On 06/11/2009 12:30 PM, Duncan wrote:
Volker Armin Hemmann<volkerar...@googlemail.com> posted
200906110022.26698.volkerar...@googlemail.com, excerpted below, on Thu,
11 Jun 2009 00:22:26 +0200:
On Donnerstag 11 Juni 2009, Greg wrote:
I've been having trouble determining if my processor has
hyper-threading. I'm thinking that it does. I know that it isn't a
dual-core.
If it is a hyper-thread processor, I can't seem to figure out exactly
how to enable the hyper-thread under linux.
no amd supports hyper-threading. They have that flag because they are
compatible - and if they are multicore to 'trick' stupid software that
checks for ht to multi thread but does not multithread on multicore
cpus.
More to the point, AMD CPUs don't /need/ hyper-threading to run
efficiently.
Here's the deal on hyper-threading.
It first became popular (and I believe was first introduced, but I may be
mistaken on that) with the Intel "Netburst" architecture, back in the
last gasps of the clock-rate-is-everything era when Intel was doing
everything they could to write those last few hundred MHz out of their
CPUs, even at the expense of such deep pipelines that it actually hurt
performance in many cases. (Plus it ran way hot, and sucked up power at
such a rate that people were doing projections indicating that at the
rate things were going, in a few years each CPU was going to need its own
Nuclear reactor power supply... and the cooling to go along with it!)
Happily Intel has moved beyond that stage now, and the core-2s and
beyond, and moving to true dual-core and beyond, they once again began
competing extremely favorably against AMD, but netburst was the last gasp
of the old "ever higher clocks" process, and it simply didn't compete
well at all.
Intel re-introduced HyperThreading with Core i7 a while back.
