Re: [RFC][PATCH 00/26] sched/numa

Peter Zijlstra
2012-03-19T11:31:21Z

On Mon, 2012-03-19 at 12:12 +0100, Peter Zijlstra wrote:
> Also, if you go scan memory, you need some storage -- see how aa grows
> struct page, sure he wants to move that storage some place else, but the
> memory overhead is still there -- this means less memory to actually do
> useful stuff in (it also probably means more cache-misses since his
> proposed shadow array in pgdat is someplace else).

Going by the sizes in aa's patch, that's 96M of my 16G box gone. That
puts HPC people in a rather awkward position of having to choose between
more memory and slightly smarter kernel. I'm thinking they're going to
opt for going the way they are now (hard affinity/userspace balancers)
and use the extra memory.

This even though typical MPI implementations use the multi-process
scheme, so the simple home-node approach I used works just fine for
them.