On Thu, Sep 30, 2004 at 06:39:28PM -0700, mmarion@qualcomm.com wrote:
On 30 Sep, Andi Kleen wrote:
The binaries shipped in x86-64 Linux distributions should be already pretty well optimized for K8. It's unlikely you can get much improvement
They're not... just look at my simple openssl comparisons: http://www.miguelito.org/openssl.
openssl may be a special case because it uses custom assembler optimizations. I haven't checked, but I remember at some point there were quite some subtle bugs in the assembler functions, so it's possible that the SUSE rpm takes an conservative but safe approach.
The good news (for AMD and fans.. :) ) is that amd chips get a huge boost at recompile. Em64t gets only a little.
My guess is the stuff was compiled with the most generic x86_64 support, much like many distros will build some things for i386 (or i586 mostly these days I guess) instead of optimized more.. in order to support the most people OOTB.
The K8 is the i386 equivalent on x86-64. Most generic support is currently K8 with 3dnow! off. -Andi