On Wednesday 13 August 2003 15:49, Bill Davidsen wrote:
> On Mon, 28 Jul 2003, Andrew Theurer wrote:
> > Personally, I'd like to see all systems use NUMA sched, non NUMA systems
> > being a single node (no policy difference from non-numa sched), allowing
> > us to remove all NUMA ifdefs.  I think the code would be much more
> > readable.
>
> That sounds like a great idea, but I'm not sure it could be realized short
> of a major rewrite. Look how hard Ingo and Con are working just to get a
> single node doing a good job with interactive and throughput tradeoffs.

Actually it's not too bad.  Attached is a patch to do it.  It also does 
multi-level node support and makes all the load balance routines 
runqueue-centric instead of cpu-centric, so adding something like shared 
runqueues (for HT) should be really easy.  Hmm, other things: inter-node 
balance intervals are now arch specific (AMD is "1").  The default busy/idle 
balance timers of 200/1 are not arch specific, but I'm thinking they should 
be.  And for non-numa, the scheduling policy is the same as it was with 
vanilla O(1). 

> Once they get a good handle on identifying process behaviour, and I
> believe they will, that information could be used in improving NUMA
> performance, by sending not just 'a job" but "the right job" if it exists.
> I'm sure there are still a few graduate theses possible on the topic!

I do agree, but I think _what_ we pick is definitely 2.7 work.  All I'd like 
to see for 2.6 is a very nice, unified framework to build on.

As for 1cpu/node case I think this second patch (on top of first) will take 
care of it; however I have not had a chance to test on AMD yet.

-Andrew Theurer