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

Martin J. Bligh
2004-02-09T16:43:32Z

>> 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.