Re: 2.6.27rc1 cannot boot more than 8CPUs

Ingo Molnar
2008-08-11T20:00:15Z

* Jeff Chua <jeff.chua.linux@gmail.com> wrote:

> On Wed, Aug 6, 2008 at 2:42 PM, Jeff Chua <jeff.chua.linux@gmail.com> wrote:
> > On Wed, Aug 6, 2008 at 2:01 PM, Linus Torvalds
> > <torvalds@linux-foundation.org> wrote:
> >> One trivial thing to try would be to just bisect it. I assume 2.6.26 is
> > Bisecting now.
>
> Thanks to all the great helpful suggestions from everyone, and this
> turns out that I just need to enable the following switches, so I
> didn't bisect further, and since it's first machine that I've tried
> with more than 8 CPUs so I wasn't sure whether 2.6.16 has the same
> problem, but if you wish, I could give 2.6.16 a try.
>
> > CONFIG_X86_GENERICARCH=y
> > CONFIG_X86_BIGSMP=y
>
> Thank you all for the great linux kernel!

i still consider a silent boot hang a bug we need to fix.

bigsmp might be required to have all cpus available on your box, but the
kernel is still supposed to transparently fall back to less CPUs (and
print a warning) if it cannot do that.

Ingo