Re: /proc/cpuinfo and hyperthreading

From: Richard B. Johnson (
Date: Mon Dec 16 2002 - 09:10:30 EST

On Mon, 16 Dec 2002, Brian Jackson wrote:

> You could always boot once with nosmp and run some benchmarks and then
> reboot (with smp) and run some more benchmarks, and see if there is a
> difference.
> --Brian Jackson
> Scott Robert Ladd writes:
> > Zwane Mwaikambo wrote:
> >> It's ok.
> >
> > I'm not so sure.
> >
> > To get the most benefit from two logical CPUs, don't I need the kernel to
> > operate as a 2-CPU SMP system?
> >
> > Windows XP initializes the system as SMP with two CPUs; when I run an OpenMP
How do you know this? How can I learn what Windows does with
Win/2000/professional? The only way I know I have two CPUs is when the
machine fails to reboot because the file-system has been completely
trashed by the two CPUs banging on it at the same time. The solution has
been to remove one CPU. M$ claims; "Windows will over-power the system
if two CPUs are present...." Direct quote. If you have two logical
CPUs, you can't remove one, therefore, unless M$ has fixed the problem(s)
in XP, you can't use Windows with two logical CPUs, i.e., hyperthreading.

> > application under Windows, it reports two CPUs and a maximum of two threads.
> > Under Linux,
> >

Dick Johnson
Penguin : Linux version 2.4.18 on an i686 machine (797.90 BogoMips).
Why is the government concerned about the lunatic fringe? Think about it.

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This archive was generated by hypermail 2b29 : Mon Dec 23 2002 - 22:00:13 EST