Re: [PATCH] Load balancing problem in 2.6.2-mm1

[Martin J. Bligh]

>> Can we keep current behaviour default, and if arches want to
>> override it they can? And if someone one day does testing to
>> show it really isn't a good idea, then we can change the default.
>> 
>> I like to try stick to the fairness first approach.
>> 
>> We got quite a few complaints about unfairness when the
>> scheduler used to keep 2 on one cpu and 1 on another, even in
>> development kernels. I suspect that most wouldn't have known
>> one way or the other if only top showed 66% each, but still.
> 
> Stupid question:  Does the balancing consider process priority?  Is it 
> unfair to have two lower pri tasks always on one cpu while the highest 
> pri of the three is always by itself?

No, it doesn't take account of that. We've discussed that before at some 
point, and yes, I  think it's wrong, but on the other hand, we want to be 
reasonably fast at deciding what to take, and there are a whole bunch of 
other criteria that we ought to be taking account as well - it's difficult.

M.

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