Messages in this thread | | | Date | Thu, 14 Aug 2003 16:00:37 -0400 | From | Timothy Miller <> | Subject | Re: [PATCH] O12.2int for interactivity |
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William Lee Irwin III wrote: > On Thu, 14 Aug 2003 16:09, William Lee Irwin III wrote: > >>>"scale" on which scheduling events should happen, and as tasks become >>>more cpu-bound, they have longer timeslices, so that two cpu-bound >>>tasks of identical priority will RR very slowly and have reduced >>>context switch overhead, but are near infinitely preemptible by more >>>interactive or short-running tasks. >> > > On Thu, Aug 14, 2003 at 04:59:33PM +1000, Con Kolivas wrote: > >>Actually the timeslice handed out is purely dependent on the static priority, >>not the priority it is elevated or demoted to by the interactivity estimator. >>However lower priority tasks (cpu bound ones if the estimator has worked >>correctly) will always be preempted by higher priority tasks (interactive >>ones) whenever they wake up. > > > So it is; the above commentary was rather meant to suggest that the > lengthening of timeslices in conventional arrangements did not penalize > interactive tasks, not to imply that priority preemption was not done > at all in the current scheduler.
If my guess from my previous email was correct (that is pri 5 gets shorter timeslide than pri 6), then that means that tasks of higher static priority have are penalized more than lower pri tasks for expiring.
Say a task has to run for 15ms. If it's at a priority that gives it a 10ms timeslice, then it'll expire and get demoted. If it's at a priority that gives it a 20ms timeslice, then it'll not expire and therefore get promoted.
Is that fair?
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