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2021-01-22mac80211: remove legacy minstrel rate controlFelix Fietkau1-185/+0
Now that minstrel_ht supports legacy rates, it is no longer needed Signed-off-by: Felix Fietkau <nbd@nbd.name> Link: https://lore.kernel.org/r/20210115120242.89616-4-nbd@nbd.name Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2021-01-22mac80211: minstrel_ht: add support for OFDM rates on non-HT clientsFelix Fietkau1-0/+1
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>
2020-11-12mac80211: minstrel: remove deferred sampling codeFelix Fietkau1-1/+0
Deferring sampling attempts to the second stage has some bad interactions with drivers that process the rate table in hardware and use the probe flag to indicate probing packets (e.g. most mt76 drivers). On affected drivers it can lead to probing not working at all. If the link conditions turn worse, it might not be such a good idea to do a lot of sampling for lower rates in this case. Fix this by simply skipping the sample attempt instead of deferring it, but keep the checks that would allow it to be sampled if it was skipped too often, but only if it has less than 95% success probability. Also ensure that IEEE80211_TX_CTL_RATE_CTRL_PROBE is set for all probing packets. Cc: stable@vger.kernel.org Fixes: cccf129f820e ("mac80211: add the 'minstrel' rate control algorithm") Signed-off-by: Felix Fietkau <nbd@nbd.name> Link: https://lore.kernel.org/r/20201111183359.43528-2-nbd@nbd.name Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2019-10-11mac80211: minstrel_ht: rename prob_ewma to prob_avg, use it for the new averageFelix Fietkau1-14/+9
Reduces per-rate data structure size Signed-off-by: Felix Fietkau <nbd@nbd.name> Link: https://lore.kernel.org/r/20191008171139.96476-3-nbd@nbd.name Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2019-10-11mac80211: minstrel_ht: replace rate stats ewma with a better moving averageFelix Fietkau1-1/+55
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>
2019-08-21mac80211: minstrel_ht: improve rate probing for devices with static fallbackFelix Fietkau1-0/+1
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>
2019-06-19treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500Thomas Gleixner1-4/+1
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>
2018-10-11mac80211: rc80211_minstrel: remove variance / stddev calculationFelix Fietkau1-25/+1
When there are few packets (e.g. for sampling attempts), the exponentially weighted variance is usually vastly overestimated, making the resulting data essentially useless. As far as I know, there has not been any practical use for this, so let's not waste any cycles on it. Signed-off-by: Felix Fietkau <nbd@nbd.name> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2018-10-11mac80211: minstrel: merge with minstrel_ht, always enable VHT supportFelix Fietkau1-2/+0
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>
2018-10-11mac80211: minstrel: remove unnecessary debugfs cleanup codeFelix Fietkau1-7/+0
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>
2016-12-15mac80211: minstrel: make prob_ewma u16 instead of u32Felix Fietkau1-1/+1
Saves about 1.2 KiB memory per station Signed-off-by: Felix Fietkau <nbd@nbd.name> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2016-12-15mac80211: minstrel: store probability variance instead of standard deviationFelix Fietkau1-11/+14
This avoids the costly int_sqrt calls in the statistics update and moves it to the debugfs code instead. This also fixes an overflow in the previous standard deviation calculation. Signed-off-by: Thomas Huehn <thomas.huehn@evernet-eg.de> Signed-off-by: Felix Fietkau <nbd@nbd.name> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2016-12-15mac80211: minstrel: reduce MINSTREL_SCALEFelix Fietkau1-1/+1
The loss of a bit of extra precision does not hurt the calculation, 12 bits is still enough to calculate probabilities well. Reducing the scale makes it easier to avoid overflows Signed-off-by: Felix Fietkau <nbd@nbd.name> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2016-12-15mac80211: minstrel: remove cur_prob from debugfsFelix Fietkau1-2/+0
This field is redundant, because it is simply last success divided by last attempt count. Removing it from the rate stats struct saves about 1.2 KiB per HT station. Signed-off-by: Felix Fietkau <nbd@nbd.name> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2016-12-15mac80211: minstrel_ht: make att_hist and succ_hist u32 instead of u64Felix Fietkau1-1/+1
They are only used for debugging purposes and take a very long time to overflow. Visibly reduces the size of the per-sta rate control data. Signed-off-by: Felix Fietkau <nbd@nbd.name> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2015-04-01mac80211: add standard deviation to Minstrel statsThomas Huehn1-1/+21
