Core Duo SMP Support issue

[Nils Kassube]

Sam Currie wrote:
> I have now upgraded to 2.6.24-18-generic and I'm still having no luck
> getting my second core online.
>
> Can anyone shed any light on this problem please?
>
> 2008/6/3 Sam Currie <sam.currie at gmail.com>:
> > My problem is that I have noticed by Ubuntu 8.04 install is only
> > using one core of my T5500 1.6 GHz CPU.  My machine is a Sony
> > VGN-SZ32GP. After some hunting I found the following interesting
> > message from dmesg, "SMP alternatives: switching to UP code".

That's not very exciting. I see that message as well on my Core 2 Duo 
machine where both cores are in use. However, there is another message a 
few lines below the one you mentioned: "SMP alternatives: switching to 
SMP code". Do you see that message as well?

> > A 'uname -a' spits out:
> > Linux sony-lappy 2.6.24-17-generic #1 SMP Thu May 1 14:31:33 UTC 2008
> > i686 GNU/Linux

OK, same kernel here, -17 or -18 makes no difference for me.

> > A 'cat /proc/cpuinfo' spits out:
> > siblings        : 1
> > core id         : 0
> > cpu cores       : 1

For some reason the kernel only finds one core on your machine. On my 
machine I see the listing twice, i.e. for every core there is a listing 
similar to yours, but the major difference is:

siblings        : 2
core id         : 0
cpu cores       : 2

siblings        : 2
core id         : 1
cpu cores       : 2

While I can't tell you the reason why you only see one core, I can tell 
you that you are using a kernel that works for a dual core machine.


Nils