Commit Graph

160 Commits

Author SHA1 Message Date
Jonas Jelonek 569cf386ec mac80211: minstrel_ht: support ieee80211_rate_status
This patch adds support for the new struct ieee80211_rate_status and its
annotation in struct ieee80211_tx_status in minstrel_ht.

In minstrel_ht_tx_status, a check for the presence of instances of the
new struct in ieee80211_tx_status is added. Based on this, minstrel_ht
then gets and updates internal rate stats with either struct
ieee80211_rate_status or ieee80211_tx_info->status.rates.
Adjusted variants of minstrel_ht_txstat_valid, minstrel_ht_get_stats,
minstrel_{ht/vht}_get_group_idx are added which use struct
ieee80211_rate_status and struct rate_info instead of the legacy structs.

struct rate_info from cfg80211.h does not provide whether short preamble
was used for the transmission. So we retrieve this information from VIF
and STA configuration and cache it in a new flag in struct minstrel_ht_sta
per rate control instance.

Compile-Tested: current wireless-next tree with all flags on
Tested-on: Xiaomi 4A Gigabit (MediaTek MT7603E, MT7612E) with OpenWrt
                Linux 5.10.113

Signed-off-by: Jonas Jelonek <jelonek.jonas@gmail.com>
Link: https://lore.kernel.org/r/20220509173958.1398201-3-jelonek.jonas@gmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2022-05-16 10:07:58 +02:00
Peter Seiderer ee0e16ab75 mac80211: minstrel_ht: fill all requested rates
Fill all requested rates (in case of ath9k 4 rate slots are
available, so fill all 4 instead of only 3), improves throughput in
noisy environment.

Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Link: https://lore.kernel.org/r/20220402153014.31332-2-ps.report@gmx.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2022-05-16 10:03:39 +02:00
Sriram R 046d2e7c50 mac80211: prepare sta handling for MLO support
Currently in mac80211 each STA object is represented
using sta_info datastructure with the associated
STA specific information and drivers access ieee80211_sta
part of it.

With MLO (Multi Link Operation) support being added
in 802.11be standard, though the association is logically
with a single Multi Link capable STA, at the physical level
communication can happen via different advertised
links (uniquely identified by Channel, operating class,
BSSID) and hence the need to handle multiple link
STA parameters within a composite sta_info object
called the MLD STA. The different link STA part of
MLD STA are identified using the link address which can
be same or different as the MLD STA address and unique
link id based on the link vif.

To support extension of such a model, the sta_info
datastructure is modified to hold multiple link STA
objects with link specific params currently within
sta_info moved to this new structure. Similarly this is
done for ieee80211_sta as well which will be accessed
within mac80211 as well as by drivers, hence trivial
driver changes are expected to support this.

For current non MLO supported drivers, only one link STA
is present and link information is accessed via 'deflink'
member.

For MLO drivers, we still need to define the APIs etc. to
get the correct link ID and access the correct part of
the station info.

Currently in mac80211, all link STA info are accessed directly
via deflink. These will be updated to access via link pointers
indexed by link id with MLO support patches, with link id
being 0 for non MLO supported cases.

Except for couple of macro related changes, below spatch takes
care of updating mac80211 and driver code to access to the
link STA info via deflink.

  @ieee80211_sta@
  struct ieee80211_sta *s;
  struct sta_info *si;
  identifier var = {supp_rates, ht_cap, vht_cap, he_cap, he_6ghz_capa, eht_cap, rx_nss, bandwidth, txpwr};
  @@

  (
    s->
  -    var
  +    deflink.var
  |
   si->sta.
  -    var
  +    deflink.var
  )

  @sta_info@
  struct sta_info *si;
  identifier var = {gtk, pcpu_rx_stats, rx_stats, rx_stats_avg, status_stats, tx_stats, cur_max_bandwidth};
  @@

  (
    si->
  -    var
  +    deflink.var
  )

