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On Thursday 03 November 2005 09:47, Duncan wrote: |
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> So... certainly for kernel and probably for glibc stuff (tho I believe |
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> Gentoo kills -Os on glibc compiles unless you hack out that portion of the |
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> ebuild, in your own overlay or whatever), -Os is likely to be the best |
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> choice. For most of userland, -Os may be best, but to a smaller degree, |
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> and performance should be similar with -O2, trading size for medium speed |
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> optimizations in what amounts to a wash. The exceptions would likely be |
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> media encoders and the like, where the working set is large and in a data |
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> streaming environment, and -O3 may make sense. In the general case, |
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> however, -O3 likely does NOT make sense, because it's almost always so |
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> expensive in size that the gains in speed over -O2 are far outweighed. |
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AFAIR and so on. |
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Os is 'forbidden' for glibc, because there were some gcc bugs, that |
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miscompiled glibc with Os. |
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But with gentoo 1.2/1.4, I went for some time with Os in CFLAGS - and my |
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system was not faster than with O2. But it was a little faster with Os or O2 |
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than O3 ;) |
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-- |
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