> Mike Jagdis wrote:
>
> > Why? It is pretty easy to recognise all x86 varieties (other than the
> > early 486 clones) at run time and simply Do The Right Thing without
> > asking the user daft questions about whether they have microcode
> > bug #564 or working frozzle optimizations.
It is very easy to identify the CPU at run time but you can't do anything
about what you find. It's too late. To obtain optimum performance, you
need the code compiled to take advantage of a particular CPU. For
instance, a '486 doesn't give a damn about longword alignment. A pentium
does. You can't realign code at run time. It is possible to align buffers
at run time, but the overhead could be somewhat extreme. You can't just
build a kernel for the latest and greatest CPU because some internally-
locked instructions, which you really would like to use, are not supported
in a '386, etc., etc.
So with Intel, we have to make a kernel which will run with anything, then
rebuild the sources to take advantage of the platform's latest CPU
advances.
Cheers,
DJ
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Richard B. Johnson
Analogic Corporation
Email : rjohnson@analogic.com, johnson@analogic.com
Penguin : Linux version 2.1.44 on an i586 machine (66.15 BogoMips).
Warning : It's hard to stay on the trailing edge of technology.
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