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Date: Mon, 20 Jan 2003 09:04:57 -0800
From: "Martin J. Bligh" <mbligh@aracnet.com>
To: Ingo Molnar <mingo@elte.hu>, Erich Focht <efocht@ess.nec.de>
cc: Michael Hohnbaum <hohnbaum@us.ibm.com>,
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       Linus Torvalds <torvalds@transmeta.com>,
       linux-kernel <linux-kernel@vger.kernel.org>,
       lse-tech <lse-tech@lists.sourceforge.net>
Subject: Re: [patch] sched-2.5.59-A2
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> yes, but eg. in the idle-rebalance case we are more agressive at moving
> tasks across SMP CPUs. We could perhaps do a similar ->nr_balanced logic
> to do this 'agressive' balancing even if not triggered from the
> CPU-will-be-idle path. Ie. _perhaps_ the SMP balancer could become a bit
> more agressive.

Do you think it's worth looking at the initial load-balance code for 
standard SMP?

> ie. SMP is just the first level in the cache-hierarchy, NUMA is the second
> level. (lets hope we dont have to deal with a third caching level anytime
> soon - although that could as well happen once SMT CPUs start doing NUMA.)  

We have those already (IBM x440) ;-) That's one of the reasons why I prefer
the pools concept I posted at the weekend over just "nodes". Also, there
are NUMA machines where nodes are not all equidistant ... that can be
thought of as multi-level too.

> There's no real reason to do balancing in a different way on each level -
> the weight might be different, but the core logic should be synced up.
> (one thing that is indeed different for the NUMA step is locality of
> uncached memory.)

Right, the current model should work fine, it just needs generalising out
a bit.
 
M

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