[ale] Detecting multiple CPUs

Michael D. Hirsch mhirsch at nubridges.com
Mon Sep 8 14:04:54 EDT 2003


On Monday 08 September 2003 11:16 am, Chris Ricker wrote:
> On Mon, 8 Sep 2003, Jonathan Glass wrote:
> > I'm guessing you can only tell by seeing if you have 2 or 4 CPUs
> > showing up in /proc/cpuinfo.  My dual-Xeon 2 GHz boxes
> > w/Hyperthreading (running RH 8 2.4.20-20.8smp) shows the following:
> >
<snip>

> > flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
> > mca cmov
> > pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm
>
> the ht here in flags tells you this is hyperthreaded.

AHA!  I see the ht flag in my /proc/cpuinfo, so that tells me that I 
probably only have 1 CPU which is hyperthreaded.  If I didn't have an SMP 
kernel I wouldn't se more than one CPU under any circumstances. Thanks!

Anyone know when hyperthreading came to the 2.4.x kernel?  This system is 
still running 2.4.18-smp from redhat (RH 7.2).

--Michael



More information about the Ale mailing list