Jeff Garzik wrote:
>
> Jeff Merkey wrote:
> > here are tests for all this in the feature flags for intel and
> > non-intel CPUs like AMD -- including MTRR settings. All of this could
> > be dynamic. Here's some code that does this, and it's similiar to
> > NetWare. It detexts CPU type, feature flags, special instructions,
> > etc. All of this on x86 could be dynamically detected.
>
> Jeff, I think you miss the point that 100% dynamic detection comes with
> a penalty over the current system.
>
> Using CONFIG_M586 enables us to compile with Pentium-specific
> instructions, and eliminate any code specific to 386's or 486's. This
> includes inlining Pentium-specific code into drivers and the core kernel
> where possible, for the maximum possible performance. Your scheme
> doesn't work because of all the inlined code, nor does it support
> maximum performance code on all processors without massive code bloat...
>
> You do bring up a good point though. Users compile their own kernels to
> get the advantages I describe above. Vendors, on the other hand, must
> compile one-size-fits-all generic kernels. Your expertise and
> assistance would definitely benefit this case.
>
We need a format that allow multiple executable segments to be combined
in a single executable and the loader have enough smarts to grab the
right one based on architecture. two options:
1. extend gcc to support this or rearragne linux into segments based on
code type
2. Use PE.
Jeff
> One change I would like to make in 2.5.x along these lines -- the Alpha
> AXP port allow one to define either CONFIG_ALPHA_GENERIC -- support all
> processors/machines -- or CONFIG_ALPHA_$MYMACHINE. It would be nice to
> follow that model for x86 too. Currently, when I select CONFIG_M586, I
> get code for 686, etc. There is no way to simply say "Pentium and
> nothing else".
>
> Jeff
>
> --
> Jeff Garzik | "When I do this, my computer freezes."
> Building 1024 | -user
> MandrakeSoft | "Don't do that."
> | -level 1
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