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LTO: Speedup.
- From: Toon Moene <toon at moene dot org>
- To: gcc mailing list <gcc at gcc dot gnu dot org>
- Date: Tue, 06 Oct 2009 22:10:19 +0200
- Subject: LTO: Speedup.
L.S.,
On our weather forecasting code (compiled with -O3 -flto and linked with
-O3 -flto -fwhole-program) I get a speedup of 65 seconds per time step
in the model integration vs. 75 seconds with -O3 alone.
That is a 10/75 ~ 13 % improvement.
This compares favorably to an experiment I did back in '92:
Compiling all forecast Fortran code with f2c to make it C code, combine
all the C files in one file in the right order, and slap "static inline"
on all functions. then compiling the resulting file with -O3.
That gave me 10 % at that time.
--
Toon Moene - e-mail: toon@moene.org - phone: +31 346 214290
Saturnushof 14, 3738 XG Maartensdijk, The Netherlands
At home: http://moene.org/~toon/
Progress of GNU Fortran: http://gcc.gnu.org/gcc-4.5/changes.html