[FS#563] cake qdisc high cpu usage on tp-link 841n
LEDE Bugs
lede-bugs at lists.infradead.org
Mon Feb 27 14:19:26 PST 2017
A new Flyspray task has been opened. Details are below.
User who did this - Martin Tippmann (glycoknob)
Attached to Project - LEDE Project
Summary - cake qdisc high cpu usage on tp-link 841n
Task Type - Bug Report
Category - Base system
Status - Unconfirmed
Assigned To -
Operating System - All
Severity - Low
Priority - Very Low
Reported Version - Trunk
Due in Version - Undecided
Due Date - Undecided
Details - So, I had this crazy idea to just make cake the default qdisk after seeing the battlemesh presentation. Now we are seeing high spikes in CPU usage after some time - the peaks appear to be of periodic nature. I only have some nmeter plots (basically vmstat/sar with dots - it's a busybox applet) - the high load immediatly vanishes after switching the qdiscs back to fq_codel.
I've seen this on 2 841n routers one only using ap+ibss mode the other having wan+lan+ap+ibss+tap interfaces with cake running. Both also run a bridge for the AP.
Is the high system cpu usage expacted behavoir? cake qdisc is just using defaults:
This script does the activation:
# cat /etc/hotplug.d/iface/00-cake-qdisc
#!/bin/sh
case "$ACTION" in
ifup)
grep -q '^sch_cake' '/proc/modules' && {
command -V tc > /dev/null || return
tc qdisc replace dev "$DEVICE" root cake
}
;;
esac
# vim: set filetype=sh ai noet ts=4 sw=4 sts=4 :
The results (1 line = 1 second):
root at weimarnetz-188:~ :) nmeter '%40c wlan: %[nbr-vap] ibss: %[nwlan0]'
cake
SSSSSSSSUii............................. wlan: 8856 756 ibss: 4026 9162
SSSSSSSSSSSSSSSSSSSSU................... wlan: 44k 1736 ibss: 8726 49k
SSSSSSSi................................ wlan: 58k 2130 ibss: 5974 62k
SSSUUUUi................................ wlan: 58k 1296 ibss: 15k 68k
SSSSSSSSi............................... wlan: 49k 2532 ibss: 5298 53k
SSSSSSSSSSiii........................... wlan: 45k 2082 ibss: 8282 49k
SSSSSSSSSSSSSSSSSSSSSSU................. wlan: 39k 1794 ibss: 14k 45k
SSSSSSSSSSSSSSUi........................ wlan: 34k 2112 ibss: 11k 29k
SSSSSSSSSSSSSSSSSSSSSUUi................ wlan: 47k 2172 ibss: 7614 60k
U....................................... wlan: 58k 2934 ibss: 7496 61k
SSUi.................................... wlan: 53k 1944 ibss: 9.8k 58k
SSSSSSSSSSSSSSSSSSU..................... wlan: 47k 1698 ibss: 6552 51k
SSSSSSSSSSSSSUi......................... wlan: 57k 2704 ibss: 9.9k 62k
UUUiii.................................. wlan: 57k 1512 ibss: 8956 63k
SSSSSSSSSSSSSSSSSSSSSSSSii.............. wlan: 77k 4010 ibss: 17k 85k
SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSUii wlan: 6400 318 ibss: 450 6784
SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSi wlan: 47k 1296 ibss: 12k 55k
SUUii................................... wlan: 49k 2542 ibss: 5604 53k
SSSSSSSSUUi............................. wlan: 56k 2354 ibss: 10k 62k
SSSSSSSSSSSSSSSSSSSSSi.................. wlan: 58k 1926 ibss: 11k 64k
SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSi wlan: 59k 2464 ibss: 22k 67k
SSSSSSSSSSSSSSUi........................ wlan: 41k 972 ibss: 10k 50k
SUi..................................... wlan: 44k 2132 ibss: 6310 47k
SUUi.................................... wlan: 52k 1642 ibss: 11k 58k
SSSSSSSSSSSSSSSSSSSSSSUi................ wlan: 54k 3826 ibss: 11k 60k
SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSUi wlan: 44k 1482 ibss: 6580 48k
SSSSSSSSSSSSSSSSSSSSSSSSSSSSSi.......... wlan: 32k 2396 ibss: 9732 38k
SSSSSSSSSSSSSSSSUUi..................... wlan: 18k 1164 ibss: 6888 20k
SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSUi... wlan: 37k 864 ibss: 13k 46k
SSSSSSSSSSSi............................ wlan: 57k 2112 ibss: 4166 60k
SSi..................................... wlan: 56k 1746 ibss: 11k 62k
SSSSSSSSSSSSSSSSSSSSi................... wlan: 43k 28k ibss: 39k 48k
SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSUU....... wlan: 15k 18k ibss: 25k 21k
SSSSSSSSSSSSSSSSUiiii................... wlan: 42k 255k ibss: 261k 52k
SUiiii.................................. wlan: 39k 393k ibss: 398k 54k
SSSSSSSSSSSSSSSSSSSSSSSSiii............. wlan: 26k 244k ibss: 251k 33k
SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSii........ wlan: 44k 86k ibss: 93k 54k
SSSSSSSSSSSSSSSSSSSSSSSSSSSUUii......... wlan: 27k 33k ibss: 41k 33k
