Add get_expected_throughput() API to mac80211 so that each
driver can implement its own version based on the RC
algorithm they are using (might be using an HW RC algo).
The API returns a value expressed in Kbps.
Also, add the new get_expected_throughput() member
to the rate_control_ops structure in order to be
able to query the RC algorithm (this patch provides an
implementation of this API for both minstrel and
minstrel_ht).
The related member in the station_info object is now
filled accordingly when dumping a station.
Cc: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Antonio and I were looking over this code and some things
didn't immediately make sense, so we came up with two small
clarifications.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
The sample table is initialized only once at module start, so
is really __read_mostly. Additionally, the code to init it can
be marked __init since it will never be needed again, it is
likely automatically inlined into the __init function already
by the compiler, so this doesn't really make a difference.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Change the code to allow making all the rate control ops
const, nothing ever needs to change them. Also change all
drivers to make use of this and mark the ops const.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Fix a number of different checkpatch errors.
Signed-off-by: Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
ATM minstrel_ht does not check whether a sampling rate is supported.
Unsupported rates attempts can trigger when there are holes in bitfields
of supported MCSes belonging to the same group (e.g many devices are
MCS32 capable without MCS33->39 capable, also we systematically have a
hole for CCK rates).
Drop any attempts to sample unsupported rates, as suggested by Felix.
This is not a problem in minstrel which fills a per STA sample table
with only supported rates (though only at init).
Signed-off-by: Karl Beldan <karl.beldan@rivierawaves.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
ATM, only the first array value returned by get_random_bytes is used.
This change moves the call to get_random_bytes from the nested loop it
is in to its parent.
While at it, replace get_random_bytes with prandom_bytes since PRNs are
way enough for the selection process.
After this, minstrel_ht reclaims 80 PR-bytes instead of 640 R-bytes.
minstrels use sample tables to probe different rates in a randomized
manner.
minstrel_ht inits one single sample table upon registration (during
subsys_initcalls) and minstrel uses one per STA addition in minstrel.
Signed-off-by: Karl Beldan <karl.beldan@rivierawaves.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Consecutive MCSes in [8*(NSS-1)->8*NSS[ have the same number NSS of
streams (except for MCS32 which is mishandled ATM).
ATM minstrel_ht uses MCS_GROUP_RATES in place of this 8 modulus.
This change replaces such occurences and by doing so allows for different
values of MCS_GROUP_RATES (e.g to cope with VHT MCS8,9).
Signed-off-by: Karl Beldan <karl.beldan@rivierawaves.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Commit 3e8b1eb "mac80211/minstrel_ht: improve rate selection stability"
introduced a local capped prob in minstrel_ht_calc_tp but omitted to use
it to compute the per rate throughput.
Signed-off-by: Karl Beldan <karl.beldan@rivierawaves.com>
Cc: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
When initializing rates selections starting indexes upon stats update,
the minstrel_sta->max_* rates should be 'group * MCS_GROUP_RATES + i'
not 'i'. This affects settings where one of the peers does not support
any of the rates of the group 0 (i.e. when ht_cap.mcs.rx_mask[0] == 0).
Signed-off-by: Karl Beldan <karl.beldan@rivierawaves.com>
Acked-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Do not override max_tp_rate, max_tp_rate2 and max_prob_rate configured
according to fixed_rate in minstrel_ht_update_stats throughput computation
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>
Acked-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Sujith reports that my commit af61a16518
("mac80211: add control port protocol TX control flag") broke ath9k
(aggregation). The reason is that I made minstrel_ht use the flag in
the TX status path, where it can have been overwritten by the driver.
Since we have no more space in info->flags, revert that part of the
change for now, until we can reshuffle the flags or so.
Reported-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
brcm80211 cannot handle sending frames with CCK rates as part of an
A-MPDU session. Other drivers may have issues too. Set the flag in all
drivers that have been tested with CCK rates.
This fixes a reported brcmsmac regression introduced in
commit ef47a5e4f1
"mac80211/minstrel_ht: fix cck rate sampling"
Cc: stable@vger.kernel.org # 3.10
Reported-by: Tom Gundersen <teg@jklm.no>
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
A lot of drivers check the frame protocol for ETH_P_PAE,
for various reasons (like making those more reliable).
