Message-Id: <34E43E6D.492A663D@informatik.uni-tuebingen.de>
Date: Fri, 13 Feb 1998 13:37:02 +0100
From: Stefan Huelbrock <huelbroc AT informatik DOT uni-tuebingen DOT de>
Organization: Institute for Computer Architecture, University of Tuebingen
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To: beastium-list AT Desk DOT nl
Subject: -mpentiumpro slows things down (even on PentiumPro)
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Sender: Marc Lehmann <pcg AT goof DOT com>
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Hello out there
I'm new at this list and my question isn't in the FAQ, so I'm sorry if
it _is_
a FAQ.
I've compiled and installed pgcc 1.01 on my linuxbox.
Optimization for pentium seems to work like a charm:
gzip compiled with gcc 2.7.2.1 -O6 needs 69.86s
gzip compiled with pgcc 1.01 -O6 needs just 65.4s
which is a win of about 6.7percent.
Ok... test on a PentiumPro-box gives for
gcc 2.7.2.1 -O6 41.8s
pgcc 1.01 -O6 42.24s.
Allright, the binarie is compiled for a pentium, so theres a little
loss to expect.

Now trying -mpentiumpro...
now it takes
pgcc 1.01 -O6 -mpentiumpro 72.41s on a pentium, and
pgcc 1.01 -O6 -mpentiumpro 42.13s on a pentiumpro.

This is considerable slower than the output of gcc 2.7.2.1.
Is this still under development or is the compiler just thought for
working well on a pentium with a slower pentiumpro-code as a
tradeoff, or do I just miss anything? Maybee my installation isn't
flawless? Do you experience the same?

BTW tests with bzip2 shows the same results.

Thanks in advance
Stefan


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Stefan Huelbrock. Voice (+49/0) 7071-29-77176
Uni Tuebingen, WSI, Computer Architecture, Koestlinstr. 6
D-72074 Tuebingen    eMail: huelbroc AT informatik DOT uni-tuebingen DOT de
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