Re: Increase number of tasks

MOLNAR Ingo (mingo@chiara.csoma.elte.hu)
Tue, 1 Dec 1998 23:12:16 +0100 (CET)


On Tue, 1 Dec 1998, Rik van Riel wrote:

> help since the CPU spent on the standard scheduler is
> dependant on NR_TASKS [...]

i find this comment disturbingly inaccurate. first, it's not dependent on
NR_TASKS, but nr_tasks, which is different. (even if we are talking about
many processes, the difference should be mentioned)

but more importantly, the dependency is very small, and only scales with
the number of timeslices expired. (ie. constant and independent of the
number of schedules per second! not even sched_yield() is an exception
anymore. It's rare to be triggered, and even if it gets triggered, most
likely the system is going idle so it doesnt matter how much time we
spend.)

Third, it's a feature which makes sleeping tasks gain timeslices
logaritmically with time.

-- mingo

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