Message-ID: <19990316203348.A25705@physik.fu-berlin.de>
Date: Tue, 16 Mar 1999 20:33:48 +0100
From: Axel Thimm <Axel DOT Thimm AT physik DOT fu-berlin DOT de>
To: pgcc AT delorie DOT com
Subject: Benchmarks for floating point operations
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Reply-To: pgcc AT delorie DOT com

We are currently trying to see what we can drain maximally from PII for a
certain flop intensive application (QCD). Until now folks were using gcc 2.8.1
with -O2 -fomit-frame-pointer. I thought I might surprise them with egcs or
pgcc, but the perfomance dropped from 80 to 50 Mflop/s (?)

[This was pgcc 1.1, as I cannot compile any newer snapshot/CVS, see related
mail in this list]

Now I know of gcc to egcs regression, but I thought that pgcc was atop of both
of them. I tried all kind of flags, but I couldn't get the old performance
back.

Is this a known fact? Have others made similar experiences? The program is
memory intensive (small ratio of computations per memory accesses) and perhaps
this is what makes the difference.

Regards, Axel.
-- 
Axel DOT Thimm AT physik DOT fu-berlin DOT de Axel DOT Thimm AT ifh DOT de