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

[Tom Crick]

Not sure if this is exactly what you are looking for, but I've
previously looked at a piece of software called ACOVEA (Analysis of
Compiler Options via Evolutionary Algorithm) by Scott Robert Ladd
(http://www.coyotegulch.com/products/acovea/).

This attempts to find the 'optimal' set of compiler flags for GCC
(recently updated for GCC 4.0) using genetic algorithms. This seems to
be particularly relevant for GCC, with the abundance of existing flags
and options.

Cheers,

Tom

-- 
Tom Crick
Mathematical Logic & Symbolic Computation Group
Department of Computer Science
University of Bath
tc at cs.bath.ac.uk
http://www.cs.bath.ac.uk/~tc

On Tue, 2005-05-10 at 20:00, beowulf-request at beowulf.org wrote:
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Tue, 10 May 2005 14:39:54 -0400 (EDT)
> From: Steve Cousins <cousins at limpet.umeoce.maine.edu>
> Subject: [Beowulf] Table of best compiler flags for different CPUs?
> To: beowulf at beowulf.org
> Message-ID:
> 	<Pine.LNX.4.10.10505101415590.14786-100000 at limpet.umeoce.maine.edu>
> Content-Type: TEXT/PLAIN; charset=US-ASCII
> 
> 
> 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.
> 
> 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