps) is checked last. If
* throughput is the same for two rates, we prefer the
* lower rate, as this has a better chance of success. */
max_prob = 0;
index_max_prob = 0;
max_tp = 0;
index_max_tp = 0;
index_max_tp2 = 0;
/* This code could have been moved up into the previous
* loop. More readable to have it here */
for (i = 0; i < rs->rs_nrates; i++) {
if (max_tp < rn->rs_this_tp[i]) {
index_max_tp = i;
max_tp = rn->rs_this_tp[i];
}
if (max_prob < rn->rs_probability[i]) {
index_max_prob = i;
max_prob = rn->rs_probability[i];
}
}
max_tp = 0;
for (i = 0; i < rs->rs_nrates; i++) {
if ((i != index_max_tp) && (max_tp < rn->rs_this_tp[i])) {
index_max_tp2 = i;
max_tp = rn->rs_this_tp[i];
}
}
rn->max_tp_rate = index_max_tp;
rn->max_tp_rate2 = index_max_tp2;
rn->max_prob_rate = index_max_prob;
rn->current_rate = index_max_tp;
}
static struct ath_ratectrl *
ath_rate_attach(struct ath_softc *sc)
{
struct minstrel_softc *osc;
DPRINTF(sc, "%s: %s\n", dev_info, __func__);
_MOD_INC_USE(THIS_MODULE, return NULL);
osc = kmalloc(sizeof(struct minstrel_softc), GFP_ATOMIC);
if (osc == NULL) {
_MOD_DEC_USE(THIS_MODULE);
return NULL;
}
osc->arc.arc_space = sizeof(struct minstrel_node);
osc->arc.arc_vap_space = 0;
osc->close_timer_now = 0;
init_timer(&osc->timer);
osc->sc = sc;
osc->sc_dev = sc->sc_dev;
osc->timer.function = ath_timer_function;
osc->timer.data = (unsigned long)osc;
mod_timer(&osc->timer, jiffies + HZ);
return &osc->arc;
}
static void
ath_rate_detach(struct ath_ratectrl *arc)
{
struct minstrel_softc *osc = (struct minstrel_softc *)arc;
osc->close_timer_now = 1;
del_timer(&osc->timer);
kfree(osc);
_MOD_DEC_USE(THIS_MODULE);
}
#ifdef CONFIG_SYSCTL
static int
ath_proc_read_nodes(struct ieee80211vap *vap, char *buf, int space)
{
char *p = buf;
struct ieee80211_node *ni;
struct minstrel_node *odst;
struct ieee80211_node_table *nt =
(struct ieee80211_node_table *)&vap->iv_ic->ic_sta;
unsigned int x = 0;
unsigned int this_tp, this_prob, this_eprob;
struct ath_softc *sc = vap->iv_ic->ic_dev->priv;;
IEEE80211_NODE_TABLE_LOCK_IRQ(nt);
TAILQ_FOREACH(ni, &nt->nt_node, ni_list) {
/* Assume each node needs 1500 bytes */
if ((buf + space) < (p + 1500)) {
if ((buf + space) > (p + 100)) {
p += sprintf(p, "out of room for node "
MAC_FMT "\n\n",
MAC_ADDR(ni->ni_macaddr));
break;
}
DPRINTF(sc, "%s: out of memeory to write "
"all of the nodes\n", __func__);
break;
}
odst = ATH_NODE_MINSTREL(ATH_NODE(ni));
/* Skip ourself */
if (IEEE80211_ADDR_EQ(vap->iv_myaddr, ni->ni_macaddr))
continue;
p += sprintf(p, "rate data for node: " MAC_FMT "\n",
MAC_ADDR(ni->ni_macaddr));
p += sprintf(p, " rate throughput EWMA prob this prob this "
"succ/attempt success attempts\n");
for (x = 0; x < odst->num_rates; x++) {
p += sprintf(p, "%c",
(x == odst->current_rate) ? 'T' : ' ');
p += sprintf(p, "%c",
(x == odst->max_tp_rate2) ? 't' : ' ');
p += sprintf(p, "%c",
(x == odst->max_prob_rate) ? 'P' : ' ');
p += sprintf(p, " %2u%s",
odst->rates[x].rate / 2,
(odst->rates[x].rate & 0x1) != 0 ?
