Re: NUMA scheduler (was: 2.5 merge candidate list 1.5)

From: Erich Focht (efocht@ess.nec.de)
Date: Mon Oct 28 2002 - 12:26:37 EST


On Monday 28 October 2002 17:57, Martin J. Bligh wrote:
> > I'm preparing a core patch which doesn't need the pool_lock. I'll send it
> > out today.
>
> Cool! Thanks,

OK, here it comes. The core doesn't use the loop_over_nodes() macro any
more. There's one big loop over the CPUs for computing node loads and
the most loaded CPUs in find_busiest_queue. The call to build_cpus()
isn't critical any more. Functionality is the same as in the previous
patch (i.e. steal delays, ranking of task_to_steal, etc...).

I kept the loop_over_node() macro for compatibility reasons with the
additional patches. You might need to replace in the additional patches:
numpools -> numpools()
pool_nr_cpus[] -> pool_ncpus()

I'm puzzled about the initial load balancing impact and have to think
about the results I've seen from you so far... In the environments I am
used to, the frequency of exec syscalls is rather low, therefore I didn't
care too much about the sched_balance_exec performance and prefered to
try harder to achieve good distribution across the nodes.

Regards,
Erich



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