Messages in this thread | | | Date | Tue, 5 Jun 2001 22:05:47 +0300 (IDT) | From | Tsafrir Dan <> | Subject | Re: the value of PROC_CHANGE_PENALTY |
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On Mon, 4 Jun 2001, Mark Hahn wrote:
> > am I correct ? > > and if so, is this what the authors meant, or did they simply forget > > to update PROC_CHANGE_PENALTY's value when moving from 2.2 to 2.4 ? > > I don't believe anyone has proposed a relation between nice > and cpu-affinity; the latter has always been a fairly arbitrary > constant.
I see, but even so, in linux-2.2 this arbitrary constant allows a non realtime task to migrate, and totally prohibits it in linux-2.4 (unless some other cpu is idle). i.e. maybe there is no relation between the max value of the static priority and PROC_CHANGE_PENALTY, but you get a scheduler that behaves quite differently when you change one without the other.
I think that if it's indeed an arbitrary value, then it should have been modified along with the modification of the quantum's length, because this way the 2.2 behavior (which I assume somebody adopted for a reason) would have remained the same.
However, if you say that PROC_CHANGE_PENALTY does somehow embody the cpu-time wasted because of migration (due to cache etc.) regardless of the quantum's length, then PROC_CHANGE_PENALTY should probably remain the same and I got my answer.
Is this what you mean ?
thanks, Dan.
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