Dynamic Partitioning Based Scheduling of Real-Time Tasks in Multicore Processors

Abstract

Existing real-time multicore schedulers use either global or partitioned scheduling technique to schedule real-time tasks. Partitioned scheduling is a static approach in which, a task is mapped to a per-processor ready queue prior to scheduling it and it cannot migrate. Partitioned scheduling makes ineffective use of the available processing power and incurs high overhead when real-time tasks are dynamic in nature. Global scheduling is a dynamic scheduling approach, where the processors share a single ready-queue to execute the highest priority tasks. Global scheduling allows task migration which results in high scheduling overhead. In this paper, we present a dynamic partitioning based scheduling of real-time tasks, called DP scheduling. In DP scheduling, jobs of tasks are assigned to cores when they are released and remain in the same core till they finish execution. The partitioning in DP scheduling is done based on the slack time and priority of jobs. If a job cannot be allocated to any core, then it is split, and executed on more than one core. DP scheduling technique attempts to retain good features of both global and partitioned scheduling without compromising on resource utilization, and at the same time, also tries to minimize the scheduling overhead. We have tested DP scheduling technique with EDF scheduling policy at each core, and we term this scheduling algorithm as DP-EDF. The performance of DP-EDF scheduling algorithm has been evaluated using simulation study and its implementation in LITMUS RT on a 64-bit intel processor with eight logical cores. Both simulation and experimental results show that DP-EDF scheduling algorithm has better performance in terms of resource utilization, and comparable or better performance in terms of scheduling overhead in comparison to contemporary scheduling algorithms.

Real-time Scheduling Algorithm with Execution Right Delegation for Multiprocessor

“…Uniprocessor ERD and our previous study [4] only support one privileged task. * 9 [19] requires a dedicated server processor for migration and on-line partitioning. In contrast, in mERD, migration is processed in the order of m × max(length(slp q)) ≒ m × n in our pseudo code.…”

“…Dynamic Partitioning (DP) [19] is based on the job-levelmigration EDF model. When a job is released, it is assigned to some processor.…”

Adaptive partitioning of real-time tasks on multiple processors

“…2 ) is known to be optimal for fixed-job-priority algorithms [1]. 1 Although the proposed technique is a form of dynamic partitioning, the name "adaptive partitioning" is used to avoid confusion with a previous work [24] that used the term "dynamic partitioning" to indicate a completely different algorithm (based on making a distinction between real-time cores and non-real-time cores, and using a dedicated scheduling core to perform on-line admission control on the arriving jobs).…”

A Survey of the Heterogeneous Computing Platform and Related Technologies

“…A research [20] present a technology to divide and dispatch tasks. If a task cannot be dispatched to a core to execute, it will be divided into several subtasks and be dispatched to several different cores concurrently.…”