On Mon, 19 Nov 2007, H. Peter Anvin wrote:
You're making the assumption here that NUMA = large number of CPUs. This
assumption is flat-out wrong.
Well maybe. Usually one gets to NUMA because the hardware gets too big to be handleed the UMA way.
On x86-64, most two-socket systems are still NUMA, and I would expect that
most distro kernels probably compile in NUMA. However,
burning megabytes of memory on a two-socket dual-core system when we're
talking about tens of kilobytes used would be more than a wee bit insane.
Yeah yea but the latencies are minimal making the NUMA logic too expensive for most loads ... If you put a NUMA kernel onto those then performance drops (I think someone measures 15-30%?)