Starting with (not yet released) OpenBSD 6.4, sysctl KERN_CPTIME2 will
return ENODEV for offline CPUs.
SMT siblings are reported as offline when hw.smt is disabled, which is
the default since one of the later Spectre variants. So this might
affect a few systems.
For more details see:
https://cvsweb.openbsd.org/src/sys/kern/kern_sysctl.c#rev1.348
Signed-off-by: Ralf Horstmann <ralf+github@ackstorm.de>
Ben Ye