CPU: Intel i9-7900x 10 cores. Distribution: Ubuntu 16.04.3 On boot, the processes migration/1 and migration/2 indicate that they have used a huge amount of CPU time (the times are meaningless, typically between 2-100 hours, so it seems unlikely that migration is actually using this amount of CPU time). The other migration processes are always zero. This occurs at some point during the boot process before I can log into the system. ps -ealdf | grep migration 1 S root 9 2 0 -40 - - 0 - 19:20 ? 00:00:00 [migration/0] 1 S root 12 2 99 -40 - - 0 - 19:20 ? 02:38:00 [migration/1] 1 S root 18 2 99 -40 - - 0 - 19:20 ? 02:38:00 [migration/2] 1 S root 23 2 0 -40 - - 0 - 19:20 ? 00:00:00 [migration/3] 1 S root 28 2 0 -40 - - 0 - 19:20 ? 00:00:00 [migration/4] After logging in, the migration processes do not consume a significant amount of CPU time, no matter what is running. I checked _SC_CLK_TCK after logging in thinking this might be screwed up: sysconf(_SC_CLK_TCK) = 100 Interestingly enough, if I power off the system, migration/1 and migration/2 show reasonable results after the boot process is finished: 1 S root 9 2 0 -40 - - 0 - 16:42 ? 00:00:00 [migration/0] 1 S root 12 2 0 -40 - - 0 - 16:42 ? 00:00:01 [migration/1] 1 S root 18 2 0 -40 - - 0 - 16:42 ? 00:00:01 [migration/2] 1 S root 23 2 0 -40 - - 0 - 16:42 ? 00:00:00 [migration/3] 1 S root 28 2 0 -40 - - 0 - 16:42 ? 00:00:00 [migration/4] (truncated...) Warm booting the system results in the original problem. Note that this doesn't seem to cause any problems with the system (except messing up some of the CPU usage stats in webmin).