mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-28 20:02:17 +00:00
![Rusty Russell](/assets/img/avatar_default.png)
DaveM said: Please, this kind of stuff rots forever and not using bool properly drives me crazy. Joe Perches <joe@perches.com> gave me the spatch script: @@ bool b; @@ -b = 0 +b = false @@ bool b; @@ -b = 1 +b = true I merely installed coccinelle, read the documentation and took credit. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: David S. Miller <davem@davemloft.net>
477 lines
15 KiB
C
477 lines
15 KiB
C
/*
|
|
* Copyright 2002-2005, Instant802 Networks, Inc.
|
|
* Copyright 2005, Devicescape Software, Inc.
|
|
* Copyright 2007, Mattias Nissler <mattias.nissler@gmx.de>
|
|
* Copyright 2007-2008, 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.
|
|
*/
|
|
|
|
#include <linux/netdevice.h>
|
|
#include <linux/types.h>
|
|
#include <linux/skbuff.h>
|
|
#include <linux/debugfs.h>
|
|
#include <linux/slab.h>
|
|
#include <net/mac80211.h>
|
|
#include "rate.h"
|
|
#include "mesh.h"
|
|
#include "rc80211_pid.h"
|
|
|
|
|
|
/* This is an implementation of a TX rate control algorithm that uses a PID
|
|
* controller. Given a target failed frames rate, the controller decides about
|
|
* TX rate changes to meet the target failed frames rate.
|
|
*
|
|
* The controller basically computes the following:
|
|
*
|
|
* adj = CP * err + CI * err_avg + CD * (err - last_err) * (1 + sharpening)
|
|
*
|
|
* where
|
|
* adj adjustment value that is used to switch TX rate (see below)
|
|
* err current error: target vs. current failed frames percentage
|
|
* last_err last error
|
|
* err_avg average (i.e. poor man's integral) of recent errors
|
|
* sharpening non-zero when fast response is needed (i.e. right after
|
|
* association or no frames sent for a long time), heading
|
|
* to zero over time
|
|
* CP Proportional coefficient
|
|
* CI Integral coefficient
|
|
* CD Derivative coefficient
|
|
*
|
|
* CP, CI, CD are subject to careful tuning.
|
|
*
|
|
* The integral component uses a exponential moving average approach instead of
|
|
* an actual sliding window. The advantage is that we don't need to keep an
|
|
* array of the last N error values and computation is easier.
|
|
*
|
|
* Once we have the adj value, we map it to a rate by means of a learning
|
|
* algorithm. This algorithm keeps the state of the percentual failed frames
|
|
* difference between rates. The behaviour of the lowest available rate is kept
|
|
* as a reference value, and every time we switch between two rates, we compute
|
|
* the difference between the failed frames each rate exhibited. By doing so,
|
|
* we compare behaviours which different rates exhibited in adjacent timeslices,
|
|
* thus the comparison is minimally affected by external conditions. This
|
|
* difference gets propagated to the whole set of measurements, so that the
|
|
* reference is always the same. Periodically, we normalize this set so that
|
|
* recent events weigh the most. By comparing the adj value with this set, we
|
|
* avoid pejorative switches to lower rates and allow for switches to higher
|
|
* rates if they behaved well.
|
|
*
|
|
* Note that for the computations we use a fixed-point representation to avoid
|
|
* floating point arithmetic. Hence, all values are shifted left by
|
|
* RC_PID_ARITH_SHIFT.
