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On Dienstag 26 Mai 2009, Stroller wrote: |
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> Hi there, |
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> |
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> I'm always rather reluctant to enable any of these, being unsure |
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> whether my ageing PentiumPro or Pentium 4 CPUs support such features |
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> as 3DNow! (originally an AMD technology) or the advanced SSSSSSSSSE3. |
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> |
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> According to this page <http://en.gentoo-wiki.com/wiki/MPlayer>, |
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> however: |
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> |
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> You can greatly improve MPlayer's performances (in my experience, by |
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> up to +40%!) by recompiling it with appropriate CPU-related USE |
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> flags. |
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> |
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> Moreover: |
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> |
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> Note: The mplayer build system will automatically detect your CPU |
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> settings if you allow it. Therefore, the safest thing to do is |
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> enable |
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> all of the optimization USE flags and let the script detect them. If |
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> you disable the use flags, then it will forcibly disable support for |
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> that optimization, and possibly break your build. In other words, |
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> add |
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> mmx mmxext sse sse2 ssse3 3dnow 3dnowext to your USE flags for this |
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> ebuild, and if your box supports it, it will work automatically. |
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> |
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> w00t! |
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> |
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> Should I enable all these USE flags globally? Will other packages also |
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> fallback safely as mplayer does? |
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> |
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> Or should I add all these flags only to /etc/portage/package.use, |
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> allowing mplayer to make full use of the hardware USEs it supports, |
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> but limiting other apps to only those I'm really really confident |
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> about (i.e. "mmx" & that's about it). |
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> |
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> Thanks in advance for all suggestions, |
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> |
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> Stroller. |
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|
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you can enable them globaly. |
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|
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If a package would build using say 3dnow without the cpu supporting it it will |
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crash with an instruction error. So either it works always or never. |
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|
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Just look at /proc/cpuinfo you find everything you need to know there. It |
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isn't hard. In fact, it is really ,really simple. |