Probabilistic task model

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Sophie Quinton
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Probabilistic task model

Post by Sophie Quinton » Mon Nov 06, 2017

[This problem was presented by Peter Zijlstra during his ECRTS'17 keynote talk, see slide 13]

Probabilistic task model.

There are a number of places where probabilistic (like) things pop up.
  • unprivileged GRUB would require a per-task limit on allows overrun
  • measurement based WCET, typically results in a distribution of sorts
  • SoftRT many stream workloads that want to maximize machine utilization, lower WCET budget to increase efficiency but then rely on overrun / unused bandwidth reclaim to deal with peaks.
If we extend the task model with 1 more variable that is a 'variance' on budget, for example a 0-sum limit on overrun (overrun is added to the sum, and underrun subtracted from the sum and is limited to [0,x]) can this be usefully employed by the scheduling function?

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