|
|
*/
|
|
|
|
|
|
/* Adjust the rate while ensuring that we won't switch to a lower rate if it
|
|
* exhibited a worse failed frames behaviour and we'll choose the highest rate
|
|
* whose failed frames behaviour is not worse than the one of the original rate
|
|
* target. While at it, check that the new rate is valid. */
|
|
static void rate_control_pid_adjust_rate(struct ieee80211_supported_band *sband,
|
|
struct ieee80211_sta *sta,
|
|
struct rc_pid_sta_info *spinfo, int adj,
|
|
struct rc_pid_rateinfo *rinfo)
|
|
{
|
|
int cur_sorted, new_sorted, probe, tmp, n_bitrates, band;
|
|
int cur = spinfo->txrate_idx;
|
|
|
|
band = sband->band;
|
|
n_bitrates = sband->n_bitrates;
|
|
|
|
/* Map passed arguments to sorted values. */
|
|
cur_sorted = rinfo[cur].rev_index;
|
|
new_sorted = cur_sorted + adj;
|
|
|
|
/* Check limits. */
|
|
if (new_sorted < 0)
|
|
new_sorted = rinfo[0].rev_index;
|
|
else if (new_sorted >= n_bitrates)
|
|
new_sorted = rinfo[n_bitrates - 1].rev_index;
|
|
|
|
tmp = new_sorted;
|
|
|
|
if (adj < 0) {
|
|
/* Ensure that the rate decrease isn't disadvantageous. */
|
|
for (probe = cur_sorted; probe >= new_sorted; probe--)
|
|
if (rinfo[probe].diff <= rinfo[cur_sorted].diff &&
|
|
rate_supported(sta, band, rinfo[probe].index))
|
|
tmp = probe;
|
|
} else {
|
|
/* Look for rate increase with zero (or below) cost. */
|
|
for (probe = new_sorted + 1; probe < n_bitrates; probe++)
|
|
if (rinfo[probe].diff <= rinfo[new_sorted].diff &&
|
|
rate_supported(sta, band, rinfo[probe].index))
|
|
tmp = probe;
|
|
}
|
|
|
|
/* Fit the rate found to the nearest supported rate. */
|
|
do {
|
|
if (rate_supported(sta, band, rinfo[tmp].index)) {
|
|
spinfo->txrate_idx = rinfo[tmp].index;
|
|
break;
|
|
}
|
|
if (adj < 0)
|
|
tmp--;
|
|
else
|
|
tmp++;
|
|
} while (tmp < n_bitrates && tmp >= 0);
|
|
|
|
#ifdef CONFIG_MAC80211_DEBUGFS
|
|
rate_control_pid_event_rate_change(&spinfo->events,
|
|
spinfo->txrate_idx,
|
|
sband->bitrates[spinfo->txrate_idx].bitrate);
|
|
#endif
|
|
}
|
|
|
|
/* Normalize the failed frames per-rate differences. */
|
|
static void rate_control_pid_normalize(struct rc_pid_info *pinfo, int l)
|
|
{
|
|
int i, norm_offset = pinfo->norm_offset;
|
|
struct rc_pid_rateinfo *r = pinfo->rinfo;
|
|
|
|
if (r[0].diff > norm_offset)
|
|
r[0].diff -= norm_offset;
|
|
else if (r[0].diff < -norm_offset)
|
|
r[0].diff += norm_offset;
|
|
for (i = 0; i < l - 1; i++)
|
|
if (r[i + 1].diff > r[i].diff + norm_offset)
|
|
r[i + 1].diff -= norm_offset;
|
|
else if (r[i + 1].diff <= r[i].diff)
|
|
r[i + 1].diff += norm_offset;
|
|
}
|
|
|
|
static void rate_control_pid_sample(struct rc_pid_info *pinfo,
|
|
struct ieee80211_supported_band *sband,
|
|
struct ieee80211_sta *sta,
|
|
struct rc_pid_sta_info *spinfo)
|
|
{
|
|
struct rc_pid_rateinfo *rinfo = pinfo->rinfo;
|
|
u32 pf;
|
|
s32 err_avg;
|
|
u32 err_prop;
|
|
u32 err_int;
|
|
u32 err_der;
|
|
int adj, i, j, tmp;
|
|
unsigned long period;
|
|
|
|
/* In case nothing happened during the previous control interval, turn
|
|
* the sharpening factor on. */
|
|
period = msecs_to_jiffies(pinfo->sampling_period);
|
|
if (jiffies - spinfo->last_sample > 2 * period)
|
|
spinfo->sharp_cnt = pinfo->sharpen_duration;
|
|
|
|
spinfo->last_sample = jiffies;
|
|
|
|
/* This should never happen, but in case, we assume the old sample is
|
|
* still a good measurement and copy it. */
|
|
if (unlikely(spinfo->tx_num_xmit == 0))
|
|
pf = spinfo->last_pf;
|
|
else
|
|
pf = spinfo->tx_num_failed * 100 / spinfo->tx_num_xmit;
|
|
|
|
spinfo->tx_num_xmit = 0;
|
|
spinfo->tx_num_failed = 0;
|
|
|
|
/* If we just switched rate, update the rate behaviour info. */
|
|
if (pinfo->oldrate != spinfo->txrate_idx) {
|
|
|
|
i = rinfo[pinfo->oldrate].rev_index;
|
|
j = rinfo[spinfo->txrate_idx].rev_index;
|
|
|
|
tmp = (pf - spinfo->last_pf);
|
|
tmp = RC_PID_DO_ARITH_RIGHT_SHIFT(tmp, RC_PID_ARITH_SHIFT);
|
|
|
|