SSSSSUiii............................... wlan: 54k 36k ibss: 40k 60k
SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSii wlan: 30k 46k ibss: 52k 35k
SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSi wlan: 23k 13k ibss: 20k 26k
SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSUii.... wlan: 53k 31k ibss: 40k 66k
SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSU......... wlan: 31k 18k ibss: 29k 35k
SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSi wlan: 13k 1262 ibss: 8370 16k
SSSSSSSSSSSSUi.......................... wlan: 46k 35k ibss: 54k 63k
SU...................................... wlan: 53k 87k ibss: 93k 59k
SSSSSSSSSSUUi........................... wlan: 43k 23k ibss: 32k 50k
SSSUUUiii............................... wlan: 46k 164k ibss: 172k 54k
SSSSSSSSSUiii........................... wlan: 48k 245k ibss: 250k 59k
SSSSSSSSSSSSSSS......................... wlan: 38k 5959 ibss: 10k 44k
SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSi wlan: 38k 1838 ibss: 9944 41k
SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSi wlan: 25k 1344 ibss: 2774 25k
SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS wlan: 43k 2442 ibss: 10k 44k
SSSSSSSSSSSSSSSSSSSSUUii................ wlan: 59k 1968 ibss: 11k 73k
Si...................................... wlan: 60k 2354 ibss: 10k 67k
SU...................................... wlan: 57k 1680 ibss: 11k 63k
Siii.................................... wlan: 51k 3560 ibss: 8042 54k
SSSSSSSSSSSi............................ wlan: 50k 1080 ibss: 14k 58k
SSSSSSSSSSSSSUU......................... wlan: 53k 2548 ibss: 13k 59k
SSSSSSSSSSSSi........................... wlan: 46k 2309 ibss: 9093 52k
SSSSSSSSSSSSSSSSSSSSi................... wlan: 83k 3816 ibss: 14k 91k
SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSi........ wlan: 25k 3210 ibss: 5668 26k
SSSSSSSSSSSSSSSSSSSSSSSUii.............. wlan: 53k 2478 ibss: 11k 59k
SSSSSSSSSSSSSSSSSSSSSSSSSUi............. wlan: 15k 1308 ibss: 8142 20k
SSUUii.................................. wlan: 799 607 ibss: 11k 5339
SUi..................................... wlan: 1449 1436 ibss: 11k 9399
SSSSSSSSSSSSSSSSSSSSSSSSSSSSU........... wlan: 240 2738 ibss: 10k 3224
SSSSSSSSSU.............................. wlan: 132 66 ibss: 10k 4804
UUi..................................... wlan: 320 347 ibss: 11k 6020
-----> fq_codel
S....................................... wlan: 0 0 ibss: 8664 3682
SSSSSSSSSU.............................. wlan: 0 0 ibss: 9022 6566
SS...................................... wlan: 703 6076 ibss: 14k 3565
S....................................... wlan: 2971 1862 ibss: 8554 7219
SUi..................................... wlan: 0 0 ibss: 7810 3732
SSUUi................................... wlan: 0 0 ibss: 8440 2920
SSii.................................... wlan: 1449 1436 ibss: 10k 7771
Ui...................................... wlan: 0 0 ibss: 8068 3258
Ui...................................... wlan: 0 0 ibss: 7910 3614
SSUi.................................... wlan: 252 185 ibss: 12k 5022
SUi..................................... wlan: 4742 1368 ibss: 9.8k 10k
SU...................................... wlan: 0 0 ibss: 11k 4646
Ui...................................... wlan: 0 0 ibss: 15k 5802
SS...................................... wlan: 0 0 ibss: 6918 3742
SU...................................... wlan: 122 2576 ibss: 4978 404
SSUii................................... wlan: 0 0 ibss: 8856 5890
SU...................................... wlan: 1449 1436 ibss: 6598 4791
SU...................................... wlan: 41 54 ibss: 4234 2101
UUii.................................... wlan: 0 0 ibss: 12k 5438
SUi..................................... wlan: 280 239 ibss: 7599 1644
U....................................... wlan: 0 0 ibss: 5962 3606
U....................................... wlan: 0 0 ibss: 10k 5502
SU...................................... wlan: 0 0 ibss: 14k 7486
Ui...................................... wlan: 0 0 ibss: 14k 5030
SU...................................... wlan: 0 0 ibss: 7930 4702
Ui...................................... wlan: 799 606 ibss: 10k 5400
SSSSSSSSSSSSSU.......................... wlan: 1449 1436 ibss: 9936 5653
S....................................... wlan: 0 0 ibss: 5818 2964
SU...................................... wlan: 0 0 ibss: 11k 7547
