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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