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freebsd-nq/sys/dev/ath/ath_rate/sample/sample.h
Adrian Chadd eb6f0de09d Introduce TX aggregation and software TX queue management 
for Atheros AR5416 and later wireless devices.

This is a very large commit - the complete history can be
found in the user/adrian/if_ath_tx branch.

Legacy (ie, pre-AR5416) devices also use the per-software
TXQ support and (in theory) can support non-aggregation
ADDBA sessions. However, the net80211 stack doesn't currently
support this.

In summary:

TX path:

* queued frames normally go onto a per-TID, per-node queue
* some special frames (eg ADDBA control frames) are thrown
  directly onto the relevant hardware queue so they can
  go out before any software queued frames are queued.
* Add methods to create, suspend, resume and tear down an
  aggregation session.
* Add in software retransmission of both normal and aggregate
  frames.
* Add in completion handling of aggregate frames, including
  parsing the block ack bitmap provided by the hardware.
* Write an aggregation function which can assemble frames into
  an aggregate based on the selected rate control and channel
  configuration.
* The per-TID queues are locked based on their target hardware
  TX queue. This matches what ath9k/atheros does, and thus
  simplified porting over some of the aggregation logic.
* When doing TX aggregation, stick the sequence number allocation
  in the TX path rather than net80211 TX path, and protect it
  by the TXQ lock.

Rate control:

* Delay rate control selection until the frame is about to
  be queued to the hardware, so retried frames can have their
  rate control choices changed. Frames with a static rate
  control selection have that applied before each TX, just
  to simplify the TX path (ie, not have "static" and "dynamic"
  rate control special cased.)
* Teach ath_rate_sample about aggregates - both completion and
  errors.
* Add an EWMA for tracking what the current "good" MCS rate is
  based on failure rates.

Misc:

* Introduce a bunch of dirty hacks and workarounds so TID mapping
  and net80211 frame inspection can be kept out of the net80211
  layer. Because of the way this code works (and it's from Atheros
  and Linux ath9k), there is a consistent, 1:1 mapping between
  TID and AC. So we need to ensure that frames going to a specific
  TID will _always_ end up on the right AC, and vice versa, or the
  completion/locking will simply get very confused. I plan on
  addressing this mess in the future.

Known issues:

* There is no BAR frame transmission just yet. A whole lot of
  tidying up needs to occur before BAR frame TX can occur in the
  "correct" place - ie, once the TID TX queue has been drained.

* Interface reset/purge/etc results in frames in the TX and RX
  queues being removed. This creates holes in the sequence numbers
  being assigned and the TX/RX AMPDU code (on either side) just
  hangs.

* There's no filtered frame support at the present moment, so
  stations going into power saving mode will simply have a number
  of frames dropped - likely resulting in a traffic "hang".

* Raw frame TX is going to just not function with 11n aggregation.
  Likely this needs to be modified to always override the sequence
  number if the frame is going into an aggregation session.
  However, general raw frame injection currently doesn't work in
  general in net80211, so let's just ignore this for now until
  this is sorted out.

* HT protection is just not implemented and won't be until the above
  is sorted out. In addition, the AR5416 has issues RTS protecting
  large aggregates (anything >8k), so the work around needs to be
  ported and tested. Thus, this will be put on hold until the above
  work is complete.

* The rate control module 'sample' is the only currently supported
  module; onoe/amrr haven't been tested and have likely bit rotted
  a little. I'll follow up with some commits to make them work again
  for non-11n rates, but they won't be updated to handle 11n and
  aggregation. If someone wishes to do so then they're welcome to
  send along patches.

* .. and "sample" doesn't really do a good job of 11n TX. Specifically,
  the metrics used (packet TX time and failure/success rates) isn't as
  useful for 11n. It's likely that it should be extended to take into
  account the aggregate throughput possible and then choose a rate
  which maximises that. Ie, it may be acceptable for a higher MCS rate
  with a higher failure to be used if it gives a more acceptable
  throughput/latency then a lower MCS rate @ a lower error rate.
  Again, patches will be gratefully accepted.

Because of this, ATH_ENABLE_11N is still not enabled by default.

Sponsored by:	Hobnob, Inc.
Obtained from:	Linux, Atheros
2011-11-08 22:43:13 +00:00