Add a new flags bitmap to the TX control info and a new
flag indicating the control port protocol is in use to
let all drivers also apply such logic to other control
port protocols, should they be configured.
Also use the new flag in the iwlwifi drivers.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
according to IEEE 802.11-2012 section 18, various timings change
when using 5 MHz and 10 MHz. Reflect this by using a "shift" when
calculating durations.
Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
5 and 10 MHz support needs to know the current operating channel width,
add the chandef to the rate control API.
Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
The CCK group needs special treatment to set the right flags and rate
index. Add this missing check to prevent setting broken rates for tx
packets.
Cc: stable@vger.kernel.org # 3.10
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Pass the rate selection table to mac80211 from minstrel_ht_update_stats.
Only rates for sample attempts are set in info->control.rates.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Initialize {mp,mi}->{max_tp_rate,max_tp_rate2,max_prob_rate} in
minstrel_ht's rate_init and rate_update.
Signed-off-by: Karl Beldan <karl.beldan@rivierawaves.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
minstrel_ht initializes max_tp_rate max_tp_rate2 and max_prob_rate to
zero both for minstrel_ht_sta and minstrel_mcs_group_data.
This is wrong since there is no guarantee that the 1st rate of any
group is supported.
Signed-off-by: Karl Beldan <karl.beldan@rivierawaves.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
max_tp_rate2 and max_prob_rate tend to get used occasionally during
retransmission, which is more useful for the statistics than probing
with individual probe packets.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Slow rates that have >95% success probability do not need to be
monitored continuously. When the channel conditions change rapidly, the
slow sampling results are useless anyway. When conditions change slowly,
they will be monitored by gradual downgrading of the actively used
rates. This patch slightly improves throughput under good conditions.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Under load, otherwise stable rates can easily fluctuate because of
collisions. In my tests on a clean channel, the success probability of
the max throughput rate often stays somewhere between 90% and 100% under
load. This can cause some unnecessary switching to lower rates.
This patch improves stability by treating success probability values
between 90% and 100% the same.
In my tests on a 3x3 HT20 link with lots of TCP traffic, it improves the
average throughput by a few mbit/s.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
While minstrel bootstraps and fills the success probabilities of each
rate the lowest rate has typically a very high success probability
(often 100% in our tests).
Its statistics are never updated but considered to setup the mrr chain.
In our tests we see that especially the 3rd mrr stage (which is that
rate providing highest success probability) is filled with the lowest rate
because its initial high sucess probability is never updated. By design
the 4th mrr stage is filled with the lowest rate so often 3rd and 4th
mrr stage are equal.
This patch follows minstrels general approach of assuming as little
as possible about rate dependencies. Consequently we include the
lowest rate into the random sampling table to get balanced up-to-date
statistics of all rates and therefore balanced decisions.
Acked-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Both rate control algorithms (minstrel and minstrel_ht) calculate
averages based on EWMA. Shift function minstrel_ewma() into
rc80211_minstrel.h and make use of it in both minstrel version.
Also shift the default EWMA level (75%) definition to the header file
and clean up variable usage.
Acked-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
The last minstrel_ht changes increased the sampling frequency for
potentially useful rates to decrease the response time to rate
fluctuations. This caused an increase in sampling frequency that can
slightly reduce throughput, so this patch limits the sampling attempts
to one per rate instead of two.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
A sample attempt should only count in mi->sample_tries if the sample
attempt wasn't skipped based on slower rate criteria.
This patch increases the sampling frequency for potentially desirable
rates and thus enables faster recovery from interference or collisions.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
If a rate is below the max_tp_rate, sample it frequently if:
- it is above max_tp_rate2, or
- it is above max_prob_rate and is a candidate for max_prob_rate
(has fewer streams than max_tp_rate).
This helps the retry chain recover more quickly from bad statistics
caused by collisions or interference, and slightly reduces throughput
fluctuations with higher rates.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Try to sample all available rates, as sample attempts do not cost much
airtime and are appropriately spaced based on the average A-MPDU length.
This helps with faster recovery on rate fluctuations.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
max_prob_rate should be selected to be very reliable, however limiting
it to single-stream on 3-stream devices is a bit much.
Allow max_prob_rate to use one stream less than the max_tp_rate.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
At high data rates the average frame transmission durations are small
enough for rounding errors to matter, sometimes causing minstrel to use
slightly lower transmit rates than necessary.
