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100% CPU usage after uninstalling

Posted: Fri Mar 20, 2020 3:47 pm
by mcsorangejuice
Hi All,

Yesterday I downloaded and installed fahclient, fahcontrol, and fahviewer on my machine running Linux Mint 19.3 (dualbooted with Windows 10). I started folding at 50% CPU capacity (no GPU) and allowed my computer to sleep. I came back later and the computer was not responsive (computer running but screen black and mouse/keyboard input did not wake machine up) and so I did a shutdown using the power button. Then I rebooted into Mint and my CPU was working very hard. I didn't check the usage at the time but my cooler was working 100%. I thought it probably has something to do with FAH so I uninstalled all three programs, however it now seems as though my CPU is working at 100% on all cores (Ryzen 2700x) immediately when I log into Mint now. The system monitor shows no processes using CPU resources. After a couple minutes my machine shuts down (I assume due to some CPU temperature safety measure).

Does anyone have advice for what could be causing this and how to fix it? I am not a great user of Linux and have just started learning so there may be something obvious I am missing. If there's any other information I can provide to help diagnose the issue please let me know. Thanks for your time.

Edit: I ran "inxi -t c5" command in the terminal to see the culprit and it showed "1:CPU 1395% command: fahcore_a7 pid: 1430"
I killed process 1430 using "sudo kill 1430", but then another instance of fahcore_a7 showed up under a different pid, this repeats over and over.

Re: 100% CPU usage after uninstalling

Posted: Fri Mar 20, 2020 4:08 pm
by Jesse_V
Hi, and welcome to the forums. This is definitely odd.

In Mint, there should be a System Monitor tool that can let you see what processes are using high CPU. You can also see this by opening a terminal and typing "htop" or "top". Do any of them say "FAHCore" or "FAHClient", after you uninstalled? How did you uninstall it?

I'm on Kubuntu at the moment and the tools are a bit different, but let me know what you see.

Re: 100% CPU usage after uninstalling

Posted: Fri Mar 20, 2020 4:17 pm
by mcsorangejuice
Thanks Jesse_V,

Maybe the uninstall was the problem. I just searched for all three applications, right clicked on the gui icon, and selected uninstall. I did this in no particular order as I was mildly panicking since this machine is needed for my work at the moment. Is there any way to search for files that perhaps did not get cleanly deleted using that uninstall method? Also I used "top" and yes, there is a line "PID: 2193 USER: fahclient ...... %CPU 1498 ... COMMAND: FahCore_a7. If I try to kill that process it works, but then a new one appears with a different PID. There are also sometimes as many as 3 fahclient processes at once.

Re: 100% CPU usage after uninstalling

Posted: Fri Mar 20, 2020 4:25 pm
by Jesse_V
It looks like the Folding@home software is still installed. You should be able to remove it with a command like "sudo apt-get remove fahclient fahcontrol" and that should clear it.

Edit: go with what Bruce said first.

I will also mention that you can set the software to run when you're away, when the computer is idle, or when you want it to run. I do this myself because I want to help when I can, but I also need full power of the computer at certain times.

Re: 100% CPU usage after uninstalling

Posted: Fri Mar 20, 2020 4:26 pm
by bruce
FAHCore_a7 is the app that uses CPU resources to compute the assigned WUs. (It's supposed to run at a low-priority, high "nice" 100%) but it's also telling you that you attempt to uninstall was unsuccessful.

Do you still have FAHControl? If so, click on the FINISH button. That will drain those precious WUs that have been assigned to you as they finish. Then we can work with you on the uninstall.

Re: 100% CPU usage after uninstalling

Posted: Fri Mar 20, 2020 4:36 pm
by mcsorangejuice
Thanks a lot to both of you. Using "sudo apt-get remove fahclient fahcontrol" worked. Apparently fahcontrol was not installed but fahclient was. It's possible that when I was rushing to uninstall the programs I forgot about fahclient, or maybe something weird happened where I uninstalled in the wrong order, or fahclient was already running and therefore did not uninstall successfully. All seems to be back to normal.

Re: 100% CPU usage after uninstalling

Posted: Fri Mar 20, 2020 4:42 pm
by bruce
FAHClient was running. (It's what kept restarting FAHControl_a7).