".5" : " ");
this_tp = ((odst->rs_this_tp[x] / 18000) * 96) >> 10;
this_prob = odst->rs_thisprob[x] / 18;
this_eprob = odst->rs_probability[x] / 18;
p += sprintf(p, " %2u.%1u %2u.%1u %6u.%1u"
" %3u(%3u) %8llu %8llu\n",
this_tp / 10, this_tp % 10,
this_eprob / 10, this_eprob % 10,
this_prob / 10, this_prob % 10,
odst->rs_lastratesuccess[x],
odst->rs_lastrateattempts[x],
(unsigned long long)odst->rs_succ_hist[x],
(unsigned long long)odst->rs_att_hist[x]);
}
p += sprintf(p, "\n");
p += sprintf(p, "Total packet count:: ideal %d "
"lookaround %d\n\n",
odst->packet_count, odst->sample_count);
}
IEEE80211_NODE_TABLE_UNLOCK_IRQ(nt);
return (p - buf);
}
static int
ath_proc_ratesample_open(struct inode *inode, struct file *file)
{
struct proc_ieee80211_priv *pv = NULL;
struct proc_dir_entry *dp = PDE(inode);
struct ieee80211vap *vap = dp->data;
if (!(file->private_data = kzalloc(sizeof(struct proc_ieee80211_priv),
GFP_KERNEL)))
return -ENOMEM;
/* Initially allocate both read and write buffers */
pv = (struct proc_ieee80211_priv *)file->private_data;
pv->rbuf = vmalloc(MAX_PROC_IEEE80211_SIZE);
if (!pv->rbuf) {
kfree(pv);
return -ENOMEM;
}
pv->wbuf = vmalloc(MAX_PROC_IEEE80211_SIZE);
if (!pv->wbuf) {
vfree(pv->rbuf);
kfree(pv);
return -ENOMEM;
}
memset(pv->wbuf, 0, MAX_PROC_IEEE80211_SIZE);
memset(pv->rbuf, 0, MAX_PROC_IEEE80211_SIZE);
pv->max_wlen = MAX_PROC_IEEE80211_SIZE;
pv->max_rlen = MAX_PROC_IEEE80211_SIZE;
/* Now read the data into the buffer */
pv->rlen = ath_proc_read_nodes(vap, pv->rbuf, MAX_PROC_IEEE80211_SIZE);
return 0;
}
static struct file_operations ath_proc_ratesample_ops = {
.read = NULL,
.write = NULL,
.open = ath_proc_ratesample_open,
.release = NULL,
};
static void
ath_rate_dynamic_proc_register(struct ieee80211vap *vap)
{
/* Create proc entries for the rate control algorithm */
ieee80211_proc_vcreate(vap, &ath_proc_ratesample_ops, "rate_info");
}
#endif /* CONFIG_SYSCTL */
static struct ieee80211_rate_ops ath_rate_ops = {
.ratectl_id = IEEE80211_RATE_MINSTREL,
.node_init = ath_rate_node_init,
.node_cleanup = ath_rate_node_cleanup,
.findrate = ath_rate_findrate,
.get_mrr = ath_rate_get_mrr,
.tx_complete = ath_rate_tx_complete,
.newassoc = ath_rate_newassoc,
.newstate = ath_rate_newstate,
.attach = ath_rate_attach,
.detach = ath_rate_detach,
.dynamic_proc_register = ath_rate_dynamic_proc_register,
};
MODULE_AUTHOR("John Bicket/Derek Smithies");
MODULE_DESCRIPTION("Minstrel Rate bit-rate selection algorithm for Atheros devices");
#ifdef MODULE_VERSION
MODULE_VERSION(RELEASE_VERSION);
#endif
#ifdef MODULE_LICENSE
MODULE_LICENSE("Dual BSD/GPL");
#endif
static int __init ath_rate_minstrel_init(void)
{
/* Debugging output - disabled as noisy. */
#if 0
printk(KERN_INFO "%s: look around rate set to %d%%\n",
dev_info, ath_lookaround_rate);
printk(KERN_INFO "%s: EWMA rolloff level set to %d%%\n",
dev_info, ath_ewma_level);
printk(KERN_INFO "%s: max segment size in the MRR set "
"to %d us\n", dev_info, ath_segment_size);
#endif
return ieee80211_rate_register(&ath_rate_ops);
}
module_init(ath_rate_minstrel_init);
static void __exit ath_rate_minstrel_exit(void)
{
ieee80211_rate_unregister(&ath_rate_ops);
}
module_exit(ath_rate_minstrel_exit);
/* The comment below is magic for those who use emacs to edit this file. */
/* With the comment below, the tab key does auto indent to 8 spaces. */
/*
* Local Variables:
* mode:c
* c-file-style:linux
* c-basic-offset:8
* End:
*/
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