kern.smp.topology

[Ivan Klymenko]

Hello! People.

Who can explain the purpose of sysctl variable kern.smp.topology?
What does it affect?

It may take such values:
1 -Dual core with no sharing.
2 -No topology, all cpus are equal.
3 -Dual core with shared L2.
4 -quad core, shared l3 among each package, private l2.
5 -quad core, 2 dualcore parts on each package share l2.
6 -Single-core 2xHTT
7 -quad core with a shared l3, 8 threads sharing L2.
default-Default, ask the system what it wants.

Does it make sense to set its value manually, if I know that my CPU Core2Duo?
How to do this, select a value?

I not found this explanation in any of the official guides ...

Thanks!
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[Ivan Klymenko]

В Wed, 10 Nov 2010 12:20:45 +0100
Ivan Voras <ivo...@freebsd.org> пишет:

> On 11/10/10 11:56, Ivan Klymenko wrote:
> > Hello! People.
> >
> > Who can explain the purpose of sysctl variable kern.smp.topology?
> > What does it affect?
> >
> > It may take such values:
> > 1 -Dual core with no sharing.
> > 2 -No topology, all cpus are equal.
> > 3 -Dual core with shared L2.
> > 4 -quad core, shared l3 among each package, private l2.
> > 5 -quad core, 2 dualcore parts on each package share l2.
> > 6 -Single-core 2xHTT
> > 7 -quad core with a shared l3, 8 threads sharing L2.
> > default-Default, ask the system what it wants.
> >
> > Does it make sense to set its value manually, if I know that my CPU
> > Core2Duo? How to do this, select a value?
> >
> > I not found this explanation in any of the official guides ...
>

> Short answer is: you should not have to touch it, ever.
>
> Long answer: it's used mostly for testing ULE and debugging
> topology-related problems. It's even less relevant in recent kernels
> (9, 8-stable) where a better topology parser has been committed.
>
Thank you! I understood. :)