Why are there only i686 and i586 Version of glibc and kernel?

Jakub Jelinek jakub at redhat.com
Mon May 31 14:10:26 UTC 2004


On Mon, May 31, 2004 at 04:50:59PM -0400, Balint Cristian wrote:
> > Starting with FC3, .i386.rpm and .i686.rpm packages will be compiled
> > with -march{3,6}86 -mtune=pentium4, so although they will run on
> > i386 (resp. i686), they will be optimized for P4 (Athlons and newer AMD
> > chips run P4 optimized code without noticeable performance hit).
>
> Is there difference betwwen -mtune=pentium4 and -mtune=athlon ?
> Pentium4 sounds intel-ish centric but what about AMD ?.

Yes, there is.  The thing is, Intel chips are far more sensitive to
instruction scheduling than AMD chips.
So, if you run code tuned for AMD on P4, the performance hit is big,
if you run P4 optimized code on AMD, the performance hit compared to
running AMD tuned code on AMD is really small.

	Jakub





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