Re: HT vs. dual-core

[Jason Baron <jbaron redhat com>]

On Tue, 24 Jan 2006, Chris Adams wrote:

> Once upon a time, Jason Baron <jbaron redhat com> said:
> > On Tue, 24 Jan 2006, Chris Adams wrote:
> > > I just got a new server with 2 physical Intel Xeon CPUs, and I see 4
> > > logical CPUs.  How do I tell the difference between hyperthreading (I
> > > see the "ht" flag) and dual-core?  Is there a way under Linux?
> > 
> > If you look at /proc/cpuinfo there are two fields of relevance: "siblings" 
> > and "cpu cores".
> > 
> > "siblings" = (ht per cpu package) * (# of cores per cpu package)
> > "cpu cores" = (# of cores per cpu package)
> > 
> > Thus:
> > 
> > ht per cpu package = "siblings" / "cpu cores"
> 
> So when I see 4 entries in /proc/cpuinfo, all with "siblings : 2" and
> "cpu cores : 1", that means I have two single-core hyperthreading CPUs?
> 

yup.