Re: P4 optimized Debian GNU/Linux?

[Thiemo Seufer <ica2_ts@csv.ica.uni-stuttgart.de>]

Nano Nano wrote:
[snip]
> > When I run the program with no optimization -O0, I got some numbers that 
> > looked about the same for both machines. Then I compiled with 
> > -march=pentium-4 and -march=athlon-xp and -O6, and surprise, surprise, 
> > the P4 had a speed *decrease*!! It slowed down from something like 23 
> 
> I did enough performance work at Microsoft to know that your test is 
> meaningless.  Just because you know X at level Y doesn't imply a thing 
> about your knowledge at level 10Y, good or bad.  The program might get 
> slower, or faster, or crash.
> 
> Some people call this "nonlinear."  A perf expert described it to me as 
> more accurately: stochastic.
> 
> So you can draw no conclusions whatsoever from your test.

The conclusion is: Switching on all the optimizations is no silver bullet.


Thiemo