Alan Cox wrote: > Likewise my own testing has always found that the Athlon really > doesn't care much how you order instructions. If you think about it > AMD have spent years dealing with everyone optimising for random intel > processor of the year and adapted appropriately. I have to agree with Alan on this. Having assembled Athlon-based clusters from Athlon's introduction until a year ago, the i686 (Pentium Pro) optimizations get you very close, like within 5%, of ideal on Athlon32. > Except on things like 3dnow and prefetch stuff the AMD really doesn't > seem to care. Plus any floating point. Athlon32/Athlon64/Opteron has 3 FPUs, two complex and one simple. Pentium II to Pentium IV has 2 FPUs, of which you can only do either one complex (while one is idle) or two simple. While the Athlon does a lot of run-time optimization via out-of-order execution and register renaming, the compile-time optimizations can affect things upto 40%. But that's more of an application thing -- maybe only a few GLibC calls (?). -- Bryan J. Smith, E.I. -- b.j.smith@xxxxxxxx