rinfo[j].diff = rinfo[i].diff + tmp;
|
|
pinfo->oldrate = spinfo->txrate_idx;
|
|
}
|
|
rate_control_pid_normalize(pinfo, sband->n_bitrates);
|
|
|
|
/* Compute the proportional, integral and derivative errors. */
|
|
err_prop = (pinfo->target - pf) << RC_PID_ARITH_SHIFT;
|
|
|
|
err_avg = spinfo->err_avg_sc >> pinfo->smoothing_shift;
|
|
spinfo->err_avg_sc = spinfo->err_avg_sc - err_avg + err_prop;
|
|
err_int = spinfo->err_avg_sc >> pinfo->smoothing_shift;
|
|
|
|
err_der = (pf - spinfo->last_pf) *
|
|
(1 + pinfo->sharpen_factor * spinfo->sharp_cnt);
|
|
spinfo->last_pf = pf;
|
|
if (spinfo->sharp_cnt)
|
|
spinfo->sharp_cnt--;
|
|
|
|
#ifdef CONFIG_MAC80211_DEBUGFS
|
|
rate_control_pid_event_pf_sample(&spinfo->events, pf, err_prop, err_int,
|
|
err_der);
|
|
#endif
|
|
|
|
/* Compute the controller output. */
|
|
adj = (err_prop * pinfo->coeff_p + err_int * pinfo->coeff_i
|
|
+ err_der * pinfo->coeff_d);
|
|
adj = RC_PID_DO_ARITH_RIGHT_SHIFT(adj, 2 * RC_PID_ARITH_SHIFT);
|
|
|
|
/* Change rate. */
|
|
if (adj)
|
|
rate_control_pid_adjust_rate(sband, sta, spinfo, adj, rinfo);
|
|
}
|
|
|
|
static void rate_control_pid_tx_status(void *priv, struct ieee80211_supported_band *sband,
|
|
struct ieee80211_sta *sta, void *priv_sta,
|
|
struct sk_buff *skb)
|
|
{
|
|
struct rc_pid_info *pinfo = priv;
|
|
struct rc_pid_sta_info *spinfo = priv_sta;
|
|
unsigned long period;
|
|
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
|
|
|
|
if (!spinfo)
|
|
return;
|
|
|
|
/* Ignore all frames that were sent with a different rate than the rate
|
|
* we currently advise mac80211 to use. */
|
|
if (info->status.rates[0].idx != spinfo->txrate_idx)
|
|
return;
|
|
|
|
spinfo->tx_num_xmit++;
|
|
|
|
#ifdef CONFIG_MAC80211_DEBUGFS
|
|
rate_control_pid_event_tx_status(&spinfo->events, info);
|
|
#endif
|
|
|
|
/* We count frames that totally failed to be transmitted as two bad
|
|
* frames, those that made it out but had some retries as one good and
|
|
* one bad frame. */
|
|
if (!(info->flags & IEEE80211_TX_STAT_ACK)) {
|
|
spinfo->tx_num_failed += 2;
|
|
spinfo->tx_num_xmit++;
|
|
} else if (info->status.rates[0].count > 1) {
|
|
spinfo->tx_num_failed++;
|
|
spinfo->tx_num_xmit++;
|
|
}
|
|
|
|
/* Update PID controller state. */
|
|
period = msecs_to_jiffies(pinfo->sampling_period);
|
|
if (time_after(jiffies, spinfo->last_sample + period))
|
|
rate_control_pid_sample(pinfo, sband, sta, spinfo);
|
|
}
|
|
|
|
static void
|
|
rate_control_pid_get_rate(void *priv, struct ieee80211_sta *sta,
|
|
void *priv_sta,
|
|
struct ieee80211_tx_rate_control *txrc)
|
|
{
|
|
struct sk_buff *skb = txrc->skb;
|
|
struct ieee80211_supported_band *sband = txrc->sband;
|
|
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
|
|
struct rc_pid_sta_info *spinfo = priv_sta;
|
|
int rateidx;
|
|
|
|
if (txrc->rts)
|
|
info->control.rates[0].count =
|
|
txrc->hw->conf.long_frame_max_tx_count;
|
|
else
|
|
info->control.rates[0].count =
|
|
txrc->hw->conf.short_frame_max_tx_count;
|
|
|
|
/* Send management frames and NO_ACK data using lowest rate. */
|
|
if (rate_control_send_low(sta, priv_sta, txrc))
|
|
return;
|
|
|
|
rateidx = spinfo->txrate_idx;
|
|
|
|
if (rateidx >= sband->n_bitrates)
|
|
rateidx = sband->n_bitrates - 1;
|
|
|
|
info->control.rates[0].idx = rateidx;
|
|
|
|
#ifdef CONFIG_MAC80211_DEBUGFS
|
|
rate_control_pid_event_tx_rate(&spinfo->events,
|
|
rateidx, sband->bitrates[rateidx].bitrate);
|
|
#endif
|
|
}
|
|
|
|
static void
|
|
rate_control_pid_rate_init(void *priv, struct ieee80211_supported_band *sband,
|
|
struct ieee80211_sta *sta, void *priv_sta)
|
|
{
|
|
struct rc_pid_sta_info *spinfo = priv_sta;
|
|
struct rc_pid_info *pinfo = priv;
|
|
struct rc_pid_rateinfo *rinfo = pinfo->rinfo;
|
|
int i, j, tmp;
|
|
bool s;
|
|
|
|
/* TODO: This routine should consider using RSSI from previous packets
|
|
* as we need to have IEEE 802.1X auth succeed immediately after assoc..
