linux/net/mac80211
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
..
aead_api.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
aead_api.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
aes_ccm.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
aes_cmac.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
aes_cmac.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
aes_gcm.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
aes_gmac.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
aes_gmac.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
agg-rx.c mac80211: add missing null return check from call to ieee80211_get_sband 2019-07-31 10:51:17 +02:00
agg-tx.c mac80211: simplify TX aggregation start 2019-10-04 13:58:13 +02:00
cfg.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-09-15 14:17:27 +02:00
chan.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
debug.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
debugfs_key.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-06-22 08:59:24 -04:00
debugfs_key.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
debugfs_netdev.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-06-22 08:59:24 -04:00
debugfs_netdev.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
debugfs_sta.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-06-22 08:59:24 -04:00
debugfs_sta.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
debugfs.c mac80211: AMPDU handling for rekeys with Extended Key ID 2019-07-26 13:29:10 +02:00
debugfs.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
driver-ops.c mac80211: don't warn about CW params when not using them 2019-07-20 21:40:32 +02:00
driver-ops.h mac80211: pass the vif to cancel_remain_on_channel 2019-07-26 13:08:28 +02:00
ethtool.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 432 2019-06-05 17:37:16 +02:00
fils_aead.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
fils_aead.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
he.c mac80211: fix possible NULL pointerderef in obss pd code 2019-08-21 10:58:32 +02:00
ht.c mac80211: add support for the ADDBA extension element 2019-07-29 16:40:22 +02:00
ibss.c mac80211: IBSS: avoid unneeded return value processing 2019-10-04 13:47:12 +02:00
ieee80211_i.h mac80211: IBSS: send deauth when expiring inactive STAs 2019-09-11 09:33:29 +02:00
iface.c mac80211: allow drivers to set max MTU 2019-09-11 09:33:29 +02:00
Kconfig Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2019-07-08 20:57:08 -07:00
key.c mac80211: don't check if key is NULL in ieee80211_key_link() 2019-09-11 09:33:28 +02:00
key.h mac80211: clear crypto tx tailroom counter upon keys enable 2019-09-11 09:33:28 +02:00
led.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
led.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
main.c mac80211: allow drivers to set max MTU 2019-09-11 09:33:29 +02:00
Makefile mac80211: minstrel: merge with minstrel_ht, always enable VHT support 2018-10-11 16:01:01 +02:00
mesh_hwmp.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
mesh_pathtbl.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
mesh_plink.c mac80211: implement HE support for mesh 2019-07-26 16:14:12 +02:00
mesh_ps.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
mesh_sync.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
mesh.c mac80211: implement HE support for mesh 2019-07-26 16:14:12 +02:00
mesh.h mac80211: implement HE support for mesh 2019-07-26 16:14:12 +02:00
michael.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
michael.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
mlme.c mac80211: IBSS: send deauth when expiring inactive STAs 2019-09-11 09:33:29 +02:00
ocb.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
offchannel.c mac80211: pass the vif to cancel_remain_on_channel 2019-07-26 13:08:28 +02:00
pm.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
rate.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-06-22 08:59:24 -04:00
rate.h mac80211: remove unused and unneeded remove_sta_debugfs callback 2019-07-26 13:21:12 +02:00
rc80211_minstrel_debugfs.c mac80211: rc80211_minstrel: remove variance / stddev calculation 2018-10-11 16:01:05 +02:00
rc80211_minstrel_ht_debugfs.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
rc80211_minstrel_ht.c mac80211: minstrel_ht: replace rate stats ewma with a better moving average 2019-10-11 10:31:32 +02:00
rc80211_minstrel_ht.h mac80211: minstrel_ht: improve rate probing for devices with static fallback 2019-08-21 11:10:13 +02:00
rc80211_minstrel.c mac80211: minstrel_ht: replace rate stats ewma with a better moving average 2019-10-11 10:31:32 +02:00
rc80211_minstrel.h mac80211: minstrel_ht: replace rate stats ewma with a better moving average 2019-10-11 10:31:32 +02:00
rx.c mac80211: Correctly set noencrypt for PAE frames 2019-08-29 16:40:00 +02:00
scan.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
spectmgmt.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
sta_info.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-09-15 14:17:27 +02:00
sta_info.h mac80211: add assoc-at support 2019-08-21 10:58:10 +02:00
status.c nl80211: Add support for EDMG channels 2019-08-21 11:07:35 +02:00
tdls.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-06-17 15:55:34 -07:00
tkip.c Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2019-07-08 20:57:08 -07:00
tkip.h Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2019-07-08 20:57:08 -07:00
trace_msg.h mac80211: Increase MAX_MSG_LEN 2019-03-29 11:20:36 +01:00
trace.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
trace.h mac80211: pass the vif to cancel_remain_on_channel 2019-07-26 13:08:28 +02:00
tx.c mac80211: pass internal sta to ieee80211_tx_frags() 2019-10-04 13:57:50 +02:00
util.c mac80211: IBSS: send deauth when expiring inactive STAs 2019-09-11 09:33:29 +02:00
vht.c mac80211: vht: add support VHT EXT NSS BW in parsing VHT 2019-09-11 09:13:03 +02:00
wep.c Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2019-07-08 20:57:08 -07:00
wep.h Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2019-07-08 20:57:08 -07:00
wme.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
wme.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
wpa.c mac80211: add IEEE80211_KEY_FLAG_GENERATE_MMIE to ieee80211_key_flags 2019-07-26 16:14:12 +02:00
wpa.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00