Signed-off-by: Sriram R <quic_srirrama@quicinc.com>
Link: https://lore.kernel.org/r/1649086883-13246-1-git-send-email-quic_srirrama@quicinc.com
[remove MLO-drivers notes from commit message, not clear yet; run spatch]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2022-04-11 16:42:03 +02:00
Peter Seiderer 5c6dd7bd56 mac80211: minstrel_ht: fix where rate stats are stored (fixes debugfs output)
Using an ath9k card the debugfs output of minstrel_ht looks like the following
(note the zero values for the first four rates sum-of success/attempts):

             best    ____________rate__________    ____statistics___    _____last____    ______sum-of________
mode guard #  rate   [name   idx airtime  max_tp]  [avg(tp) avg(prob)]  [retry|suc|att]  [#success | #attempts]
OFDM       1    DP     6.0M  272    1640     5.2       3.1      53.8       3     0 0             0   0
OFDM       1   C       9.0M  273    1104     7.7       4.6      53.8       4     0 0             0   0
OFDM       1  B       12.0M  274     836    10.0       6.0      53.8       4     0 0             0   0
OFDM       1 A    S   18.0M  275     568    14.3       8.5      53.8       5     0 0             0   0
OFDM       1      S   24.0M  276     436    18.1       0.0       0.0       5     0 1            80   1778
OFDM       1          36.0M  277     300    24.9       0.0       0.0       0     0 1             0   107
OFDM       1      S   48.0M  278     236    30.4       0.0       0.0       0     0 0             0   75
OFDM       1          54.0M  279     212    33.0       0.0       0.0       0     0 0             0   72

Total packet count::    ideal 16582      lookaround 885
Average # of aggregated frames per A-MPDU: 1.0

Debugging showed that the rate statistics for the first four rates where
stored in the MINSTREL_CCK_GROUP instead of the MINSTREL_OFDM_GROUP because
in minstrel_ht_get_stats() the supported check was not honoured as done in
various other places, e.g net/mac80211/rc80211_minstrel_ht_debugfs.c:

 74                 if (!(mi->supported[i] & BIT(j)))
 75                         continue;

With the patch applied the output looks good:

              best    ____________rate__________    ____statistics___    _____last____    ______sum-of________
mode guard #  rate   [name   idx airtime  max_tp]  [avg(tp) avg(prob)]  [retry|suc|att]  [#success | #attempts]
OFDM       1    D      6.0M  272    1640     5.2       5.2     100.0       3     0 0             1   1
OFDM       1   C       9.0M  273    1104     7.7       7.7     100.0       4     0 0            38   38
OFDM       1  B       12.0M  274     836    10.0       9.9      89.5       4     2 2           372   395
OFDM       1 A   P    18.0M  275     568    14.3      14.3      97.2       5    52 53         6956   7181
OFDM       1      S   24.0M  276     436    18.1       0.0       0.0       0     0 1             6   163
OFDM       1          36.0M  277     300    24.9       0.0       0.0       0     0 1             0   35
OFDM       1      S   48.0M  278     236    30.4       0.0       0.0       0     0 0             0   38
OFDM       1      S   54.0M  279     212    33.0       0.0       0.0       0     0 0             0   38

Total packet count::    ideal 7097      lookaround 287
Average # of aggregated frames per A-MPDU: 1.0

Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Link: https://lore.kernel.org/r/20220404165414.1036-1-ps.report@gmx.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2022-04-11 15:50:36 +02:00
Johannes Berg 453a2a8205 mac80211: remove unused macros
Various macros in mac80211 aren't used, remove them. In one
case it's used under ifdef, so ifdef it for the W=2 warning.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20220202104617.5172d7fd878e.I2f1fce686a2b71003f083b2566fb09cf16b8165a@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2022-02-04 16:26:27 +01:00
Peter Seiderer dc53078320 mac80211: minstrel_ht: remove unused SAMPLE_SWITCH_THR define
Remove unused SAMPLE_SWITCH_THR define.

Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Link: https://lore.kernel.org/r/20211116221244.30844-1-ps.report@gmx.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2021-11-26 11:51:07 +01:00
Zheng Yongjun ab4040df6e mac80211: fix some spelling mistakes
Fix some spelling mistakes in comments:
freeed  ==> freed
addreses  ==> addresses
containging  ==> containing
capablity  ==> capability
sucess  ==> success
atleast  ==> at least

Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>
Link: https://lore.kernel.org/r/20210607150047.2855962-1-zhengyongjun3@huawei.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2021-06-23 12:36:32 +02:00
Felix Fietkau 08a46c6420 mac80211: move A-MPDU session check from minstrel_ht to mac80211
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>
2021-06-23 11:29:13 +02:00
Philipp Borgers 0edab4ff84 mac80211: minstrel_ht: ignore frame that was sent with noAck flag
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>
2021-06-23 10:59:44 +02:00
Felix Fietkau 1236af327a mac80211: minstrel_ht: fix sample time check
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>
2021-06-18 11:35:29 +02:00
Colin Ian King bab7f5ca81 mac80211: minstrel_ht: remove extraneous indentation on if statement
The increment of idx is indented one level too deeply, clean up the
code by removing the extraneous tab.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210416095137.2033469-1-colin.king@canonical.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2021-04-19 12:00:48 +02:00
Wei Yongjun 026dfac85f mac80211: minstrel_ht: remove unused variable 'mg' in minstrel_ht_next_jump_rate()
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>
2021-04-08 11:20:45 +02:00
Johannes Berg 29175be06d mac80211: minstrel_ht: remove unused variable 'mg'
This probably came in through some refactoring and what is
now a call to minstrel_ht_group_min_rate_offset(), remove
the unused variable.

Reported-by: kernel test robot <lkp@intel.com>
Acked-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20210219105744.f2538a80f6cf.I3d53554c158d5b896ac07ea546bceac67372ec28@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2021-03-16 21:13:13 +01:00
Felix Fietkau c0eb09aa7e mac80211: minstrel_ht: remove sample rate switching code for constrained devices
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>
2021-02-12 08:58:22 +01:00
Felix Fietkau 80d55154b2 mac80211: minstrel_ht: significantly redesign the rate probing strategy
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>
2021-02-12 08:57:45 +01:00
Felix Fietkau 7aece471a0 mac80211: minstrel_ht: reduce the need to sample slower rates
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>
2021-02-12 08:57:24 +01:00
Felix Fietkau 2012a2f7bc mac80211: minstrel_ht: update total packets counter in tx status path
Keep the update in one place and prepare for further rework

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20210127055735.78599-2-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2021-02-12 08:56:43 +01:00
Felix Fietkau a42fa256f6 mac80211: minstrel_ht: use bitfields to encode rate indexes
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>
2021-02-12 08:56:28 +01:00
Felix Fietkau d3b9b45f7e mac80211: minstrel_ht: fix regression in the max_prob_rate fix
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>
2021-01-27 22:06:38 +01:00
Felix Fietkau 347c2989a8 mac80211: minstrel_ht: fix rounding error in throughput calculation
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>
2021-01-22 09:11:37 +01:00
Felix Fietkau 7e2123abc5 mac80211: minstrel_ht: increase stats update interval
The shorter interval was leading to too many frames being used for probing

