Changing the default 32-bit x86 arch for Fedora 12

Bill Nottingham notting at redhat.com
Mon Jun 15 17:53:13 UTC 2009


Way back when in February [1], FESCo decided that for Fedora 11, i586 would
be the default architecture, and for Fedora 12, it would be some variant of
i686. It's time to follow through on that action item.

I've submitted https://fedoraproject.org/wiki/Features/F12X86Support. It
defines the default arch as i686 + SSE2.

Why?

- Faster and more consistent FP math by using SSE2 registers
- Allows for autovectorization by GCC where necessary
- More clearly delineates our support set of targets, sticking true
  to forwards innovation, not necessarily legacy support

What CPUs do we lose that F11 supports?

- Intel i586 (all)
- Intel Pentium Pro
- Intel Pentium II
- Intel Pentium III
- 32-bit AMD Athlon
- AMD Geode
- VIA C3
- Transmeta Crusoe 

Does this lose the PAE/non-PAE kernel split?

- Alas, no.

Will a Fedora rebuilt in this manner work on ...

- OLPC 1.0? No.
- OLPC 1.5? Yes.
- Atom? Yes.

A seconday arch could be done for these older CPUs, if someone is interested
enough. 

Comments? Flames? Predictions of doom?

Bill

[1] http://bpepple.fedorapeople.org/fesco/FESCo-2009-02-05.html




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