I'm using Ubuntu 18.10 with Linux 4.18.0 Kernel on Ryzen 1700 with NVidia GTX 1050 graphics card. The graphics driver is Nouveau.

I recently used UKUU to update the kernel to 4.19.2.

However, after the update, I faced random slow downs within 5 minutes to an hour after boot. It all goes well when suddenly the system just comes to almost a halt. The mouse pointer moves at a glacial speed and the caps lock light usually responds 30 seconds after being pressed.

I have reverted back to Kernel 4.18 and the problems have gone away.

I have checked the syslog but there is nothing out of the ordinary. The behaviour of kernel 4.19.2 is quite similar to memory leaks. But I have Conky installed, and I monitored memory and CPU quite keenly and there is nothing hogging resources.

How should I diagnose the problem?

As an aside, is it safe to clear existing logs in /var/log? Fresh logs might help me to zero in on the problem.

  • By upgrading to 4.19 (which is currently unsupported), you have become a tester. Thank you for contributing to Ubuntu by testing kernels, discovering the rough edges, and reporting bugs. However, kernel testing feedback should take place in the dev channels, not in support. Testing is recommended only for users experienced in diagnosing kernel problems and who can write good, useful, reproducible bug reports. To learn kernel-testing skills, start at wiki.ubuntu.com/KernelTeam – user535733 Nov 19 '18 at 23:58
  • Thanks. I have updated to 4.20rc3, which even as a release candidate seems much more stable than 4.19. I will try to diagnose the problem with 4.19 and try to report it. – Sabyasachi Mukherjee Nov 20 '18 at 0:14

How to diagnose a slow down, use top by running


Then determine what's using an ecessive amount of your processing power... Most of the time high cpu usage is caused by a bad usb cable that Linux can't configure. The other thing is heavy Web scripts, add on toolbars and multiple tabs open on a browser. At least in my experience those are the 2 main problems

After you've checked out your programs, look into your swappiness and tweak it just a little bit.

| improve this answer | |
  • Actually, I was monitoring memory usage and CPU activity. They were idle when the freezes started. Is there any GUI for tops, or conky script to integrate them in desktop? – Sabyasachi Mukherjee Nov 19 '18 at 22:35
  • Look closer right before it freezes, something is fluctuating and causes the system to freeze – user610658 Nov 19 '18 at 22:41

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