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SubjectRe: [1/4] better i386 CPU selection
On Fri, Jan 16, 2004 at 04:01:33PM -0800, Andrew Morton wrote:
>...
> I must say that I'm a bit wobbly about Adrian's recent patches, simply
> because of the overall intrusiveness and conceptual changes which they
> introduce.

The only patch where I'd say this really applies to is
better-i386-cpu-selection.patch .

I'm really happy that you added it in the latest -mm and I'm even more
happy that I haven't yet heard of any major breakage it has caused.

But it's your decision whether you like this patch or prefer to drop it.

> Remind me again, what did they buy us?

The main effect is that better-i386-cpu-selection.patch makes it easier
for people who configure kernels that should work on different CPU
types. A user (= person compiling his own kernel) does no longer need
any deeper knowledge when e.g. configuring a kernel that should run on
both an Athlon and a Pentium 4 - he simply selects all CPUs he wants to
support in his kernel.

As a side effect, this patch allows further optimizations based on the
fact that e.g. a kernel for an i386 no longer needs to support an Athlon
which can be used to omit support for non-selected CPUs [1].

cu
Adrian

[1] e.g. there's no need to include arch/i386/kernel/cpu/amd.c in your
kernel if the kernel should only run on a 386;
I made two such example patches that are _way_ too ugly for merging
but show that this CPU selection scheme makes some more space
savings possible

--

"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed

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