This avoids calling back into tx handlers from within the rate control module.
Preparation for deferring rate control until tx dequeue
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20210617163113.75815-1-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
QoS Data Frames that were sent with a No Ack policy should be ignored by
the minstrel statistics. There will never be an Ack for these frames so
there is no way to draw conclusions about the success of the transmission.
Signed-off-by: Philipp Borgers <borgers@mi.fu-berlin.de>
Link: https://lore.kernel.org/r/20210517120145.132814-1-borgers@mi.fu-berlin.de
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
We need to skip sampling if the next sample time is after jiffies, not before.
This patch fixes an issue where in some cases only very little sampling (or none
at all) is performed, leading to really bad data rates
Fixes: 80d55154b2 ("mac80211: minstrel_ht: significantly redesign the rate probing strategy")
Cc: stable@vger.kernel.org
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20210617103854.61875-1-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
GCC reports the following warning with W=1:
net/mac80211/rc80211_minstrel_ht.c:871:34: warning:
variable 'mg' set but not used [-Wunused-but-set-variable]
871 | struct minstrel_mcs_group_data *mg;
| ^~
This variable is not used in function , this commit
remove it to fix the warning.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Link: https://lore.kernel.org/r/20210326024843.987941-1-weiyongjun1@huawei.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This was added to mitigate the effects of too much sampling on devices that
use a static global fallback table instead of configurable multi-rate retry.
Now that the sampling algorithm is improved, this code path no longer performs
any better than the standard probing on affected devices.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20210127055735.78599-6-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
The biggest flaw in current minstrel_ht is the fact that it needs way too
many probing packets to be able to quickly find the best rate.
Depending on the wifi hardware and operating mode, this can significantly
reduce throughput when not operating at the highest available data rate.
In order to be able to significantly reduce the amount of rate sampling,
we need a much smarter selection of probing rates.
The new approach introduced by this patch maintains a limited set of
available rates to be tested during a statistics window.
They are split into distinct categories:
- MINSTREL_SAMPLE_TYPE_INC - incremental rate upgrade:
Pick the next rate group and find the first rate that is faster than
the current max. throughput rate
- MINSTREL_SAMPLE_TYPE_JUMP - random testing of higher rates:
Pick a random rate from the next group that is faster than the current
max throughput rate. This allows faster adaptation when the link changes
significantly
- MINSTREL_SAMPLE_TYPE_SLOW - test a rate between max_prob, max_tp2 and
max_tp in order to reduce the gap between them
In order to prioritize sampling, every 6 attempts are split into 3x INC,
2x JUMP, 1x SLOW.
Available rates are checked and refilled on every stats window update.
With this approach, we finally get a very small delta in throughput when
comparing setting the optimal data rate as a fixed rate vs normal rate
control operation.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20210127055735.78599-4-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
In order to more gracefully be able to fall back to lower rates without too
much throughput fluctuations, initialize all untested rates below tested ones
to the maximum probabilty of higher rates.
Usually this leads to untested lower rates getting initialized with a
probability value of 100%, making them better candidates for fallback without
having to rely on random probing
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20210127055735.78599-3-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Get rid of a lot of divisions and modulo operations
Reduces code size and improves performance
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20210127055735.78599-1-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Since mi->max_prob_rate is overwritten after the loop that calls
minstrel_ht_set_best_prob_rate, the new best rate needs to be written to *dest
Fixes: a7fca4e403 ("mac80211: minstrel_ht: fix max probability rate selection")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20210126154409.6755-1-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
On lower data rates, the throughput calculation has a significant rounding
error, causing rates like 48M and 54M OFDM to share the same throughput
value with >= 90% success probablity.
This is because the result of the division (prob_avg * 1000) / nsecs
is really small (8 in this example).
Improve accuracy by moving over some zeroes, making better use of the full
range of u32 before the division.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20210115120242.89616-10-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
- do not select rates faster than the max throughput rate if probability is lower
- reset previous rate before sorting again
This ensures that the max prob rate gets set to a more reliable rate
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20210115120242.89616-8-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Always allow sampling of rates faster than the primary max throughput rate.