|
|
* Until that method is implemented, we will use the lowest supported
|
|
* rate as a workaround. */
|
|
|
|
/* Sort the rates. This is optimized for the most common case (i.e.
|
|
* almost-sorted CCK+OFDM rates). Kind of bubble-sort with reversed
|
|
* mapping too. */
|
|
for (i = 0; i < sband->n_bitrates; i++) {
|
|
rinfo[i].index = i;
|
|
rinfo[i].rev_index = i;
|
|
if (RC_PID_FAST_START)
|
|
rinfo[i].diff = 0;
|
|
else
|
|
rinfo[i].diff = i * pinfo->norm_offset;
|
|
}
|
|
for (i = 1; i < sband->n_bitrates; i++) {
|
|
s = false;
|
|
for (j = 0; j < sband->n_bitrates - i; j++)
|
|
if (unlikely(sband->bitrates[rinfo[j].index].bitrate >
|
|
sband->bitrates[rinfo[j + 1].index].bitrate)) {
|
|
tmp = rinfo[j].index;
|
|
rinfo[j].index = rinfo[j + 1].index;
|
|
rinfo[j + 1].index = tmp;
|
|
rinfo[rinfo[j].index].rev_index = j;
|
|
rinfo[rinfo[j + 1].index].rev_index = j + 1;
|
|
s = true;
|
|
}
|
|
if (!s)
|
|
break;
|
|
}
|
|
|
|
spinfo->txrate_idx = rate_lowest_index(sband, sta);
|
|
}
|
|
|
|
static void *rate_control_pid_alloc(struct ieee80211_hw *hw,
|
|
struct dentry *debugfsdir)
|
|
{
|
|
struct rc_pid_info *pinfo;
|
|
struct rc_pid_rateinfo *rinfo;
|
|
struct ieee80211_supported_band *sband;
|
|
int i, max_rates = 0;
|
|
#ifdef CONFIG_MAC80211_DEBUGFS
|
|
struct rc_pid_debugfs_entries *de;
|
|
#endif
|
|
|
|
pinfo = kmalloc(sizeof(*pinfo), GFP_ATOMIC);
|
|
if (!pinfo)
|
|
return NULL;
|
|
|
|
for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
|
|
sband = hw->wiphy->bands[i];
|
|
if (sband && sband->n_bitrates > max_rates)
|
|
max_rates = sband->n_bitrates;
|
|
}
|
|
|
|
rinfo = kmalloc(sizeof(*rinfo) * max_rates, GFP_ATOMIC);
|
|
if (!rinfo) {
|
|
kfree(pinfo);
|
|
return NULL;
|
|
}
|
|
|
|
pinfo->target = RC_PID_TARGET_PF;
|
|
pinfo->sampling_period = RC_PID_INTERVAL;
|
|
pinfo->coeff_p = RC_PID_COEFF_P;
|
|
pinfo->coeff_i = RC_PID_COEFF_I;
|
|
pinfo->coeff_d = RC_PID_COEFF_D;
|
|
pinfo->smoothing_shift = RC_PID_SMOOTHING_SHIFT;
|
|
pinfo->sharpen_factor = RC_PID_SHARPENING_FACTOR;
|
|
pinfo->sharpen_duration = RC_PID_SHARPENING_DURATION;
|
|
pinfo->norm_offset = RC_PID_NORM_OFFSET;
|
|
pinfo->rinfo = rinfo;
|
|
pinfo->oldrate = 0;
|
|
|
|
#ifdef CONFIG_MAC80211_DEBUGFS
|
|
de = &pinfo->dentries;
|
|
de->target = debugfs_create_u32("target_pf", S_IRUSR | S_IWUSR,
|
|
debugfsdir, &pinfo->target);
|
|
de->sampling_period = debugfs_create_u32("sampling_period",
|
|
S_IRUSR | S_IWUSR, debugfsdir,
|
|
&pinfo->sampling_period);
|
|
de->coeff_p = debugfs_create_u32("coeff_p", S_IRUSR | S_IWUSR,
|
|
debugfsdir, (u32 *)&pinfo->coeff_p);
|
|
de->coeff_i = debugfs_create_u32("coeff_i", S_IRUSR | S_IWUSR,
