Messages in this thread | | | Date | Sat, 02 Apr 2005 12:07:27 +1000 | From | Nick Piggin <> | Subject | Re: [Patch] sched: remove unnecessary sched domains |
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Siddha, Suresh B wrote: > Appended patch removes the unnecessary scheduler domains(containing > only one sched group) setup during the sched-domain init. > > For example on x86_64, we always have NUMA configured in. On Intel EM64T > systems, top most sched domain will be of NUMA and with only one sched_group in > it. > > With fork/exec balances(recent Nick's fixes in -mm tree), we always endup > taking wrong decisions because of this topmost domain (as it contains only > one group and find_idlest_group always returns NULL). We will endup loading > HT package completely first, letting active load balance kickin and correct it. > > In general, this patch also makes sense with out recent Nick's fixes > in -mm. >
Yeah, this makes sense. We may want to add some other criteria on the removal of a domain as well (because some of the domain flags do things that don't use groups).
I don't like so much that we'd rely on it to fix the above problem. There are a general class of problems with the fork/exec balancing in that it only works on the top most domain, so it may not spread load over lower domains very well.
I was thinking we could fix that by running balance on fork/exec multiple times from top to bottom level domains. I'll have to measure the cost of doing that, because it may be worthwhile.
Thanks
-- SUSE Labs, Novell Inc.
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