SU...................................... wlan: 252 185 ibss: 6264 3875
Ui...................................... wlan: 4159 995 ibss: 8313 8409
U....................................... wlan: 0 0 ibss: 3912 1240
SU...................................... wlan: 0 0 ibss: 4600 3784
S....................................... wlan: 122 2604 ibss: 9706 3374
SUUUi................................... wlan: 0 0 ibss: 13k 6328
U....................................... wlan: 0 0 ibss: 10k 6940
ii...................................... wlan: 1504 1589 ibss: 8605 4736
SUUi.................................... wlan: 108 0 ibss: 13k 8516
SUi..................................... wlan: 5241 28k ibss: 32k 9431
SSUUi................................... wlan: 9.7k 24k ibss: 33k 14k
SUi..................................... wlan: 743 456 ibss: 14k 7591
U....................................... wlan: 0 0 ibss: 2212 2732
SSSSSSSSSSU............................. wlan: 0 0 ibss: 9750 6434
........................................ wlan: 4585 492 ibss: 4616 6971
SUi..................................... wlan: 326 1155 ibss: 11k 4874
Si...................................... wlan: 0 0 ibss: 2330 214
Si...................................... wlan: 4336 3047 ibss: 18k 11k
SUi..................................... wlan: 100 0 ibss: 9838 5264
S....................................... wlan: 0 0 ibss: 14k 6298
SSSU.................................... wlan: 644 511 ibss: 6719 4294
SUii.................................... wlan: 0 0 ibss: 13k 6274
S....................................... wlan: 0 0 ibss: 6822 1738
U....................................... wlan: 0 0 ibss: 4790 1730
Ui...................................... wlan: 124 110 ibss: 5518 3544
SU...................................... wlan: 229 42 ibss: 8218 4972
Si...................................... wlan: 1000 607 ibss: 4750 2432
........................................ wlan: 1650 1436 ibss: 8372 5635
UUi..................................... wlan: 201 0 ibss: 9418 5422
Ui...................................... wlan: 0 0 ibss: 14k 7438
SSUi.................................... wlan: 3268 1862 ibss: 14k 9690
SUU..................................... wlan: 0 108 ibss: 9030 4918
SSi..................................... wlan: 80 108 ibss: 9442 5162
Ui...................................... wlan: 41 54 ibss: 9768 4757
Sii..................................... wlan: 58 104 ibss: 5570 3562
UU...................................... wlan: 0 0 ibss: 7098 4134
SU...................................... wlan: 0 0 ibss: 8142 2818
S....................................... wlan: 2941 2271 ibss: 7081 6303
SUi..................................... wlan: 315 0 ibss: 8524 3738
Ui...................................... wlan: 1309 757 ibss: 10k 7143
SUU..................................... wlan: 1450 428 ibss: 7150 5470
SUi..................................... wlan: 3187 8952 ibss: 16k 7107
U....................................... wlan: 4559 2197 ibss: 7959 8811
Ui...................................... wlan: 5564 2171 ibss: 8323 9118
i....................................... wlan: 11k 41k ibss: 50k 18k
root at weimarnetz-188:~ 8( cat /tmp/sysinfo/model
TP-Link TL-WR841N/ND v11
root at weimarnetz-188:~ :) cat /etc/os-release
NAME="weimarnetz"
VERSION="SNAPSHOT, Reboot"
ID="weimarnetz"
ID_LIKE="lede openwrt"
PRETTY_NAME="weimarnetz Reboot SNAPSHOT"
VERSION_ID="snapshot"
HOME_URL="http://lede-project.org/"
BUG_URL="http://bugs.lede-project.org/"
SUPPORT_URL="http://forum.lede-project.org/"
BUILD_ID="v0.10.0-dirty+lede-r3598-eb09d79c16"
LEDE_BOARD="ar71xx/generic"
LEDE_ARCH="mips_24kc"
LEDE_TAINTS="no-all busybox"
LEDE_DEVICE_MANUFACTURER="LEDE"
LEDE_DEVICE_MANUFACTURER_URL="http://lede-project.org/"
LEDE_DEVICE_PRODUCT="weimarnetz"
LEDE_DEVICE_REVISION="v0"
LEDE_RELEASE="weimarnetz Reboot SNAPSHOT v0.10.0-dirty+lede-r3598-eb09d79c16"
(this is basically stock release just with a versioning patch and the symbols added:
CONFIG_KERNEL_KALLSYMS=y
CONFIG_BUSYBOX_CUSTOM=y
CONFIG_BUSYBOX_CONFIG_MKSWAP=n
CONFIG_BUSYBOX_CONFIG_SWAPONOFF=n
CONFIG_BUSYBOX_CONFIG_MKPASSWD=y
CONFIG_BUSYBOX_CONFIG_ARPING=y
CONFIG_BUSYBOX_CONFIG_NMETER=y
CONFIG_PACKAGE_MAC80211_MESH=n
CONFIG_TARGET_SQUASHFS_BLOCK_SIZE=256
CONFIG_STRIP_KERNEL_EXPORTS=y
More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=563
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