Today I had a discussion about SMP and NUMA with my students and I realized that Opertons really are NUMA as memory accesses are non-uniform (I was under the impression that SMP not necessarily imply UMA and that SMP/NUMA are othogonal aspects).
Anyone knows the cost (in case of an Opteron) of a remote memory access vs. a local memory access? Is the difference significant? And if it matters, is DragonFly already aware about which memory locations are local to which CPU, and is this information used in the memory allocator? (IIRC the memory allocator is CPU localized, but that does not automatically imply that it knows about remote/local memory locations). I think that's the only place where this information is really important. The userland scheduler of course could take advantage from it as well. Regards, Michael
