[Beowulf] itanium vs. x86-64

Mark Hahn hahn at mcmaster.ca
Mon Feb 9 14:45:14 PST 2009

> I have been working on itanium machines for a year now and I actually found
> the hw pretty elegant and the dev software stack on top of it (compiler,
> profiler etc) pretty handy.

aren't all the same tools available on x86_64?  or were you referring to, eg,
something SGI-specific?

> but now with the Tukwila switching to the QuickPath, how do you guys think
> Itanium will perform in comparison to Xeon's and Opteron's ?

this change would be interesting if it meant that the next-gen numalink
box could take nehalems rather than ia64.  I can't really understand 
why Intel has stuck with ia64 this long - perhaps the economy will provide
the fig-leaf necessary to dump it.

(why am I down on ia64?  mainly the sense of unfulfilled promise: the ISA was
supposed to provide some real advantage, and afaikt never has.  the VLIW-ie
ISA was intended to avoid clock scaling problems created by CISC decode and
OOO, no?  but the ia64 seems to have only distinguished itself by relatively
large caches and offering cache-coherency hooks to SGI.  have other people 
had the experience ia64 doing OK on code with regular/unrollable/prefetchable 
data patterns, but poorly otherwise?)

regards, mark hahn.

More information about the Beowulf mailing list