Re: HZ, preferably as small as possible

Linus Torvalds
2002-07-15T18:51:51Z

On Mon, 15 Jul 2002, Albert D. Cahalan wrote:
>
> It's not a different value in libproc. There's autodetection.
> I can't just support "the majority of ARM", and people keep
> giving me shit about HZ supposedly being a per-arch constant.
> (not that there's a sane way to get a per-arch constant from
> user code anyway)

But that's just _wrong_.

There _is_ a sane way to get the per-arch constant, and there has been for
a long long time.

The kernel exports it with the AT_CLKTCK ELF auxiliary note to every ELF
binary ever loaded, and I think glibc in turn exports that value through
the regular sysconf(_SC_CLK_TCK) thing. (Yeah, I disagree with some of the
glibc sysconf implementation, but it sure should be there, and it's
documented).

If that doesn't work, then it's a glibc bug (well, in theory there could
be a kernel bug too, but since it's a one-liner in the kernel I really
doubt it).

Linus