When the second max_tp_rate is higher than the first one, sample attempts were
previously skipped, potentially causing rate control to get stuck at a slightly
lower rate
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20210115120242.89616-7-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
The new noise filter has been the default for a while now with no reported
downside and significant improvement compared to the old code.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20210115120242.89616-5-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
The legacy minstrel code is essentially unmaintained and receives only very
little testing. In order to bring the significant algorithm improvements from
minstrel_ht to legacy clients, this patch adds support for OFDM rates to
minstrel_ht and removes the fallback to the legacy codepath.
This also makes it work much better on hardware with rate selection constraints,
e.g. mt76.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20210115120242.89616-3-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
- move ack overhead out of rate duration table
- remove cck_supported, cck_supported_short
Preparation for adding OFDM legacy rates support
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20210115120242.89616-2-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
* hwsim improvements from Jouni and myself, to be able to
test more scenarios easily
* some more HE (802.11ax) support
* some initial S1G (sub 1 GHz) work for fractional MHz channels
* some (action) frame registration updates to help DPP support
* along with other various improvements/fixes
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Merge tag 'mac80211-next-for-net-next-2020-04-25' of git://git.kernel.org/pub/scm/linux/kernel/git/jberg/mac80211-next
Johannes Berg says:
====================
One batch of changes, containing:
* hwsim improvements from Jouni and myself, to be able to
test more scenarios easily
* some more HE (802.11ax) support
* some initial S1G (sub 1 GHz) work for fractional MHz channels
* some (action) frame registration updates to help DPP support
* along with other various improvements/fixes
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
When fixing the initialization race, we neglected to account for
the fact that debugfs is initialized in wiphy_register(), and
some debugfs things went missing (or rather were rerooted to the
global debugfs root).
Fix this by adding debugfs entries only after wiphy_register().
This requires some changes in the rate control code since it
currently adds debugfs at alloc time, which can no longer be
done after the reordering.
Reported-by: Jouni Malinen <j@w1.fi>
Reported-by: kernel test robot <rong.a.chen@intel.com>
Reported-by: Hauke Mehrtens <hauke@hauke-m.de>
Reported-by: Felix Fietkau <nbd@nbd.name>
Cc: stable@vger.kernel.org
Fixes: 52e04b4ce5 ("mac80211: fix race in ieee80211_register_hw()")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Sumit Garg <sumit.garg@linaro.org>
Link: https://lore.kernel.org/r/20200423111344.0e00d3346f12.Iadc76a03a55093d94391fc672e996a458702875d@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Rate success probability usually fluctuates a lot under normal conditions.
With a simple EWMA, noise and fluctuation can be reduced by increasing the
window length, but that comes at the cost of introducing lag on sudden
changes.
This change replaces the EWMA implementation with a moving average that's
designed to significantly reduce lag while keeping a bigger window size
by being better at filtering out noise.
It is only slightly more expensive than the simple EWMA and still avoids
divisions in its calculation.
The algorithm is adapted from an implementation intended for a completely
different field (stock market trading), where the tradeoff of lag vs
noise filtering is equally important. It is based on the "smoothing filter"
from http://www.stockspotter.com/files/PredictiveIndicators.pdf.
I have adapted it to fixed-point math with some constants so that it uses
only addition, bit shifts and multiplication
To better make use of the filtering and bigger window size, the update
interval time is cut in half.
For testing, the algorithm can be reverted to the older one via debugfs
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20191008171139.96476-2-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Use a slightly different threshold for downgrading spatial streams to
make it easier to calculate without divisions.
Slightly reduces CPU overhead.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20191008171139.96476-1-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Currently the for-loop will spin forever if variable supported is
non-zero because supported is never changed. Fix this by adding in
the missing right shift of supported.
Addresses-Coverity: ("Infinite loop")
Fixes: 48cb39522a ("mac80211: minstrel_ht: improve rate probing for devices with static fallback")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20190822122034.28664-1-colin.king@canonical.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
On some devices that only support static rate fallback tables sending rate
control probing packets can be really expensive.
Probing lower rates can already hurt throughput quite a bit. What hurts even
more is the fact that on mt76x0/mt76x2, single probing packets can only be
forced by directing packets at a different internal hardware queue, which
causes some heavy reordering and extra latency.
