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wAP ac is slow with manager forwarding and high CPU

Posted: Sun Dec 09, 2018 6:32 am
by hooyao
Problem description:
wAP ac's 5G chip is QCA9880, which is suppose to deliver 70-80M/s data transfer speed with 2 chains(866M)
but with capsman's manager forwarding, wAP ac uses up CPU to deliver 42MB/s(330Mbps) to only 1 client. It's weird. The processing should be on capsman, there is no filter rules, nothing on wAP that eats CPU.
This performance is not reasonable for even a home AP. I'm wondering if there is some tricks to make the setup right.

My setup is:
x86 visualized RouterOS with L4 license as capsman on intel i3 5005(2 core 2.0G, 4 threads)
3x wAP ac with manager forwarding

testing bench:
8700k+z370+intel 9260ac

the wireless adapter can reach 866M without any problem via wAP ac, but the iperf test caps at 42M/s
capsman's CPU is like
capsman.PNG
wAP's CPU is like
capac.PNG
capsman's datapath is simple
Capture.PNG

Re: wAP ac is slow with manager forwarding and high CPU

Posted: Mon Dec 10, 2018 8:51 am
by Steveocee
Do you need to run the traffic locally through manager? The traffic is being tunneled back to the manager hence where the CPU usage is coming from, without tunneling you should get full speed.

Re: wAP ac is slow with manager forwarding and high CPU

Posted: Mon Dec 10, 2018 5:02 pm
by hooyao
Do you need to run the traffic locally through manager? The traffic is being tunneled back to the manager hence where the CPU usage is coming from, without tunneling you should get full speed.
Thank you for the info, but I tried local forwarding, the speed improves 2M/s, wifi and networking still eat up all the CPU.I notice there's no switch chip in wAP ac, the data forwarding between the Ethernet and WLAN has to go through CPU.

Re: wAP ac is slow with manager forwarding and high CPU

Posted: Mon Dec 10, 2018 11:28 pm
by mkx
Do you need to run the traffic locally through manager? The traffic is being tunneled back to the manager hence where the CPU usage is coming from, without tunneling you should get full speed.
Thank you for the info, but I tried local forwarding, the speed improves 2M/s, wifi and networking still eat up all the CPU.I notice there's no switch chip in wAP ac, the data forwarding between the Ethernet and WLAN has to go through CPU.
Data between ethernet and wifi will always go through CPU. And it seems that wifi drivers in ROS consume quite some CPU cycles, this seems to be the bottleneck in most situations. DL seems to be hit noticably worse than UL.

Re: wAP ac is slow with manager forwarding and high CPU

Posted: Sun Dec 16, 2018 11:16 pm
by anuser
~200Mbit/s on CAPSMAN forwarding enabled wAP ac with my old Sony Compact 802.11n smartphone connecting with 300Mbit/s.
Did you enable those:
/interface wireless set adaptive-noise-immunity=ap-and-client-mode wlan2
/interface wireless set adaptive-noise-immunity=ap-and-client-mode wlan1
Afterwards reenable Capsman Controller configuration

I see you have a current Intel AC wifi card in your laptop...

Re: wAP ac is slow with manager forwarding and high CPU

Posted: Mon Dec 17, 2018 12:25 am
by JohnTRIVOLTA
I have same issue ! With netbox 5 , 1 client /my laptop/ achieved max only 46 mbit/s when i transfer some file/s/ via ftp from my local nas. The laptop wireless adapter AR5BWB222 300/300 connectivity .
Image

Re: wAP ac is slow with manager forwarding and high CPU

Posted: Mon Dec 17, 2018 12:29 am
by mistry7
With Local forwarding and Fastpath active on bridge?
Only Hardware queue on WiFi Interfaces?

Re: wAP ac is slow with manager forwarding and high CPU

Posted: Mon Dec 17, 2018 4:57 pm
by hooyao
~200Mbit/s on CAPSMAN forwarding enabled wAP ac with my old Sony Compact 802.11n smartphone connecting with 300Mbit/s.
Did you enable those:
/interface wireless set adaptive-noise-immunity=ap-and-client-mode wlan2
/interface wireless set adaptive-noise-immunity=ap-and-client-mode wlan1
Afterwards reenable Capsman Controller configuration

I see you have a current Intel AC wifi card in your laptop...
I tried to set adaptive-noise-immunity=ap-and-client-mode, but it doesn't help, I'm afraid wap ac's problem is not noise interference, its cpu is bottlenecked.

Re: wAP ac is slow with manager forwarding and high CPU

Posted: Mon Dec 17, 2018 5:05 pm
by hooyao
With Local forwarding and Fastpath active on bridge?
Only Hardware queue on WiFi Interfaces?
localforwarding will increase 2M/s, with fast forward on, i give up, it should be the limit of wap ac.

and actually i mean 42MB/s, 330Mbps :)

Re: wAP ac is slow with manager forwarding and high CPU

Posted: Mon Dec 17, 2018 5:07 pm
by hooyao
I have same issue ! With netbox 5 , 1 client /my laptop/ achieved max only 46 mbit/s when i transfer some file/s/ via ftp from my local nas. The laptop wireless adapter AR5BWB222 300/300 connectivity .
Image
my wap ac can actually reach 330Mbps, it annoys me it's cpu bottlenecks it's speed. probably not the same issue :lol: