Constant load of 1 on a recent 12-STABLE

[Ian Lepore]

On Wed, 2020-06-03 at 22:29 +0200, Gordon Bergling via freebsd-hackers wrote:
> [...]
> 
> The only key performance indicator that is relatively high IMHO, for a 
> non-busy system, are the context switches, that vmstat has reported.
> 
> -------------------------------------------------------------------------------
> procs  memory       page                    disks     faults         cpu
> r b w  avm   fre   flt  re  pi  po    fr   sr da0 da1   in    sy    cs us sy id
> 0 0 0 514G  444M  7877   2   7   0  9595  171   0   0    0  4347 43322 17  2 81
> 0 0 0 514G  444M     1   0   0   0     0   44   0   0    0   121 40876  0  0 100
> 0 0 0 514G  444M     0   0   0   0     0   40   0   0    0   133 42520  0  0 100
> 0 0 0 514G  444M     0   0   0   0     0   40   0   0    0   120 43830  0  0 100
> 0 0 0 514G  444M     0   0   0   0     0   40   0   0    0   132 42917  0  0 100
> --------------------------------------------------------------------------------
> 
> Any other ideas what could generate that load?
> 
> Best regards,
> 
> 

Interrupts/second consistently zero is the strange part of that vmstat
output.  That makes me think the problem has something to do with
timekeeping and is a problem with the statistics used by top rather
than having some "stuck process" actually consuming time.

Are there any other signs of timekeeping trouble on the machine, like
ntpd repeatedly stepping the clock?  What's the output for

  sysctl kern.timecounter
  sysctl kern.eventtimer

-- Ian