This patch adds the statistical descriptor "standard deviation" to better describe the current properties of Minstrel and Minstrel-HTs success probability distribution. The standard deviation (SD) is calculated as exponential weighted moving standard deviation (EWMSD) and its current value is added as new column in all rc_stats (in debugfs). Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de> Acked-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2015-04-01mac80211: reduce calculation costs of EWMAThomas Huehn1-1/+6
This patch reduces the calculation costs of the EWMA macro from "2x multiplication and 1 addition" down to "1x multiplication and 2x additions". This slightly improves performance depending on the CPU architecture. Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de> Acked-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2015-04-01mac80211: add max lossless throughput per rateThomas Huehn1-1/+1
This patch adds the new statistic "maximum possible lossless throughput" to Minstrels and Minstrel-HTs rc_stats (in debugfs). This enables comprehensive comparison between current per-rate throughput and max. achievable per-rate throughput. Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de> Acked-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2015-04-01mac80211: restructure per-rate throughput calculation into functionThomas Huehn1-3/+1
This patch moves Minstrels and Minstrel-HTs per-rate throughput calculation (EWMA(thr)) into a dedicated function to be called. Therefore the variable "unsigned int cur_tp" within struct "minstrel_rate_stats" becomes obsolete. and is removed to free up its space. Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de> Acked-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2015-04-01mac80211: improve Minstrel variable & function namingThomas Huehn1-5/+8
This patch ensures a consistent usage of variable names for type "minstrel_rate_stats" to be used as "mrs" and from type minstrel_rate as "mr" across both Minstrel & Minstrel-HT. In addition some variable and function names got changed to more meaningful ones. Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de> Acked-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2015-04-01mac80211: unify Minstrel & Minstrel-HTs calculation of rate statisticsThomas Huehn1-0/+3
This patch unifies the calculation of Minstrels and Minstrel-HTs per-rate statistic. The new common function minstrel_calc_rate_stats() is called when a statistic update is performed. Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de> Acked-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2015-04-01mac80211: add new Minstrel statistic output via csvThomas Huehn1-3/+3
This patch adds a new debugfs file "rc_stats_csv" to output Minstrels statistics in a common csv format that is easy to parse. Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de> Signed-off-by: Stefan Venz <ikstream86@gmail.com> Acked-by: Felix Fietkau <nbd@openwrt.org> [remove printing current time of day] Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2014-12-19mac80211: minstrel: reduce size of struct minstrel_rate_statsFelix Fietkau1-7/+8
On minstrel_ht, the size of the per-sta struct is almost 18k, making it an order-3 allocation. A few fields inside the per-rate statistics are bigger than they need to be. This patch reduces the size enough to cut down the per-sta struct to about 13k (order-2 allocation). Signed-off-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2014-09-11mac80211: Unify rate statistic variables between Minstrel & Minstrel_HTThomas Huehn1-19/+24
Minstrel and Mintrel_HT used there own structs to keep track of rate statistics. Unify those variables in struct minstrel_rate_states and move it to rc80211_minstrel.h for common usage. This is a clean-up patch to prepare Minstrel and Minstrel_HT codebase for upcoming TPC. Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de> Acked-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2014-02-04mac80211: make rate control ops constJohannes Berg1-1/+1
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>
2013-04-22mac80211/minstrel: use the new rate control APIFelix Fietkau1-0/+2
Pass the rate selection table to mac80211 from minstrel_update_stats. Only rates for sample attempts are set in info->control.rates, with deferred sampling, only the second slot gets changed. Signed-off-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2013-04-17mac80211: optimize minstrel_ewmaKarl Beldan1-2/+3
Use powers of two in ewma of minstrel. This changes : - EWMA_DIV from 100 to 2^7 - EWMA_LEVEL from 75 (/EWMA_DIV=100) to 2^6 + 2^5 (/EWMA_DIV=128) Note that this changes EWMA_DIV - EWMA_LEVEL from 25 to 2^5 and keeps EWMA_LEVEL / EWMA_DIV == 0.75. 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>
