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On 10/04/2010 23:06, luis jure wrote: |
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> |
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> hello list, |
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> |
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> after many years without a hardware upgrade, i'll be receiving my new |
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> computer next week: intel i7 920 cpu, 6 GB ram, asus p6t mobo. |
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> |
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> i'm pretty excited, i imagine that at first i'll be shocked at the |
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> difference with the ancient machine i'm using now. |
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> |
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> now my question: searching a bit for the best compilation flags for |
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> this processor, i found this at gentoo-wiki: |
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> |
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> CHOST="x86_64-pc-linux-gnu" |
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> CFLAGS="-march=core2 -msse4 -mcx16 -msahf -O2 -pipe" |
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> CXXFLAGS="${CFLAGS}" |
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> (http://en.gentoo-wiki.com/wiki/Safe_Cflags/Intel) |
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> |
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> on the other hand, a thread at http://forums.gentoo.org says that the |
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> wiki page is outdated, and that -march=native should do the job without |
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> any further tweaks like -msse4 etc. |
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That is correct; -march=native will indeed do the job. The CFLAGS |
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example you cite is clearly an interpretation of the flags that the |
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native target would result in anyway. |
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With respect to my Intel Xeon E3113, -march=native appears to equate to: |
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-march=core2 -mtune=core2 -msahf -msse4.1 --param l1-cache-size=32 |
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--param l1-cache-line-size=64 |
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In short, use "native" and let the compiler take care of the details. |
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Cheers, |
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--Kerin |
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