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On Mon, Nov 23, 2020 at 9:10 AM Walter Dnes <waltdnes@××××××××.org> wrote: |
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> |
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> Ouch! Are the CPUs exactly identical? If not, then you may get the |
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> "Illegal instruction" error. This is a "feature" of Gentoo, which is |
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> often user-optimized for a specific CPU. |
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This "feature" has nothing to do with Gentoo, but just with the fact |
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that users can set their CFLAGS to whatever you wish. If you set a |
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conservative -march and then set a more aggressive -mtune then your |
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binaries will run anywhere. That is how most distros do it. |
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The default CFLAGS in make.conf are "-O2 -pipe". If you stick to |
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those defaults your binaries will run anywhere. |
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There is nothing wrong with using -march, but you definitely need to |
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keep in mind that if you ever change CPUs then you're going to need to |
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rebuild everything. |
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You could just rebuild @system with generic CFLAGS and then rebuild |
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everything with -march=native or whatever you prefer once your new |
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system is running. Your applications wouldn't run that way, but you |
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could still boot the OS and the toolchain will work. If gcc is broken |
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then you can't rebuild in place. |
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-- |
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Rich |
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