Changing the default 32-bit x86 arch for Fedora 12

Gregory Maxwell gmaxwell at gmail.com
Mon Jun 15 21:29:11 UTC 2009


On Mon, Jun 15, 2009 at 1:53 PM, Bill Nottingham<notting at redhat.com> wrote:
[snip]
> - Faster and more consistent FP math by using SSE2 registers

I doubt having consistently lower FP precision is anything many users
are asking for. The few that do can usually take care of themselves.

> - Allows for autovectorization by GCC where necessary

Autovectorization is seldom effective, alas.
SSE2 is part of the x86_64 basic arch.

> - More clearly delineates our support set of targets, sticking true
>  to forwards innovation, not necessarily legacy support

If thats the case why maintain x86 at all?

Take your answer and now apply it to why fedora should maintain
support for x86 CPUs without SSE2.

In my case, this change would eliminate all of my x86 (not _64)
systems save one pentium 4 box which is boxed up and turned off
because its such a waste of power.

The benefit of constraining x86 to SSE2 enabled chips is fairly small.
The benefit of dropping x86 entirely would be much much greater. Of
course, the cost is much greater too, but I believe that the latter
still maintains the better cost/benefit ratio.

Though I don't think either should be done.




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