On Sat, Apr 04, 2009 at 12:19:02PM -0700, Greg Lindahl wrote: > Exactly like shared-bus multiprocessors. > > The incremental method of solving this is what Opteron/Nehalem does.
None of these had to deal with hundreds or thousands of cores in a single socket yet (arguably GPGPU is pushing the envelope here, and I wonder how long they'll manage to avoid going embedded memory). SMP (shared global memory) in general would fall flat on its face well before kilocore, not even talking about mega or gigacore. > The more radical method is what Origin/Altix did. It all comes down to As long as it's shared-nothing message-passing which doesn't pretend to create an illusion of shared global memory it's ok. > how many pins you're willing to commit to memory and how few pins you > can squeeze a memory bus down to; once you bump up against that limit, > then you need an improvement in packaging, which is no more radical > than what Opteron/Nehalem or Origin/Altix did. And, of course, all I would call http://www.cc.gatech.edu/~loh/Papers/isca2008-3Ddram.pdf not your run-of-the-mill approach. Not radical, no. > this was invented before Opteron or Origin. > > The sky is not falling. Of course it isn't. Though I would like to see how Linux handles a megacore or a gigacore, each with a MByte or a couple of embedded memory, on a high-dimensional signalling mesh. -- Eugen* Leitl <a href="http://leitl.org";>leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