|
|
debugfsdir, (u32 *)&pinfo->coeff_i);
|
|
de->coeff_d = debugfs_create_u32("coeff_d", S_IRUSR | S_IWUSR,
|
|
debugfsdir, (u32 *)&pinfo->coeff_d);
|
|
de->smoothing_shift = debugfs_create_u32("smoothing_shift",
|
|
S_IRUSR | S_IWUSR, debugfsdir,
|
|
&pinfo->smoothing_shift);
|
|
de->sharpen_factor = debugfs_create_u32("sharpen_factor",
|
|
S_IRUSR | S_IWUSR, debugfsdir,
|
|
&pinfo->sharpen_factor);
|
|
de->sharpen_duration = debugfs_create_u32("sharpen_duration",
|
|
S_IRUSR | S_IWUSR, debugfsdir,
|
|
&pinfo->sharpen_duration);
|
|
de->norm_offset = debugfs_create_u32("norm_offset",
|
|
S_IRUSR | S_IWUSR, debugfsdir,
|
|
&pinfo->norm_offset);
|
|
#endif
|
|
|
|
return pinfo;
|
|
}
|
|
|
|
static void rate_control_pid_free(void *priv)
|
|
{
|
|
struct rc_pid_info *pinfo = priv;
|
|
#ifdef CONFIG_MAC80211_DEBUGFS
|
|
struct rc_pid_debugfs_entries *de = &pinfo->dentries;
|
|
|
|
debugfs_remove(de->norm_offset);
|
|
debugfs_remove(de->sharpen_duration);
|
|
debugfs_remove(de->sharpen_factor);
|
|
debugfs_remove(de->smoothing_shift);
|
|
debugfs_remove(de->coeff_d);
|
|
debugfs_remove(de->coeff_i);
|
|
debugfs_remove(de->coeff_p);
|
|
debugfs_remove(de->sampling_period);
|
|
debugfs_remove(de->target);
|
|
#endif
|
|
|
|
kfree(pinfo->rinfo);
|
|
kfree(pinfo);
|
|
}
|
|
|
|
static void *rate_control_pid_alloc_sta(void *priv, struct ieee80211_sta *sta,
|
|
gfp_t gfp)
|
|
{
|
|
struct rc_pid_sta_info *spinfo;
|
|
|
|
spinfo = kzalloc(sizeof(*spinfo), gfp);
|
|
if (spinfo == NULL)
|
|
return NULL;
|
|
|
|
spinfo->last_sample = jiffies;
|
|
|
|
#ifdef CONFIG_MAC80211_DEBUGFS
|
|
spin_lock_init(&spinfo->events.lock);
|
|
init_waitqueue_head(&spinfo->events.waitqueue);
|
|
#endif
|
|
|
|
return spinfo;
|
|
}
|
|
|
|
static void rate_control_pid_free_sta(void *priv, struct ieee80211_sta *sta,
|
|
void *priv_sta)
|
|
{
|
|
kfree(priv_sta);
|
|
}
|
|
|
|
static struct rate_control_ops mac80211_rcpid = {
|
|
.name = "pid",
|
|
.tx_status = rate_control_pid_tx_status,
|
|
.get_rate = rate_control_pid_get_rate,
|
|
.rate_init = rate_control_pid_rate_init,
|
|
.alloc = rate_control_pid_alloc,
|
|
.free = rate_control_pid_free,
|
|
.alloc_sta = rate_control_pid_alloc_sta,
|
|
.free_sta = rate_control_pid_free_sta,
|
|
#ifdef CONFIG_MAC80211_DEBUGFS
|
|
.add_sta_debugfs = rate_control_pid_add_sta_debugfs,
|
|
.remove_sta_debugfs = rate_control_pid_remove_sta_debugfs,
|
|
#endif
|
|
};
|
|
|
|
int __init rc80211_pid_init(void)
|
|
{
|
|
return ieee80211_rate_control_register(&mac80211_rcpid);
|
|
}
|
|
|
|
void rc80211_pid_exit(void)
|
|
{
|
|
ieee80211_rate_control_unregister(&mac80211_rcpid);
|
|
}
|