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20210115120242.89616-9-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2021-01-22 09:11:37 +01:00
Felix Fietkau a7fca4e403 mac80211: minstrel_ht: fix max probability rate selection
- 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>
2021-01-22 09:11:37 +01:00
Felix Fietkau 019c6fc278 mac80211: minstrel_ht: improve sample rate selection
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>
2021-01-22 09:11:37 +01:00
Felix Fietkau 1ae8bba9a2 mac80211: minstrel_ht: improve ampdu length estimation
If the driver does not report A-MPDU length, estimate it based on the rate.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20210115120242.89616-6-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2021-01-22 09:11:37 +01:00
Felix Fietkau eeafcb0c80 mac80211: minstrel_ht: remove old ewma based rate average code
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>
2021-01-22 09:11:37 +01:00
Felix Fietkau cbda98c710 mac80211: remove legacy minstrel rate control
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>
2021-01-22 09:11:37 +01:00
Felix Fietkau a7844a5384 mac80211: minstrel_ht: add support for OFDM rates on non-HT clients
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>
2021-01-22 09:11:37 +01:00
Felix Fietkau f84de06398 mac80211: minstrel_ht: clean up CCK code
- 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>
2021-01-22 09:11:37 +01:00
David S. Miller 745bd6f44c 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
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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>
2020-05-26 20:17:35 -07:00
Johannes Berg dba25b04c6 mac80211: minstrel_ht_assign_best_tp_rates: remove redundant test
We know this pointer isn't NULL and in fact dereferenced it before,
remove the redundant test.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20200326150855.adf551928846.Iae9015573d6c350cc1b12a311d6d13d086beec6c@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2020-04-24 12:33:43 +02:00
Johannes Berg 6cb5f3ea46 mac80211: populate debugfs only after cfg80211 init
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>
2020-04-24 11:30:13 +02:00
Felix Fietkau 5f63afe028 mac80211: minstrel_ht: rename prob_ewma to prob_avg, use it for the new average
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>
2019-10-11 10:31:45 +02:00
Felix Fietkau b1103d2567 mac80211: minstrel_ht: replace rate stats ewma with a better moving average
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>
2019-10-11 10:31:32 +02:00
Felix Fietkau 8f2f495ca9 mac80211: minstrel: remove divisions in tx status path
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>
2019-10-11 10:31:15 +02:00
Colin Ian King b26af93044 mac80211: minstrel_ht: fix infinite loop because supported is not being shifted
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>
2019-08-22 21:58:18 +02:00
Felix Fietkau 48cb39522a mac80211: minstrel_ht: improve rate probing for devices with static fallback
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>
2019-08-21 11:10:13 +02:00
Felix Fietkau 21f7981b4b mac80211: minstrel_ht: fix default max throughput rate indexes
Use the first supported rate instead of 0 (which can be invalid)

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20190820095449.45255-3-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2019-08-21 11:09:37 +02:00
Felix Fietkau f793c7eedd mac80211: minstrel_ht: reduce unnecessary rate probing attempts
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>
2019-08-21 11:09:20 +02:00
Felix Fietkau 56dd918ff0 mac80211: minstrel_ht: fix per-group max throughput rate initialization
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>
2019-08-21 11:08:21 +02:00
David S. Miller 92ad6325cb Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Minor SPDX change conflict.

Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-22 08:59:24 -04:00
Thomas Gleixner d2912cb15b treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500
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>
2019-06-19 17:09:55 +02:00
Johannes Berg 1e87fec9fa mac80211: call rate_control_send_low() internally
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>
2019-06-14 14:17:37 +02:00
Felix Fietkau c2b17948fc mac80211: minstrel_ht: automatically calculate rate duration shift
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>
2019-04-26 13:02:11 +02:00
Felix Fietkau 7f2e12e1bf mac80211: minstrel_ht: add support for rates with 4 spatial streams
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>
2019-04-26 13:02:11 +02:00
Felix Fietkau 77f7ffdc33 mac80211: minstrel_ht: add flag to indicate missing/inaccurate tx A-MPDU length
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>
2019-01-19 09:56:56 +01:00
Felix Fietkau f4ec7cb0f9 mac80211: minstrel: do not sample rates 3 times slower than max_prob_rate
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>
2018-10-11 16:01:04 +02:00
Felix Fietkau 972b66b86f mac80211: minstrel: fix sampling/reporting of CCK rates in HT mode
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>
2018-10-11 16:01:03 +02:00
Felix Fietkau 80df9be67c mac80211: minstrel: fix CCK rate group streams value
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>
2018-10-11 16:01:03 +02:00
Felix Fietkau 37439f2d6e mac80211: minstrel: fix using short preamble CCK rates on HT clients
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>
2018-10-11 16:01:02 +02:00
Felix Fietkau 202df504d7 mac80211: minstrel: reduce minstrel_mcs_groups size
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>
2018-10-11 16:01:02 +02:00