100% cpu usage on core 1 of AC88U

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Kouji71

New Around Here
Hello,

I've been using the Merlin firmware for my router for quite a while now, and just today I noticed that core 1 on my Asus AC88U is pegged at 100% all of the time, and restarting the router does not solve the issue. This must have started in the last week, because I updated to the newest firmware about a week ago, and the router was not having this issue.

Is there a way to see what is using the processor in the router (similar to task manager)? The only thing I've done recently was install Hyper-V on my home server and create a vm that runs bind9 and gnix to store copies of steam downloads so that they can be redownloaded from the server instead of the internet. However turning off the VM doesn't solve the issue, so I don't think that's the problem.

Any other info I can give to help out, please let me know. I'm not sure if it's affecting the performance of the router, but it is definitely running very warm.
 

Wagnard

Occasional Visitor
Hello,

I've been using the Merlin firmware for my router for quite a while now, and just today I noticed that core 1 on my Asus AC88U is pegged at 100% all of the time, and restarting the router does not solve the issue. This must have started in the last week, because I updated to the newest firmware about a week ago, and the router was not having this issue.

Is there a way to see what is using the processor in the router (similar to task manager)? The only thing I've done recently was install Hyper-V on my home server and create a vm that runs bind9 and gnix to store copies of steam downloads so that they can be redownloaded from the server instead of the internet. However turning off the VM doesn't solve the issue, so I don't think that's the problem.

Any other info I can give to help out, please let me know. I'm not sure if it's affecting the performance of the router, but it is definitely running very warm.
Same issue but with the latest official Asus firmware.
A little thing I found, the issue seems to happen after a wifi modification.
Rebooting the device does not work. What I mean is that the device fail to reboot, it will ignore the command (but the gui will still show as if it is rebooting but according to log, it's not rebooting.
Only way to fix the Cpu usage after a change is to physically power off / on the router.
 

DJsy

New Around Here
Hi. I get the same issue. Have tried stock firmware and Merlin. Both the latest stable. CPU1 locks at 100% after around a week of up time and only way to fix is to power off and on.

The CPU temp is high (80) and the Internet throughput is heavily restricted. Hard reboot resolves this.

Reboot via GUI says its working but actually doesn't.

Anyone else seen this or have any ideas?
 

bsdsource

Regular Contributor
Are you using the ASUS 3.0.0.4.384.10007 firmware that was just released ? The release notes indicated they fixed a high CPU loading issue.
 

DJsy

New Around Here
Currently it's on Merlin. Had the same issue as the Asus firmware it was on before that.

I'll give the stock firmware a try again (latest release) and see how that goes. I only switched to Merlin a week ago and prior to that it was on latest Asus firmware. If the version you mention is less than a week old then maybe it's fixed, otherwise it would have been the version I was running.
 

bsdsource

Regular Contributor
ASUS RT-AC88U Firmware version 3.0.0.4.384.10007 was released 2 days ago (Jan 2, 2018) so it' highly unlikely you were previously using this version. Also RMerlin hasn't merged this latest ASUS source code into his repository yet.

Please let us know if this new firmware resolves your issues. Would be good information.
 

DJsy

New Around Here
Brilliant thanks. I will get this firmware on today and monitor it over the next week or so to see if it happens again. I'll report back in a week. Fingers crossed!
 

Kbpr

New Around Here
Are you using the ASUS 3.0.0.4.384.10007 firmware that was just released ? The release notes indicated they fixed a high CPU loading issue.
Unfortunately, this issue is not fixed. I am using this newest Asus version and am still seeing high CPU. My core 2 stays mostly at 100%, even when idle. Core 1 spikes as much as 100% but in general stays at under 10% when idle.
 

curlysir

Occasional Visitor
I have an RT-AC3100 that recently started doing this and the only solution I have found is as others have stated is to do a power off/on cycle. I had to do it twice as it was core 2 the first time and core 1 the 2nd time a day later. After doing this for both cores it has been normal for 3 days.
 

dsring

Regular Contributor
I have an RT-AC3100 that recently started doing this and the only solution I have found is as others have stated is to do a power off/on cycle. I had to do it twice as it was core 2 the first time and core 1 the 2nd time a day later. After doing this for both cores it has been normal for 3 days.
Same problem here with my RT-AC88U. It just started recently. The Core 1 CPU usage pegs at 100% after any router setting change that causes the 2.4GHz wireless radio to restart. It severely slows down the network. I can get it back to normal by powering cycling the router. It is consistent across all 382 and 384 series firmware versions.
 

HeadBanger

Regular Contributor
CPU 1 maxes out for me too on RT-AC68U. It seems to be caused by AiProtection and the CPU usage is accelerated by IPTV to the point that the router eventually freezes and requires a reboot. If I turn off AiP it is fine - the CPU usage is back down and no router freezes.

I've raised it in a few threads here already and emailed ASUS so hopefully someone there will take notice soon.

HB
 

dsring

Regular Contributor
CPU 1 maxes out for me too on RT-AC68U. It seems to be caused by AiProtection and the CPU usage is accelerated by IPTV to the point that the router eventually freezes and requires a reboot. If I turn off AiP it is fine - the CPU usage is back down and no router freezes.

I've raised it in a few threads here already and emailed ASUS so hopefully someone there will take notice soon.

HB
In my case, AI Protection is not enabled.
 

bsdsource

Regular Contributor
There's a lot of complaints about this but I don't see any definitive reason as to why this is happening.
 
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RMerlin

Asuswrt-Merlin dev
There's a lot of complaints about this but I don't see any definitive reason as to why this is happening.

Might be because despite my repeated responses, nobody so far seems to have taken the time to run "top" to determine WHAT is using the CPU.
 

bsdsource

Regular Contributor
Good point RMerlin. Yeah using the top command should point out the problem. So lets try to isolate this issue so the next ASUS firmware release can address the high CPU load issue.

To help isolate the exact cause I would suggest providing the following information in your posts:
  1. SSH or telnet into your router and use the "top" command from the command prompt. This will show you the CPU load being used by every service running on your router.
  2. Are you updating firmware using the webgui or restoration tool?
  3. Are you resetting your router to factory defaults after firmware install?
  4. Are you importing your saved setting back into the router?
  5. Which services are you using? Guest network, AI Protection, Etc.
  6. Is this happening with a fresh firmware install after making a simple settings change?
Those who are experiencing this issue please provide at least the output from the "top" command.
 
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MWAC

New Around Here
Hello All. I'm new here. I've been experiencing exact problem past few months. Hope this help.
CPU.png
 
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bsdsource

Regular Contributor
Thanks MWAC for taking the time to provide a screenshot. acsd seems to be utilizing too much CPU in your particular case. If we can get some others to post their top output we might be able to narrow the problem down specifically to acsd.
 

dsring

Regular Contributor
Might be because despite my repeated responses, nobody so far seems to have taken the time to run "top" to determine WHAT is using the CPU.
I did see the previous request to issue the “top”command. I was going to issue the top command, but was enable to do so. The thing that triggers the 100% CPU usage is a change in the 2.4 GHz WiFi settings that causes the 2.4 GHz radio to restart. Once the CPU usage hits 100%, I lose 2.4 GHz WiFi and the router GUI is slow to respond. I can enable telnet, but I cannot log into the router through telnet. It will say unable to connect or something to that effect. The only way to restore functionality to the router is to power cycle it.
 

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