detecting hyperthreading

[Pokala, Ravi]

Hi folks,

There used to be a sysctl, "machdep.hyperthreading_allowed", which
indicated whether or not the kernel was using hyperthreaded cores. It
looks like it was removed sometime between 8 and 9, for perfectly good
reasons (https://svnweb.freebsd.org/base?view=revision&revision=222853).

That said, is there currently a way to tell at runtime from userland if
hyperthreading is enabled or not?

Thanks,

Ravi