AX86U sudden high CPU usage

[Markfree]

AX86U - 388.2_2

Recently, I have been experiencing high CPU usage on my router, which has been causing connectivity issues.
When that happens the DNS service (Adguard Home) stops responding. Additionally, I am unable to open an SSH connection to the router.

Occasionally, I can access the router's web interface using its IP address, allowing me to observe the high CPU usage.

ScMerlin, displays the running processes, but none of them show significant CPU utilization.
However, there are instances when the web interface fails to load altogether.
Strangely, these problems often occur during periods of low network activity.

When attempting to reboot the router through the web interface, it becomes unresponsive and gets stuck. The only way to restart it is by physically power cycling the device.

I would appreciate any suggestions or tips you may have for diagnosing this issue.

 

[Viktor Jaep]

AX86U - 388.2_2

Recently, I have been experiencing high CPU usage on my router, which has been causing connectivity issues.
When that happens the DNS service (Adguard Home) stops responding. Additionally, I am unable to open an SSH connection to the router.

Occasionally, I can access the router's web interface using its IP address, allowing me to observe the high CPU usage.
View attachment 50907
ScMerlin, displays the running processes, but none of them show significant CPU utilization.
However, there are instances when the web interface fails to load altogether.
Strangely, these problems often occur during periods of low network activity.

When attempting to reboot the router through the web interface, it becomes unresponsive and gets stuck. The only way to restart it is by physically power cycling the device.

I would appreciate any suggestions or tips you may have for diagnosing this issue.

Other than AdGuardHome, what other scripts are you running? Putting those in your tagline helps us do a little more troubleshooting on the front-end... I know SCMerlin might show the same thing, but have you looked at using htop to do some better sorting of tasks that are taking up lots of CPU/RAM etc?

The screenshot provided looks like something you'd see directly after a reboot... correct? Typically, when AdGuardHome starts, it is pretty heavy on the CPU and RAM will eventually level off in the 900's if I'm not mistaken?

 

[Morris]

If you have swap on a USB key, try a different one.

 

[Jeffrey Young]

Install top and run it when the router is showing such high usage and see what it has to show for processes using all your cpu power

 

[Martinski]

Install top and run it when the router is showing such high usage and see what it has to show for processes using all your cpu power

You probably meant the 'htop' utility via Entware. The 'top' utility (/usr/bin/top) is already installed in AsusWRT f/w and included in Asuswrt-Merlin f/w as well.

 

[Jeffrey Young]

You probably meant the 'htop' utility via Entware. The 'top' utility (/usr/bin/top) is already installed in AsusWRT f/w and included in Asuswrt-Merlin f/w as well.

Yeah - I loose track of what is pre-installed and what is not.

I was still thinking top, but htop would work too.

 

[ColinTaylor]

I was still thinking top, but htop would work too.

But he said:

Additionally, I am unable to open an SSH connection to the router.

 

[Jeffrey Young]

But he said:

Missed that. That would be a problem.

 

[Markfree]

I use the following addons:

• scribe v3.1.2
• connmon v3.0.2
• ntpMerlin v3.4.5
• scMerlin v2.4.0
• uiScribe v1.4.5
• YazDHCP v1.0.5
• AdGuardHome v1.6.1
• Disk check script
• Reboot scheduler Sat @ 4:00

After a fresh restart, I opened HTOP, and everything seemed fine. However, after a while, it started failing again.
Since the SSH connection was still open, I managed to launch HTOP again.
Essentially, the CPU load was very high.

When I attempted to stop the AdGuard service, it simply would not stop.
Only after terminating AdGuard's process did the CPU load decrease, allowing me to regain Internet access.

Nevertheless, the load remained high, averaging around 10 for 1m. Additionally, when I tried to open AdGuard's log file, it became stuck. So, I had to restart it again.

I don't have a swap partition. However, I recently experienced a failed USB flash drive, so I switched to another one.
It is functioning, but it's not ideal. Tomorrow, I'll acquire a new drive that I know is reliable. Another reset...

 

[kernol]

Suggest you carefully read through this thread ...
https://www.snbforums.com/threads/adguardhome-v1-6-1-release.85191/

With that fleet of " Addons" - you would be well advised to add a swap file to a reliable USB .. especially for Adguard as noted in the thread above.

 

[Markfree]

Suggest you carefully read through this thread ...
https://www.snbforums.com/threads/adguardhome-v1-6-1-release.85191/

With that fleet of " Addons" - you would be well advised to add a swap file to a reliable USB .. especially for Adguard as noted in the thread above.

I use AdGuard with 38 lists that contain approximately 500K+ rules, and I haven't experienced major issues so far.
AdGuard updates these lists daily, and it consistently works well. Additionally, I don't utilize swap.

I have been using this "fleet" of addons for a long time without encountering any major problems.
Also, I have another AX86U with the same configuration at another site and it does not present any issue, which bugs me even more.

Only recently I've started to notice this CPU issue, and I haven't been able to identify the root cause yet.

I appreciate all the feedback and will reply as soon as I have new information.

 

[kernol]

I use AdGuard with 38 lists that contain approximately 500K+ rules, and I haven't experienced major issues so far.
AdGuard updates these lists daily, and it consistently works well. Additionally, I don't utilize swap.

I have been using this "fleet" of addons for a long time without encountering any major problems.
Also, I have another AX86U with the same configuration at another site and it does not present any issue, which bugs me even more.

Only recently I've started to notice this CPU issue, and I haven't been able to identify the root cause yet.

I appreciate all the feedback and will reply as soon as I have new information.

The version of Adguard that you are using [version 1.6.1] was modified and released on 25 May 2023 ... with this caveat ...

... The tradeoff to the memory optimization improvement is that AdGuardHome will require to use more CPU when processing lists and performing tasks. ...

Which is the reason I drew your attention to the thread. You have a pretty impressive set of lists to be processed ... so just maybe the high cpu usage only recently experienced [perhaps after the update?] may be the cause of your problem??

 

[Markfree]

I'm not sure why, but it was the USB drive, after all.
After changing the USB drive for a better one, using the same configuration and addons, I had no more issues.

Now the CPU is stable.

 

[L&LD]

Until you use an SSD in an external enclosure via USB, you'll most likely continue to have issues.

 

[Strud]

I was about to state exactly the same.
Was experiencing strange reboots, internet freezez and failures of multiple USB keys until I have decided to use an older SSD, all problems are well gone since then.

 

[zer0bitz]

I was about to state exactly the same.
Was experiencing strange reboots, internet freezez and failures of multiple USB keys until I have decided to use an older SSD, all problems are well gone since then.

Same here. Used to have massive problems always when used USB keys. I had a spare M.2 SSD so I bought a USB adapter enclosure for it and never had a problem after that.

 

[fearz]

So for those who are having the same issue (100% CPU usage) after the last ADGuard update and no SSD option, everything was working fine prior to that update, what shall we do?

Im using a USB flash drive to USB 2.0 on AC5300 with 5GB swap.

 

[Kingp1n]

So for those who are having the same issue (100% CPU usage) after the last ADGuard update and no SSD option, everything was working fine prior to that update, what shall we do?

Im using a USB flash drive to USB 2.0 on AC5300 with 5GB swap.

Maybe try something like this:

Post in thread 'USB recommendations for Diversion / Skynet?' https://www.snbforums.com/threads/usb-recommendations-for-diversion-skynet.84828/post-838985

 

[Ubimo]

How do I install htop and get this diagram?

 

[kernol]

How do I install htop and get this diagram?

Assuming you have Entware installed from "amtm" comandline menu which ships within Merlinware ... use this command from SSH terminal ..

opkg install htop