Re: how to detect the number of processors ?

[Jerome BENOIT <jgmbenoit@mailsnare.net>]

Hi,

thanks for your answers.

strawks wrote:
> Hello,
>
> > sorry, I forgot to tell that `/proc/cpuinfo'
> > shows up _two_ processors (when the kernel is a SMP one).
> >
> > Furthermore,
> > the concerned black box is a very old one:
> > before september 2003 (kernel 2.4.22).
> >
> > According to `/proc/cpuinfo', there are two
> >
> >  Intel(R) Pentium(R) 4 CPU 3.20GHz (model name)
> >
> > with `stepping' 9.
>
> Maybe it's not present in the 2.4 kernels, but there is now a physical
> id line in /proc/cpuinfo. If your 2 processors have the same physical
> id, it's a dual core or a P4 HT (Hyperthreading).
> I think it's probably a P4 HT. To be sure check the presence of the flag
> "ht".
>
> > As I may need a lot of CPU time, I would like to know
> > if it makes sense to install a SMP kernel on this black
> > box (and its shelf brothers):
> > who must I try ?
>
> If this is a P4 HT, take a look at this page :
> http://www.ibm.com/developerworks/linux/library/l-htl/


Indeed I have a P4 HT :
must I build a SMP kernel as suggested by Knoppix ?


> If it's a dual core yes you should install a SMP kernel to take
> advantage of the 2 cores.
>
>
> > Can a SMP kernel be confused by a one CPU computer
> > (and announce two CPU instead of one).
>
> I don't think the kernel could show 2 CPUs if there is only one, as each
> CPU are initialized one after another.

Thanks in advance,
Jerome

--
Jerome BENOIT
jgmbenoit_at_mailsnare_dot_net