The reordering issue is mainly problematic while pushing lots of packets to
a particular station. If there is little activity, the overhead of probing is
neglegible.
The static fallback behavior is designed to pretty much only handle rate
control algorithms that use only a very limited set of rates on which the
algorithm switches up/down based on packet error rate.
In order to better support that kind of hardware, this patch implements a
different approach to rate probing where it switches to a slightly higher rate,
waits for tx status feedback, then updates the stats and switches back to
the new max throughput rate. This only triggers above a packet rate of 100
per stats interval (~50ms).
For that kind of probing, the code has to reduce the set of probing rates
a lot more compared to single packet probing, so it uses only one packet
per MCS group which is either slightly faster, or as close as possible to
the max throughput rate.
This allows switching between similar rates with different numbers of
streams. The algorithm assumes that the hardware will work its way lower
within an MCS group in case of retransmissions, so that lower rates don't
have to be probed by the high packets per second rate probing code.
To further reduce the search space, it also does not probe rates with lower
channel bandwidth than the max throughput rate.
At the moment, these changes will only affect mt76x0/mt76x2.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20190820095449.45255-4-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
On hardware with static fallback tables (e.g. mt76x2), rate probing attempts
can be very expensive.
On such devices, avoid sampling rates slower than the per-group max throughput
rate, based on the assumption that the fallback table will take care of probing
lower rates within that group if the higher rates fail.
To further reduce unnecessary probing attempts, skip duplicate attempts on
rates slower than the max throughput rate.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20190820095449.45255-2-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
The group number needs to be multiplied by the number of rates per group
to get the full rate index
Fixes: 5935839ad7 ("mac80211: improve minstrel_ht rate sorting by throughput & probability")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20190820095449.45255-1-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Based on 2 normalized pattern(s):
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
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 #
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 4122 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There's no rate control algorithm that *doesn't* want to call
it internally, and calling it internally will let us modify
its behaviour in the future.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
A per-group shift was added to reduce the size of the per-rate transmit
duration field to u16 without sacrificing a lot of precision
This patch changes the macros to automatically calculate the best value for
this shift based on the lowest rate within the group.
This simplifies adding more groups and slightly improves accuracy for some of
the existing groups.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This is needed for the upcoming driver for MT7615 4x4 802.11ac chipsets
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Some hardware (e.g. MediaTek MT7603) cannot report A-MPDU length in tx status
information. Add support for a flag to indicate that, to allow minstrel_ht
to use a fixed value in its internal calculation (which gives better results
than just defaulting to 1).
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
These rates are highly unlikely to be used quickly, even if the link
deteriorates rapidly. This improves throughput in cases where CCK rates
are not reliable enough to be skipped entirely during sampling.
Sampling these rates regularly can cost a lot of airtime.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Long/short preamble selection cannot be sampled separately, since it
depends on the BSS state. Because of that, sampling attempts to
currently not used preamble modes are not counted in the statistics,
which leads to CCK rates being sampled too often.
Fix statistics accounting for long/short preamble by increasing the
index where necessary.
Fix excessive CCK rate sampling by dropping unsupported sample attempts.
This improves throughput on 2.4 GHz channels
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Fixes a harmless underflow issue when CCK rates are actively being used
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
mi->supported[MINSTREL_CCK_GROUP] needs to be updated
short preamble rates need to be marked as supported regardless of
whether it's currently enabled. Its state can change at any time without
a rate_update call.
Fixes: 782dda00ab ("mac80211: minstrel_ht: move short preamble check out of get_rate")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
By storing a shift value for all duration values of a group, we can
reduce precision by a neglegible amount to make it fit into a u16 value.
This improves cache footprint and reduces size:
Before:
text data bss dec hex filename
10024 116 0 10140 279c rc80211_minstrel_ht.o
After:
text data bss dec hex filename
9368 116 0 9484 250c rc80211_minstrel_ht.o
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Legacy-only devices are not very common and the overhead of the extra
code for HT and VHT rates is not big enough to justify all those extra
lines of code to make it optional.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
debugfs entries are cleaned up by debugfs_remove_recursive already.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
If peer support reception of STBC and LDPC, enable them for better
performance.
Signed-off-by: Chaitanya TK <chaitanya.mgit@gmail.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
