Messages in this thread | | | Date | Sat, 11 Feb 2006 15:04:13 +1100 | From | Peter Williams <> | Subject | Re: [rfc][patch] sched: remove smpnice |
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Peter Williams wrote: > Andrew Morton wrote: > >> "Siddha, Suresh B" <suresh.b.siddha@intel.com> wrote: >> >>> b) On a lightly loaded system, this can result in HT scheduler >>> optimizations >>> being disabled in presence of low priority tasks... in this case, >>> they(low >>> priority ones) can end up running on the same package, even in the >>> presence of other idle packages.. Though this is not as serious as >>> "a" above... >>> > > I think that this issue comes under the heading of "Result of better > nice enforcement" which is the purpose of the patch :-).
On the assumption that this enforcement is considered to be too vigorous, I think that it is also amenable to a fix based on a new biased_load() function by replacing the (*imbalance < SCHED_LOAD_SCALE) test with (biased_load(*imbalance, busiest) == 0) and (possibly) some modifications within the if statement's body (most notably replacing the NICE_TO_BIAS_PRIO(0) expressions with (busiest->prio_bias / busiest->nr_running) or something similar).
This change would cause no change in functionality in the case where all tasks are nice==0.
Peter -- Peter Williams pwil3058@bigpond.net.au
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