[Beowulf] Table of best compiler flags for different CPUs?

Kozin, I (Igor) i.kozin at dl.ac.uk
Tue May 10 13:16:12 PDT 2005

It is generally a good idea to look up what other
published benchmarks used to build their codes.
Two obvious good sources are SPEC and Stream.
http://www.polyhedron.com/ is quite useful too.
But I must admit that the obscure options used
there were seldom useful to me apart from building
the respective codes on respective hw.
> The recent thread comparing Opterons to Xeon/Nocona brought up some
> interesting points about compilers for different CPU's.  Has anyone
> created a table of CPU type vs Compilers, showing what flags 
> to use to get
> the best performance for a given CPU/Compiler pair? 
> I know "best performance" depends on the application but 
> hopefully there
> are some basic flags that will work pretty well with any 
> floating point
> intensive applications (I know, not everyone is doing floating-point
> applications but that is my domain). Of primary concern to me 
> are finite
> element and finite difference models.  The compilers that I am mainly
> interested in are Gnu Fortran, Portland Group Fortran and the Intel
> Fortran compilers, although a more complete table would of 
> more general
> interest I'm sure.
> I have compared a number of CPU's using one of our ocean models and
> recently I compared a Dual 3.0 Ghz Xeon Nocona to a Dual 2.6 
> Ghz Opteron
> using an old version (3.2.4) of the Portland Group compiler using the
> -fast switch. The Opteron was 71% faster.  This is presumably a fairly
> dumb way to test the relative merits of each CPU so (not 
> being a compiler
> sophisticate) I am interested in what combinations of compilers and
> switches will give a better comparison, as well as run our 
> code faster.

serial or parallel?
Please, post a link if published.

> Thanks,
> Steve
> ______________________________________________________________________
>  Steve Cousins, Ocean Modeling Group    Email: cousins at umit.maine.edu
>  Marine Sciences, 208 Libby Hall        http://rocky.umeoce.maine.edu
>  Univ. of Maine, Orono, ME 04469        Phone: (207) 581-4302
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