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madwifi/ath_rate/minstrel/minstrel.c
proski cf2afadc08 Fix sample and minstrel algorithms for AR5416 
Use correct shifts for the rate data.  Remove excessive debug statements
that would have to be extended even further to deal with AR5416.

The code has been taken from the FreeBSD driver.  The original coding
style has been preserved.


git-svn-id: http://madwifi-project.org/svn/madwifi/trunk@4015 0192ed92-7a03-0410-a25b-9323aeb14dbd
2009-04-28 05:59:25 +00:00

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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->num_rates <= 0) {
DPRINTF(sc, "%s: no rates for " MAC_FMT "\n",
dev_info,
MAC_ADDR(an->an_node.ni_macaddr));
memset(mrr, 0, sizeof(struct ieee80211_mrr));
return;
}
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, hwrate0;
int rate1, tries1, ndx1, hwrate1;
int rate2, tries2, ndx2, hwrate2;
int rate3, tries3, ndx3, hwrate3;
/* 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 */
if (sc->sc_ah->ah_magic != 0x20065416) {
hwrate0 = MS(ds->ds_ctl3, AR_XmitRate0);
hwrate1 = MS(ds->ds_ctl3, AR_XmitRate1);
hwrate2 = MS(ds->ds_ctl3, AR_XmitRate2);
hwrate3 = MS(ds->ds_ctl3, AR_XmitRate3);
} else {
hwrate0 = MS(ds->ds_ctl3, AR5416_XmitRate0);
hwrate1 = MS(ds->ds_ctl3, AR5416_XmitRate1);
hwrate2 = MS(ds->ds_ctl3, AR5416_XmitRate2);
hwrate3 = MS(ds->ds_ctl3, AR5416_XmitRate3);
}
rate0 = sc->sc_hwmap[hwrate0].ieeerate;
tries0 = MS(ds->ds_ctl2, AR_XmitDataTries0);
ndx0 = rate_to_ndx(sn, rate0);
rate1 = sc->sc_hwmap[hwrate1].ieeerate;
tries1 = MS(ds->ds_ctl2, AR_XmitDataTries1);
ndx1 = rate_to_ndx(sn, rate1);
rate2 = sc->sc_hwmap[hwrate2].ieeerate;
tries2 = MS(ds->ds_ctl2, AR_XmitDataTries2);
ndx2 = rate_to_ndx(sn, rate2);
rate3 = sc->sc_hwmap[hwrate3].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(netdev_priv(ni->ni_ic->ic_dev), 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(netdev_priv(ic->ic_dev),
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 = netdev_priv(vap->iv_ic->ic_dev);
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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