Re: 2.6.27rc1 cannot boot more than 8CPUs

["Yinghai Lu" <yhlu.kernel@gmail.com>]

On Wed, Aug 6, 2008 at 4:09 AM, Jeff Chua <jeff.chua.linux@gmail.com> wrote:
>
> On Wed, Aug 6, 2008 at 5:42 PM, Jeff Chua <jeff.chua.linux@gmail.com> wrote:
>>>>
>>>> CONFIG_X86_GENERICARCH=y
>>>> CONFIG_X86_BIGSMP=y
>>>> 8 more cpu need bigsmp mode.
>
>> Just found it under " Subarchitecture Type (Generic architecture)",
>> and then it shows the CONFIG_X86_BIGSMP option.
>
> It works. Booted with 16CPUs. 32GB RAM.
>
> CPU0 L7345 1.86GHz  0C
> CPU1 L7345 1.86GHz  0C
> CPU2 L7345 1.86GHz  0C
> CPU3 L7345 1.86GHz  0C
> CPU4 L7345 1.86GHz  0C
> CPU5 L7345 1.86GHz  0C
> CPU6 L7345 1.86GHz  0C
> CPU7 L7345 1.86GHz  0C
> CPU8 L7345 1.86GHz  0C
> CPU9 L7345 1.86GHz  0C
> CPU10 L7345 1.86GHz  0C
> CPU11 L7345 1.86GHz  0C
> CPU12 L7345 1.86GHz  0C
> CPU13 L7345 1.86GHz  0C
> CPU14 L7345 1.86GHz  0C
> CPU15 L7345 1.86GHz  0C
>
>
> So, but setting the config not obvious. And should CONFIG_X86_PC be
> considered as well as CONFIG_X86_GENERICARCH?
>
> With CONFIG_X86_PC, I can set CONFIG_SPARSEMEM=y.
>
> With CONFIG_X86_GENERICARCH, CONFIG_SPARSEMEM depends on CONFIG_NUMA.
>
> I'm using the patch below to enable sparsemem instead of flatmem, but don't
> know what impact it has. System booted and running.
>
> It would be nice to automatically default CONFIG_X86_BIGSMP with CPUs > 8.
> But I don't know to do that.
>
>

actually x86_pc is one mode of genericarch..., genericarch already
could detect pc, bigsmp, and numaq, es7000, bigsmp, visew..

hope later we can change mach_default to default. but embed guys may
want to keep it as seperated one.

in the dmesg when booting x86_pc only, we already have warning to let
you set bigsmp if you have 8 more cpus.

YH