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Paul Stear posted on Sat, 05 Feb 2011 15:45:08 +0000 as excerpted: |
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> I am currently using amd64 2 core processor but now have the chance |
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> to use an intel quad 64 processor. |
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> This might be a silly question but is it best to do a compltly new |
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> install? If so which stage do I download from the following list:- |
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> |
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> alpha: iso stages |
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> amd64: iso stages |
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> arm: stages |
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> hppa: stages |
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> ia64: iso stages |
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> ppc/ppc64: iso stages |
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> s390/s390x: stages |
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> sh: stages |
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> sparc: iso stages |
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> x86: iso stages |
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> |
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> Which chost and cflags should I use? |
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Intel em64t (as opposed to the Itanics/Itaniums) is amd64 by another name. |
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So use the amd64 stages if you want 64-bit, or the x86 stages if you want |
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legacy 32-bit. (FWIW, ia64, Intel Arch 64, would be for the Itaniums. |
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Sometimes people get that mixed up, but unless you know you have that |
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hardware, it's pretty safe to assume it's amd64/em64t/x86_64, NOT ia64.) |
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Assuming amd64, whether you /have/ to start from fresh stages or can use |
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your existing install, depends on how similar the hardware extensions are, |
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and whether you used -march or -mtune on your previous install. If you |
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used -mtune, the old install should work as it will have used only |
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instruction ordering for your target hardware, with generic instructions. |
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If you used -march, it will have used targeted instructions as well, and |
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may or may not work. You can try it if you like as going older to newer |
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it's likely to work, but really, starting with a new CPU is a good excuse |
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to start fresh, eliminating any possible cruft left over from the old |
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system, so I'd recommend starting from new stages even if the old ones |
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would work, unless you're lazy and simply want to avoid that extra |
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compiling. |
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If you want to target the new hardware and are using a new enough gcc (I |
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think the stage supplied one is new enough, now), you can simply use |
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-march=native to take advantage of its instructions. If you'd prefer to |
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have the compiled packages be installable on either machine (say if you |
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run FEATURES=buildpkg to get the binpkgs to do so), but tuned for the new |
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one, use -mtune=native on the new one instead, possibly with -march set |
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for the common subset of both instruction sets, tho you'd of course have |
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to set that subset specifically, which means researching what it is. |
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CHOST will normally be the same, x86_64-pc-linux-gnu , unless you're doing |
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something strange or using legacy 32-bit x86 instead of amd64. |
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|
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-- |
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Duncan - List replies preferred. No HTML msgs. |
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"Every nonfree program has a lord, a master -- |
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and if you use the program, he is your master." Richard Stallman |