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On Monday 22 November 2004 08:47, Matthew Groote-Kirsch wrote: |
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> I settled on: |
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> |
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> CFLAGS="-O2 -frename-registers -ftracer -funroll-loops |
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> -fomit-frame-pointer -pipe -march=athlon" |
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> |
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> Looking around on the forums a bit, it seemed like -O2 is recommended |
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> over -O3. |
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|
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Aditionally there have been times when -O2 has been shown to be faster |
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than -O3. Similarly, the -funroll-loops might actually create slower code |
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due to more cache misses. Modern processors are complex systems where |
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nondeterministic parts like the cache can have a significant impact on |
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performance. The only real way to determine what is fastest would be to |
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run real-world (not simple loops) tests (with timing) for each option |
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combination. |
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|
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Paul |
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|
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-- |
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Paul de Vrieze |
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Gentoo Developer |
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Mail: pauldv@g.o |
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Homepage: http://www.devrieze.net |
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