From: Wu Y. <ad...@ne...> - 2002-07-25 02:00:45
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My tests seemed to show that the GCC -m options do not always accelerate the code on Celeron and even Pentium III machines. In some tests, the default i386 architecture was the fastest on my Celeron 550MHz box. The -mpentiumpro option did have effect on Pentium 4 machines, but often not otherwise. My tests were done in GCC 2.95.3. GCC 3.x might be different, but I have not tested yet. Best regards, Wu Yongwei --- Original Message from Danny Smith --- > GCC's stdlib static libraries optimized for differing architectures. > > Scenario: > I build GCC with -march=i686 and install. > I build FOO with -march=i386 and distribute. > FOO fails to run on lesser than march=i686 due to the static GCC > libraries that were optimized for march=i686. My Question: Have you quantified the benefit of -march-i686.on standard runtime libraries (libgcc.a, libstdc++.a and other languages). Is it really worth all the bother? > > Question: > What might other methods be? Compromise. Leave the instruction set alone. Tweak the scheduling with -mcpu if you see any benefit. Danny > > Earnie. |