1 / 3

Comprehensive Analysis of Complex Hierarchical Scheduling for Real-Time Systems

This study delves into complex hierarchical scheduling involving ten tasks with varying burst times and jitter. It discusses three primary scheduling policies: Rate Monotonic, Earliest Deadline First, and Fixed Priority. The framework considers preemptive and independent tasks with deadlines equal to, less than, and greater than their periods, ensuring a total utilization of 98.5%. The paper also examines the periodic server model, where tasks serve as polling servers, checking resources and managing workloads preemptively. A thorough analysis determines the minimum required processor speed for schedulability.

riva
Télécharger la présentation

Comprehensive Analysis of Complex Hierarchical Scheduling for Real-Time Systems

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Problem 11: Complex Hierarchical Scheduling • 10 Tasks • - with jitter • - with bursts • - deadline = period • - deadline < period • deadline > period • preemptive & independent • 3 Scheduling Policies • - Rate Monotonic • - Earliest Deadline First • - Fixed Priority • Hierarchical Scheduling • Static & Dynamic Polling Servers • Total Utilization: 98.5% Full Processor Priority 4 Priority 1 FP SPS EDF T1 T4 Priority 3 DPS Priority 2 T2 T3 EDF RM T5 T6 T7 T8 T9 T10 Schedulable? Min. req. processor speed?

  2. Real-Time Load Specification pSPS = 4 (period) pDPS = 3 (period) eSPS = 1 (execution share) eDPS =1 (execution share) dSPS = 4 (deadline) dDPS = 3 (deadline)

  3. Periodic Server • A polling server can be thought of as a periodic task T (p, e). • When the server-task T is selected to run by the scheduler, the server-task checks whether workload is waiting to be processed by the server. • If yes, the server will provide e resources to process the waiting workload. • If no work is available for the server, the task will immediately be finished, i.e. the server will not check for arriving work anymore until the next period starts. • While the server is processing, it is preemptable. When it is preempted, it is put back into the ready-queue. • If the server could not provide e resources during a time interval T, even though there was always enough work available, then this is treated the same as a deadline-miss. I.e. the system is considered to be not schedulable.

More Related