Re: Hyper-Threading Vulnerability

Andi Kleen
2005-05-13T19:16:03Z

On Fri, May 13, 2005 at 02:49:25PM -0400, Scott Robert Ladd wrote:
> Alan Cox wrote:
> > HT for most users is pretty irrelevant, its a neat idea but the
> > benchmarks don't suggest its too big a hit
>
> On real-world applications, I haven't seen HT boost performance by more
> than 15% on a Pentium 4 -- and the usual gain is around 5%, if anything
> at all. HT is a nice idea, but I don't enable it on my systems.

I saw better improvement in some cases. It always depends on the workload.
And on the generation of HT (there are three around). And lots of other
factors.

Even for your workload only it does not seem to me to be very rational
to throw away a 15% speedup with open eyes.

-Andi