Messages in this thread | | | Date | Wed, 13 Aug 2008 19:39:40 +0200 | From | Ingo Molnar <> | Subject | Re: 2.6.27rc1 cannot boot more than 8CPUs |
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* Jeff Chua <jeff.chua.linux@gmail.com> wrote:
> On Thu, Aug 14, 2008 at 1:10 AM, Jeff Chua <jeff.chua.linux@gmail.com> wrote: > > On Wed, Aug 13, 2008 at 10:16 PM, Ingo Molnar <mingo@elte.hu> wrote: > > > >> btw., could you please check that v2.6.27-rc3 (or later) kernels boot > >> fine (with about 8 cpus) even if you have genericarch/bigsmp disabled, > >> and do not silently hang as it happened on your box before? > > > > With 16 CPUs, it still hangs, but now the console is showing the > > errors as intended. > > ... but it is supposed to hang? > > I tried with just CONFIG_NR_CPUS=8 and this time it booted, but stange > thing is I only see 2 CPUs! To be more precise, it's without both > CONFIG_X86_GENERICARCH and CONFIG_X86_BIGSMP. > > And when I tried to enable the CPUs, it complained about: > > # cat cpu6/online > 0 > # echo 1 > cpu6/online > More than 8 CPUs detected - skipping them. > Use CONFIG_X86_GENERICARCH and CONFIG_X86_BIGSMP. > -bash: echo: write error: Input/output error > > Prior to the patch, the system booted with all 8 CPUs. > > Again, if I enable both CONFIG_X86_GENERICARCH and CONFIG_X86_BIGSMP, > I get all 16 CPUs.
Yinghai, could the APIC ID enumeration be nonsequential and we skip CPUs starting at the third one already? I think we should accept all CPUs that are within our support range.
Ingo
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