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Am 11.06.2011 17:25, schrieb Jarry: |
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> Hi, |
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> how should I change/set CFLAGS/CXXFLAGS/CHOST if I want to have |
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> system which can be easily migrated between AMD64 and Intel/Core |
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> without recompilation? I have a few virtual servers which I can |
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> not move from one arch to the other, as they have hw-specific |
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> CFLAGS (different host-server hardware, both AMD64 and EM64T): |
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> |
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> I have systems with Athlon64/X2 and Core2Quad, with settings: |
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> CFLAGS="-march=athlon64 -O2 -pipe" |
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> CFLAGS="-march=core2 -O2 -pipe" |
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> CHOST is always "x86_64-pc-linux-gnu". |
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> |
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> I'm not sure "-mtune=generic" is the right solution, because |
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> it would generate code for IA32/AMD64/EM64T (if I understand |
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> gcc manual correctly, for both 32bit as well as 64bit HW). |
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> |
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> What I'm looking for are some generic 64bit settings only for |
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> AMD64/EM64T (not 32bit/IA32) similar as for distros with binary |
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> distributions (i.e. I can download Ubuntu either 32bit or 64bit |
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> version, no other hardware-specific difference). I know with |
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> "universal" 64bit binaries I'm going to loose some pefrormance, |
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> but for me flexibility with migration would overweight this |
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> disadvantage... |
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> |
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> Jarry |
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> |
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|
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Unless you specify -m32, your x86_64 gcc will create generic x86_64 |
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code. That means it will use the common AMD64/EM64T instruction set |
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which also includes SSE2 instructions. |
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|
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Regards, |
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Florian Philipp |
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