On Tuesday 10 October 2006 14:55, JoaoBR wrote:
> On Tuesday 10 October 2006 15:11, Brooks Davis wrote:
> > > My dmesg does not have the line about "Hyperthreading: 2 logical CPUs",
> > > though. But I had been pretty sure the Athlon64 chips didn't have any
> > > hyperthreading support. Why is the HTT there?
> HTT is NOT hyperthreading, HT is and HT does not exist on AMD64
Err, no. The HTT there stands for HyperThreading Technology. I should
know as I added it. :) What it really means is that you can check one
of the registers returned by cpuid 1 to see how many logical CPUs the
current physical CPU package contains. Originally this was only used
for hyperthreads, but it was reused for multi-core as well, so if you
have a dual-core chip with 2 hyperthreads in each core, it reports 4
logical CPUs. If you have 2 cores, it reports 2 logical CPUs. If
you have 1 core with 2 hyperthreads, it reports 2 logical CPUs.