On Tue, Oct 4, 2016 at 1:43 PM, <Gernot.Heiser@data61.csiro.au> wrote:

I wouldn’t conclude that the socket is the smallest worthwhile partition. I think we’re lucky that we got the BKL to work across a socket, but you can argue whether that is even too big. I think the smallest worthwhile partition is where you physically share a cache. (Latest-generation Intel boxes have a distributed L3 that is made to look like a shared one.)

Right, so as core count and cache grows, and coupling between a single CPU's cores becomes looser, it'll be worth having more than one partition per socket.

Is the closest thing to loosely coupled cores at mobile (or at least sub-server) scale right now big.LITTLE? Interesting that Apple's A10 Fusion "fixes" big.LITTLE by sharing its L2 between both pairs of cores.

Thanks,

Jeff