To fix this, change the unit of the duration value to nanoseconds
instead of microseconds, and reorder the multiplications/divisions when
calculating the throughput metric so that they don't overflow or
truncate prematurely.
At 2-stream HT40 this makes TCP throughput a bit more stable.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Instead of modifying the HT SMPS capability field
for stations, track the SMPS mode explicitly in a
new field in the station struct and use it in the
drivers that care about it. This simplifies the
code using it.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
For VHT, many more bandwidth changes are possible. As a first
step, stop toggling the IEEE80211_HT_CAP_SUP_WIDTH_20_40 flag
in the HT capabilities and instead introduce a bandwidth field
indicating the currently usable bandwidth to transmit to the
station. Of course, make all drivers use it.
To achieve this, make ieee80211_ht_cap_ie_to_sta_ht_cap() get
the station as an argument, rather than the new capabilities,
so it can set up the new bandwidth field.
If the station is a VHT station and VHT bandwidth is in use,
also set the bandwidth accordingly.
Doing this allows us to get rid of the supports_40mhz flag as
the HT capabilities now reflect the true capability instead of
the current setting.
While at it, also fix ieee80211_ht_cap_ie_to_sta_ht_cap() to not
ignore HT cap overrides when MCS TX isn't supported (not that it
really happens...)
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
When MCS rates start to get bad in 2.4 GHz because of long range or
strong interference, CCK rates can be a lot more robust.
This patch adds a pseudo MCS group containing CCK rates (long preamble
in the lower 4 slots, short preamble in the upper slots).
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
[make minstrel_ht_get_stats static]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
It's more of an unnecessary micro-optimization and it prevents switching
from long-GI to short-GI in HT20/single-stream for the lowest rate
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
When sample_idx is set to a value other than -1 it activates
the IEEE80211_TX_CTL_RATE_CTRL_PROBE flag which disables
frame aggregation. To allow frame aggregation during fixed
rate it is necessary to set max_tp_rate, max_tp_rate2 and
max_prob_rate instead of sample_idx.
Signed-off-by: Sylvain Roger Rieunier <sylvain.roger.rieunier@gmail.com>
[reword commit message a bit]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
msp has type struct minstrel_ht_sta_priv not struct minstrel_ht_sta.
(This incorporates the fixup originally posted as "mac80211: fix kzalloc
memory corruption introduced in minstrel_ht". -- JWL)
Reported-by: Fengguang Wu <wfg@linux.intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Removes hw.conf.channel usage from the following functions:
* ieee80211_mandatory_rates
* ieee80211_sta_get_rates
* ieee80211_frame_duration
* ieee80211_rts_duration
* ieee80211_ctstoself_duration
This is in preparation for multi-channel operation.
Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The channel type argument to the rate_update()
callback isn't really the correct way to give
the rate control algorithm about the desired
RX bandwidth of the peer.
Remove this argument, and instead update the
STA capabilities with 20/40 appropriately. The
SMPS update done by this callback works in the
same way, so this makes the callback cleaner.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The current max throughput rate is known to be good as otherwise it
wouldn't be the max throughput rate. Since rate sampling can introduce
some overhead (by adding RTS for example or due to not aggregating the
frame) don't sample the max throughput rate.
Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Acked-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Disable multi stream rates (MCS > 7) when a STA is in static SMPS mode
since it has only one active rx chain. Hence, it doesn't even make
sense to sample multi stream rates.
Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Remove unused function parameters in the following functions:
minstrel_calc_rate_ewma()
minstrel_ht_calc_tp()
minstrel_aggr_check()
minstrel_ht_set_rate()
Signed-off-by: Patrick Kelle <patrick.kelle81@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Finding the group index for a specific rate is done by looping through
all groups and returning if the correct one is found. This code is
called for each tx'ed frame and thus it makes sense to reduce its
runtime.
Do this by calculating the group index by this formula based on the SGI
and HT40 flags as well as the stream number:
idx = (HT40 * 2 * MINSTREL_MAX_STREAMS) +
(SGI * MINSTREL_MAX_STREAMS) +
(streams - 1)
Hence, the groups are ordered by th HT40 flag first, then by the SGI
flag and afterwards by the number of used streams.
This should reduce the runtime of minstrel_ht_get_group_idx
considerable.
Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Acked-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
