100% cpu usage on core 1 of AC88U

[Haraldinho]

I am currently doing an experiment on my AC-5300, I disabled SmartConnect (which is mandatory if you want to set manual control channels) and I set all control channels to manual. If I understand the workings of the ACSD process correct, this process is meant to search for the best automatic channel. So by setting control channels to manual, it should not be used hence it cannot go crazy on the CPU.
I will let you guys know if this solves my CPU usage issue. So far so good.

 

[Haraldinho]

For all you suffering from the 100% CPU issue: I can state that my issue is resolved now. After almost 1 week the CPU % is still normal, usually it would go crazy within one day.
So: if your CPU is going crazy without a clear reason, SSH into your router, and run the top command. If you see that the ACSD process is the process consuming all the CPU power, then try to set your control channels manually and let us know in this thread if it resolved your issue.

 

[davidedg]

Hi,

I'm on RT-AC68U here, asuswrt-merlin, latest stable.
No cpu problems with 380.x series
I factory reset and upgraded to 384.x, reconfiguring from scratch.
I have an USB-3 stick in usb-3 port, formatted in ext4 and entware-ng installed (I use the "netdata" package)
Sometimes, after some 1~2 days, my GUI shows consistent CPU 100% for CORE-1

top seems to say that there is consistent NIC usage?

But I am barely using my Internet line: I'm at 5~7 Mbps right now - and if go to fast.com (130Mbps peak), I can see only that CPU goes slightly above 1% (nic stays at 49.4%)

How can I troubleshoot more ?

I suspect it might be related to USB-3 - but I can't find an evidence of that - I might try for 1 or 2 weeks to unplug the usb key ?

Bye TY!

 

[BSOD2600]

I'm nearly in the same boat as davidedg.

RT-AC87U on 384.5.
One core is constantly at 100%. Reboots have not helped.

Wifi 2.4 and 5 ghz are disabled (use an external AP).
top shows nic is consuming about 50%, with no other processes using much of anything.

 

[JohnSmith]

I have the exact same issue with my AC3100 on 384.5. My system has been up for 16 days with no indications of any issues so far (minor ones), except the Core 1 CPU showing using 100%, but TOP shows it barely being used.

This is also after I defaulted the router, initialized it, and reset up values and settings from scratch.

 

[TikiG]

I had an issue yesterday. RT AC66U_B1 , 384.4_2, Qos Script enabled.

Router appeared to be functioning normally. However, when I tried to login, I got page unavailable error. Finally tried :8443 and was able to login. CPU 2 was at 100%.

Found this thread and read it. SSH attempts failed and would not give me the ability to login.

Tried reboot via web console. No effect. Only a hard power reboot fixed everything.

24 Hrs. later , no issues with CPU and SSH top continues to look normal.

Note: I have always used manual control channels on the wifi.

Not sure what triggered it...

 

[BSOD2600]

Unplugged router for several minutes (troubleshooting cable modem issues), which so far has cleared up this problem. Weird.

 

[davidedg]

I have the exact same issue with my AC3100 on 384.5. My system has been up for 16 days with no indications of any issues so far (minor ones), except the Core 1 CPU showing using 100%, but TOP shows it barely being used.

This is also after I defaulted the router, initialized it, and reset up values and settings from scratch.

Sometimes I had the same problems of TikiG (unable to SSH and HTTP unresponsive), but it's rare (instead the CPU-100% in GUI and top showing no particular process is very common).

Interestingly enough, you too seem to have an USB key attached.
Since previous 24th of May - I disconnected USB key (mine is a usb 3 though) and so far I have had no problems.

I'm trying to "trigger" the problem with usb disconnected too (for example, by applying different wifi settings), but no problems so far.
@ALL: can we find a common suspect being an USB stick ? - Or someone has same symptoms (gui: 1 core 100%, but top showing no process hogging) without USB stick?

@RMerlin: I can do advanced diagnostics/tests if you ask.

Bye!

 

[kfp]

You are reading top wrong. nic is 0%, 50% is idle and 50% is io. I bet you have something plugged to the USB port, start troubleshooting there.

 

[davidedg]

You are reading top wrong. nic is 0%, 50% is idle and 50% is io. I bet you have something plugged to the USB port, start troubleshooting there.

-- you're damn right -- definitely makes sense with my suspects (usb) now !

I will try to re-plug the USB stick - and try to identify the process stressing it with

watch -n1 -d "ps wT | awk '{if (\$4==\"D\") {print \$0}}'"​

Thank you.

 

[agilani]

I'm nearly in the same boat as davidedg.

RT-AC87U on 384.5.
One core is constantly at 100%. Reboots have not helped.

Wifi 2.4 and 5 ghz are disabled (use an external AP).
top shows nic is consuming about 50%, with no other processes using much of anything.

I had the same issue and asked earlier. Looks like io is taking up most of your cpu cycles. My best guess in my case was that i have debug logging turned on and every once inawhile i get a dhcp broadcast storm which overloads the disks. Only a hard reboot resolved the problem.

 

[TikiG]

In my case particular instance, I have no USB key.

Never have used one in that router.

 

[kfp]

In my case particular instance, I have no USB key.

Never have used one in that router.

It’s strange that you can login through web but not ssh. You could save the syslog to jffs so that next time it happens you have something to look at after a power cycle.

 

[TikiG]

In my case I wasn't able to log in using the normal http. Eventually tried the https:8443 and it let me in.

Made me wonder as well, perhaps the https process kicked over to the idle core? Not sure.

 

[Stpijb]

Hey guys, thanks for the awesome work you put into this firmware. I just purchased an ac88u and installed the latest and greatest stable version. I did find that core 1 was using 70-100% while core 2 sat almost completely idle. I couldn't even login with putty to see what was going on. I did try a lot of things and rebooted after each method to fix. First i turned wps off didn't fix it. Turned qos off didn't fix. Turned smart connect off didn't fix. Turned guest network off didn't fix. Turned 5ghz off didn't fix. Turned 2.4ghz off didn't fix.

After all of this I downloaded the legacy firmware reset the router and installed the latest legacy version. Usage dropped to 1% across both cores. I didn't see memory usage ever go up. So something is acting up with the stable versions.

 

[kfp]

@Stpijb Do you have anything plugged-in to the USB ports?

 

[netguru]

Same here, RT88U, no USB in use (never ever), Core working 50% ACSD in SSH "top" ...

Toggle WPS helps ...

 

[Stpijb]

@Stpijb Do you have anything plugged-in to the USB ports?

Nothing. I use wdcloud over ethernet and it was unplugged during testing.

 

[RMerlin]

Same here, RT88U, no USB in use (never ever), Core working 50% ACSD in SSH "top" ...

Toggle WPS helps ...

Set a fixed channel instead of using Auto.

 

[Stpijb]

Set a fixed channel instead of using Auto.

Tried that also. Set 2 and 157. Made it worst with core 1 stock at 100.