P-IV is i386 or i686?

[Aleksandar Milivojevic]

Felipe Alfaro Solana wrote:
> RPM packages for i386 are targeted to any Intel 80386 processor or 
> newer. RPM packages for i686 are compiled using instructions from the 
> 80386 instruction set, but the code is optimized for an Intel Pentium or 
> newer processor.

i686 pacakges actually use i686 specific instructions, and will not work 
on older processors (i386, i486, and i586).  i386 packages are the ones 
that use i386-only instruction set, and scheduling of instructions is 
optimized for execution of i686 processors (since that is the 
architecture most people use these days).

The majority of packages for Fedora are compiled with i386 instruction 
set, since there doesn't seem to be any advantage in using extended 
instruction sets of newer processors (as was kindly pointed to me on 
several ocasions).  Only the packages that really benefit from extended 
instruction set are compiled for i586 and/or i686.  This basically boils 
down to instructions for atomic locking and the packages that are 
actually implementing locking for userland applications (or need to 
perform it on low level for themself), such as kernel and glibc.

-- 
Aleksandar Milivojevic <amilivojevic at pbl.ca>    Pollard Banknote Limited
Systems Administrator                           1499 Buffalo Place
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