227 lines
6.7 KiB
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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.
*
* $FreeBSD$
*/
/*
* Defintions for the Atheros Wireless LAN controller driver.
*/
#ifndef _DEV_ATH_RATE_SAMPLE_H
#define _DEV_ATH_RATE_SAMPLE_H
/* per-device state */
struct sample_softc {
struct ath_ratectrl arc; /* base class */
int smoothing_rate; /* ewma percentage [0..99] */
int smoothing_minpackets;
int sample_rate; /* %time to try different tx rates */
int max_successive_failures;
int stale_failure_timeout; /* how long to honor max_successive_failures */
int min_switch; /* min time between rate changes */
int min_good_pct; /* min good percentage for a rate to be considered */
};
#define ATH_SOFTC_SAMPLE(sc) ((struct sample_softc *)sc->sc_rc)
struct rate_stats {
unsigned average_tx_time;
int successive_failures;
uint64_t tries;
uint64_t total_packets; /* pkts total since assoc */
uint64_t packets_acked; /* pkts acked since assoc */
int ewma_pct; /* EWMA percentage */
unsigned perfect_tx_time; /* transmit time for 0 retries */
int last_tx;
};
struct txschedule {
uint8_t t0, r0; /* series 0: tries, rate code */
uint8_t t1, r1; /* series 1: tries, rate code */
uint8_t t2, r2; /* series 2: tries, rate code */
uint8_t t3, r3; /* series 3: tries, rate code */
};
/*
* for now, we track performance for three different packet
* size buckets
*/
#define NUM_PACKET_SIZE_BINS 2
/* per-node state */
struct sample_node {
int static_rix; /* rate index of fixed tx rate */
#define SAMPLE_MAXRATES 32 /* NB: corresponds to hal info[32] */
uint32_t ratemask; /* bit mask of valid rate indices */
const struct txschedule *sched; /* tx schedule table */
struct rate_stats stats[NUM_PACKET_SIZE_BINS][SAMPLE_MAXRATES];
int last_sample_rix[NUM_PACKET_SIZE_BINS];
int current_sample_rix[NUM_PACKET_SIZE_BINS];
int packets_sent[NUM_PACKET_SIZE_BINS];
int current_rix[NUM_PACKET_SIZE_BINS];
int packets_since_switch[NUM_PACKET_SIZE_BINS];
unsigned ticks_since_switch[NUM_PACKET_SIZE_BINS];
int packets_since_sample[NUM_PACKET_SIZE_BINS];
unsigned sample_tt[NUM_PACKET_SIZE_BINS];
};
#define ATH_NODE_SAMPLE(an) ((struct sample_node *)&(an)[1])
#define IS_RATE_DEFINED(sn, rix) (((sn)->ratemask & (1<<(rix))) != 0)
#ifndef MIN
#define MIN(a,b) ((a) < (b) ? (a) : (b))
#endif
#ifndef MAX
#define MAX(a,b) ((a) > (b) ? (a) : (b))
#endif
#define WIFI_CW_MIN 31
#define WIFI_CW_MAX 1023
/*
* 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, int is_ht40)
{
const HAL_RATE_TABLE *rt = sc->sc_currates;
struct ifnet *ifp = sc->sc_ifp;
struct ieee80211com *ic = ifp->if_l2com;
int rts, cts;
unsigned t_slot = 20;
unsigned t_difs = 50;
unsigned t_sifs = 10;
int tt = 0;
int x = 0;
int cw = WIFI_CW_MIN;
int cix;
KASSERT(rt != NULL, ("no rate table, mode %u", sc->sc_curmode));
if (rix >= rt->rateCount) {
printf("bogus rix %d, max %u, mode %u\n",
rix, rt->rateCount, sc->sc_curmode);
return 0;
}
cix = rt->info[rix].controlRate;
/*
* 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:
t_slot = 9;
t_sifs = 16;
t_difs = 28;
/* fall through */
case IEEE80211_T_TURBO:
t_slot = 9;
t_sifs = 8;
t_difs = 28;
break;
case IEEE80211_T_HT:
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;
}
rts = cts = 0;
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 /*length > ic->ic_rtsthreshold */) {
rts = 1;
}
if (rts || cts) {
int ctsrate;
int ctsduration = 0;
/* NB: this is intentionally not a runtime check */
KASSERT(cix < rt->rateCount,
("bogus cix %d, max %u, mode %u\n", cix, rt->rateCount,
sc->sc_curmode));
ctsrate = rt->info[cix].rateCode | rt->info[cix].shortPreamble;
if (rts) /* SIFS + CTS */
ctsduration += rt->info[cix].spAckDuration;
/* XXX assumes short preamble */
ctsduration += ath_hal_pkt_txtime(sc->sc_ah, rt, length, rix,
is_ht40, 0);
if (cts) /* SIFS + ACK */
ctsduration += rt->info[cix].spAckDuration;
tt += (short_retries + 1) * ctsduration;
}
tt += t_difs;
/* XXX assumes short preamble */
tt += (long_retries+1)*ath_hal_pkt_txtime(sc->sc_ah, rt, length, rix,
is_ht40, 0);
tt += (long_retries+1)*(t_sifs + rt->info[rix].spAckDuration);
for (x = 0; x <= short_retries + long_retries; x++) {
cw = MIN(WIFI_CW_MAX, (cw + 1) * 2);
tt += (t_slot * cw/2);
}
return tt;
}
#endif /* _DEV_ATH_RATE_SAMPLE_H */
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