2013-03-06mac80211: improve minstrels rate sorting by means of throughput & probabilityThomas Huehn1-3/+5
This patch improves the way minstrel sorts rates according to throughput and success probability. 3 FOR-loops across the entire rate set in function minstrel_update_stats() which where used to determine the fastest, second fastest and most robust rate are reduced to 1 FOR-loop. The sorted list of rates according throughput is extended to the best four rates as we need them in upcoming joint rate and power control. The sorting is done via the new function minstrel_sort_best_tp_rates(). The most robust rate selection is aligned with minstrel_ht's approach. Once any success probability is above 95% the one with the highest throughput is chosen as most robust rate. If success probabilities of all rates are below 95%, the rate with the highest succ. prob. is elected as most robust one 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>
2013-03-06mac80211: add lowest rate into minstrel's random rate sampling tableThomas Huehn1-1/+3
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>
2013-03-06mac80211: extend minstrel's rate sampling to avoid unsampled ratesThomas Huehn1-0/+1
Minstrel's decision which rate should be directly sampled within the 1st mrr stage is limited to such rates faster than the current max throughput rate. All rates below the current max. throughput rate are indirectly sampled via the 2nd mrr stage. This approach leads to deprecated per rate statistics and therfore a deprecated mrr chain setup. This patch uses the sampling approach from minstrel_ht. A counter is added to sum all indirect sample attempts per rate. After 20 indirect sampling attempts the rate is directly sampled within the 1st mrr stage. Therefore more up-to-date statistics for all rates are maintained and used to setup the mrr chain. 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>
2013-03-06mac80211: add documentation and verbose variable names inThomas Huehn1-1/+1
Add documentation and more verbose variable names to minstrel's multi-rate-retry setup within function minstrel_get_rate() to increase the readability of the algorithm. 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>
2013-03-06mac80211: merge value scaling macros of minstrel_ht and minstrelThomas Huehn1-0/+5
Both minstrel versions use individual ways to scale up integer values to perform calculations. Merge minstrel_ht's scaling macros into minstrels header file and use them in both minstrel versions. 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>
2013-03-06mac80211: merge EWMA calculation of minstrel_ht and minstrelThomas Huehn1-1/+12
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>
2013-02-13mac80211/minstrel_ht: add support for using CCK ratesFelix Fietkau1-0/+2
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>
2011-06-01minstrel_ht: fixed rate mode through debugfsZefir Kurtisi1-0/+12
Found several threads about fixed rate mode in minstrel_ht for test environments, but no patches for it. This patch provides such a mode through debugfs. Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-03-10minstrel: make the rate control ops reusable from another rc implementationFelix Fietkau1-0/+6
This patch makes it possible to reuse the minstrel rate control ops from another rate control module. This is useful in preparing for the new 802.11n implementation of minstrel, which will reuse the old code for legacy stations. Signed-off-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-03-10minstrel: simplify and fix debugfs codeFelix Fietkau1-0/+5
This patch cleans up the debugfs read function for the statistics by using simple_read_from_buffer instead of its own semi-broken hack. Also removes a useless member of the minstrel debugfs info struct. Signed-off-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-08-28mac80211: Remove unnused throughput field from minstrel_rate.Arnd Hannemann1-1/+0
I noticed that the throughput field of the minstrel_rate struct is never used, so remove it. Signed-off-by: Arnd Hannemann <hannemann@nets.rwth-aachen.de> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2008-10-31minstrel: improve performance for non-MRR driversFelix Fietkau1-0/+2
This patch enhances minstrel's performance for non-MRR setups, by preventing it from sampling slower rates with >95% success probability and by putting at least 1 non-sample frame between several sample frames. Signed-off-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2008-10-06mac80211: add the 'minstrel' rate control algorithmFelix Fietkau1-0/+85
Signed-off-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: John W. Linville <linville@tuxdriver.com>
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