sched-domains

sched-domains

[Andrew Morton]

Folks, I remain all in a dither over the sched-domains NUMA/SMT work which
has been in the -mm kernels for a while.

I have no concerns about its stability, but I do want to see general
agreement that this is the way to proceed, although of course it may need
enhancements/tuning later on.

In terms of performace testing results I believe everything has been
positive except for some testing which Andi did on the STREAM benchmark.

My question is: to what extent have the ia64 NUMA architectural people
reviewed this code, and what is the risk that someone will come along in
six months time saying we need to rip it all out?

Thanks.

Re: sched-domains

[John Hawkes]

From: "Andrew Morton" <akpm@osdl.org>
...
> My question is: to what extent have the ia64 NUMA architectural people
> reviewed this code, and what is the risk that someone will come along in
> six months time saying we need to rip it all out?

I am generally happy with the architecture of sched-domains.  The big
advantage I see for large Altix-like NUMA platforms is that much of the
scheduler policy decisions are parameterized in sched_domain fields and are
more easily tuned on a per-architecture and per-platform basis.  In
particular, it is easy to define additional scheduler domains that are larger
than a single node and smaller than all the CPUs in the system, each domain
having its own parameterized characteristics of load-balance frequency, etc.

John Hawkes