On Thu, May 18, 2017 at 1:04 PM, Pete Biggs <pete at biggs.org.uk> wrote: > >> >> kernel: BUG: soft lockup - CPU#5 stuck for 67s! [khungtaskd] >> kernel: BUG: soft lockup - CPU#7 stuck for 67s! [khugepaged] >> >> These messages started appearing today around 7 AM, which is when >> users started reporting the slowdown. They are still occurring >> periodically and the system is still slow. Are these messages caused >> by the slowdown or are they the reason for it? Are they useful in >> tracking down the problem? > > They are what is causing it to appear to run slow. > > The soft lockup is when a CPU is spending a lot of time in kernel mode. > The cause can be a number of things, including overloading or a bug in > the kernel - or sometimes a hardware issue. > > Are you seeing any other possibly hardware related errors in the logs? > > Do you have the 'sensors' package installed and configured - is > everything OK? (An overclocked CPU or a low voltage/bad PSU can cause > this sort of thing.) Sorry for the delay in responding, but that system was down until today for other reasons. Indeed it was a bad power supply that was making it run slow. Never would have guessed that. Thanks so much for the suggestion. Had it replaced and it's running fine now.