[CentOS] Re: Hot swap CPU -- "build" is not a good CPU benchmark

[Bryan J. Smith <b.j.smith@ieee.org>]

From: Peter Arremann <loony at loonybin.org>
> It is a valid benchmark though :-) compile speed is a actually a
> good measure for any integer app that is small enough to run in
> large cache... Image processing, oil companies for their simulations,
> cad... they all act very similar to compile benchmark - if a compile
> is twice as fast, a software image rendering is usually twice as fast
> too :-)

Now hold on.  Did I just here you state that the ALU is used for CAD,
and most scientific and engineering applications?

Now I'll grant you that _some_ image processing _can_ be 32/64-bit
integer transforms.  But most high-quality, 64-bit precise transforms
use the FPU.  Not even Intel's SSE (on the P3/P4) is good when you
need such precision.

In fact, I don't know how many times I've caught errors because
someone threw the "-O3" switch on "-march=p4".  You do _not_
want to use SSE for scientific computing -- it's for when you
want performance in exchange for loss of precision (let alone
accuracy).

> If you run databases or so, then yes, your comment is valid. 

Thank you.

> Fair enough :-) 

And people say *I* go off on tangents.

No offense, you were already in 2 posts before I even responded.
If you look at other threads, I'm typically responding "OT" after
2-3 people have done so, and I largely see an inaccuracy, or I
see a correction very much necessary.

[ My posts on that thread _prior_ had just been to inform people
that yes, there _were_ Xeon and Itanium systems with hot-swap
capability. ]

That's all I was trying to do in this case.  Not "prove you wrong."



--
Bryan J. Smith   mailto:b.j.smith at ieee.org