On Tuesday 20 November 2007 13:02, Christoph Lameter wrote: > 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%?)
Small socket count systems are going to increasingly be NUMA in future. If CONFIG_NUMA hurts performance by that much on those systems, then the kernel is broken IMO. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
