Re: Is sysfs the right place to get cache and CPU topology info?

Andrew Morton
2008-07-02T16:47:25Z

On Wed, 2 Jul 2008 21:46:47 +1000 Paul Mackerras <paulus@samba.org> wrote:

> > If they're talking about using the existing ones then sure, those are
> > cast in stone as far as I'm concerned.
> >
> > But they do need to be a _bit_ defensive. If they see a file which has
> > multiple name:value fields (shouldn't happen) then don't fail if new
> > tuples turn up later on. Don't expect them to always be in the same
> > order. Don't fail if new files later turn up in a sysfs directory. If
> > a file has (a stupid) format like /proc/self/stat then be prepared for
> > new columns to appear later on, etc.
> >
> > But if basic and obvious steps like that are taken in the library, and
> > later kernel changes cause that library to break, we get to fix the
> > kernel to unbreak their library.
>
> I assume they can rely on finding the stuff they need under
> /sys/devices/system/cpu. Or do they need to traverse the whole of
> /sys, and if so, how would they know which directories they should be
> looking in?

/sys/devices/system/cpu sounds good to me. Everyone's mounting it at
/sys.