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BartNL
n00b
Joined: 29 Aug 2004
Posts: 65
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 Posted: Tue Mar 04, 2014 10:46 pm Post subject: Change of CFLAGS |
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My gentoo system is running perfect. I have an intel i5 4570 haswell processor. When i installed gentoo i used the corei7 cflag. Later i read the wiki save cflags wich says to use core-avx2. What should i do? Change the cflag and run emerge -avuDN world?
In my kernel config i selected core2/newer. Is that correct, or do i need a patch? |
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hydrapolic
Tux's lil' helper
Joined: 07 Feb 2008
Posts: 126
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| Posted: Wed Mar 05, 2014 6:58 am Post subject: |
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Or you may use native if you have a recent gcc that supports it:
CFLAGS="-mtune=native -O2 -pipe"
CXXFLAGS="${CFLAGS}" |
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aCOSwt
Bodhisattva
Joined: 19 Oct 2007
Posts: 2537
Location: Hilbert space
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| Posted: Wed Mar 05, 2014 8:07 am Post subject: Re: Change of CFLAGS |
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| BartNL wrote: | | In my kernel config i selected core2/newer. Is that correct, or do i need a patch? |
Yes it is correct.
BTW, you'll notice that starting from 3.13 kernels, you get the ability to select a wider range of families, in particular one dedicated to your processor :
CONFIG_MCOREAVX2:
Select this for AVX2 enabled processors including Haswell.
Enables -march=core-avx2
BTW only efficient with gcc >= 4.7
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