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Re: Estimated SPEC2000 results for gcc+alpha


Brad Lucier wrote:

> mgrid and apsi are embarrassingly (sp?) bad and swim is not so great 
> either.

I've seen the loop that comprises 2/3rds of the run time of mgrid in the
old SPECfp95 test.  It doesn't contain any other floating point
operations than add/sub/mul/div, so it's not surprising that adding
-lcpml doesn't help.

apsi is a weather model (actually a dispersion model derived from a
weather model), so - based on my experience as a meteorologist - I
expect it to be dominated by add/sub/mul/div too.

> Perhaps things would be better if I added -funroll-loops.

Anton Ertl recently posted (comp.arch) results of SPEC95 on Alpha with
and without -funroll-loops - it didn't make a dent; probably because all
the relevant loops are too large to be unrolled by GCC.

Hope this helps,

--
Toon Moene, KNMI, PO Box 201, 3730 AE De Bilt, The Netherlands.
Tel. +31302206443, Fax +31302210407,  e-mail moene@knmi.nl
URL: http://www.knmi.nl/hirlam

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