Re: [PATCH 2/3] FUTEX : introduce private hashtables

Ulrich Drepper
2007-03-15T21:09:52Z

On 3/15/07, Nick Piggin <nickpiggin@yahoo.com.au> wrote:
> There should be little contention on the memory in the global hash anyway,
> because we can roughly reduce contention as a factor of hash-size/cacheline-size.
>
> What we will have are cache misses on the global table... but we're going to
> get cache misses on those private tables as well.

I'm thinking about NUMA cases. If you have private tables for a
process which is pinned to some cluster in a NUMA machine the table is
local to the node. If you have a global table you cannot optimize
your application for such a situation because at least some of the
pages of the global table are remote.