BLAS-1, AMD, Pentium, gcc

[Hung Jung Lu]

Hi,

I am thinking in migrating some calculation programs
from Windows to Linux, maybe eventually using a
Beowulf cluster. However, I am kind of worried after I
read in the mailing list archive about lack of
CPU-optimized BLAS-1 code in Linux systems. Currently
I run on a Wintel (Windows+Pentium) machine, and I
know it's substantially faster than equivalent AMD
machine, because I use the Intel's BLAS (MKL) library.
(I apologize for any misapprehensions in what
follows... I am only starting to explore in this
arena.)

(1) Does anyone know when gcc will have memory
prefetching features? Any time frame? I can notice
very significant performance improvement on my Wintel
machine, and I think it's due to memory prefetching.

(2) I am a bit confused on the following issue: Intel
does release MKL for Linux. So, does this mean that if
I use Pentium, I still get full benefit of the
CPU-optimized features in BLAS-1, despite of gcc does
not do memory prefetching? How is this possible?

(3) Related to the above: for general linear algebra
operations, is Pentium processor then better than AMD,
since Intel has the machine-optimized BLAS library? I
get contradictory information sometimes... I've seen
somewhere that Pentium-4 compares unfavorably with AMD
chips in calculation speed... Any opinions?

thanks,

Hung Jung Lu

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