Re: Impossible

["B. James Phillippe" <bryan terran org>]

On Tue, 8 Sep 1998, Mark Dohojda wrote:

> He run C program in NT and in Linux (on the same box), and NT proved to
> be 30% faster.  Now I don't know much about the code, however I know
> that he used the same sources on both of the operating systems.  Also
> the source (to the best of my knowledge) was in no way optimized for NT.
...
> My question is, how can NT beat Linux????? Is that possible? And what to
> do, to make sure that Linux is not going to look bad.

It's impossible to know what's happening without knowing what this program
does.  One theory: I've heard that the Linux Alpha math libraries are
really slow and inefficient.  If the program uses floating point a lot,
that might be the problem.  Another very likely candidate is the compiler:
I've also heard Microsoft's Alpha compiler is actually Digital's handiwork.
The compiler that comes with RedHat is not really the best available.  You
could try getting egcs-1.1 release from http://egcs.cygnus.com and
compiling it with the Haifa scheduler, then rebuilding your code with
something like -O3 -ffast-math.  Let us know what the results are.

cheers,
-bp
--
B. James Phillippe <bryan@terran.org>
Linux Software Engineer, WGTI.
http://earth.terran.org/~bryan