linux/net/mac80211/rc80211_pid_algo.c

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/*
* 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 cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#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);
}