A novel task scheduling algorithm for real time systems

This paper investigates the task scheduling problem in the oontext of reservation-based real-time systems that provide quality of service (QoS) guarantees. In such a system, each incoming task specifies a rate of progress requirement on the task's execution that must be met by the system in order for the computation to be deeemed usable. A new metric, called granularity, is introduced that quantifies both the maximum slowdown and the variance in execution rate that the task allows. This metric generalizes the stretch metric used in recent research on task scheduling. An online preemptive scheduling algorithm is presented that achieves a competitive ratio of g(1 - r) for every set of tasks with maximum rate r and minimum granularity g. This result generalizes a previous result based on the stretch metric that showed that a competitive ratio of (1 - r) is achievable for the case when g = 1.

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Performance Based Improvement of the CPU by reducing the Real-Time Interrupt Latency using the PPTS Algorithm

IMS Manthan (The Journal of Innovations) ◽

10.18701/imsmanthan.v8i2.5127 ◽

2015 ◽

Vol 8 (2) ◽

Author(s):

Lavanya Dhanesh ◽

Dr. P. Murugesan

Keyword(s):

Real Time ◽

Task Scheduling ◽

Scheduling Algorithm ◽

Research Work ◽

Priority Assignment ◽

The Real ◽

Latency Reduction ◽

Task Scheduling Algorithm ◽

Switching Delay ◽

Time Systems

The main objective of the research is to improve the performance of the CPU at software level by reducing the Interrupt Latency of the Real time systems. Interrupt Latency provides an important metric in increasing the performance of the Real Time Kernal. So far the research has been investigated with respect to real-time interrupt latency reduction using non-pre-emptive task scheduling algorithms. A general disadvantage of the non-preemptive discipline is that it introduces additional blocking time in higher priority tasks, so reducing schedulability. If the interrupt latency is increased, the task switching delay shall be increasing with respect to each task. Hence most of the research work has been focussed to reduce interrupt latency by using the Pre-emptive Task scheduling algorithm. Based on the literature survey, A Deadline Monotonic Priority Assignment technique is used to reduce the latency with respect to the deadline. Deferred pre-emption scheduling and Fixed pre-emptive scheduling algorithm are used to reduce the interrupt latencies based on the queue fixed to the priority of the tasks to be handled. Here we suggest a new algorithm named “Priority Preemptive task scheduling algorithm” which preempts and serve the task with highest priority and also concentrates on the low priority tasks during the buffering time of the higher priority tasks.

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Review Paper on Fault Tolerant Scheduling in Multicore System

VFAST Transactions on Software Engineering ◽

10.21015/vtse.v13i2.509 ◽

2018 ◽

pp. 75-83

Keyword(s):

Real Time ◽

Fault Tolerant ◽

Scheduling Algorithm ◽

Real Time Systems ◽

Recovery Method ◽

Agricultural Vulnerability ◽

Task Scheduling Algorithm ◽

Multicore System ◽

User Space ◽

Time Systems

In this paper, it was discussed about various fault tolerant task scheduling Algorithm for the multicore system based on hardware and software. Blend of triple module redundancy and double module redundancy considering Agricultural vulnerability factor other than EDF and LLF scheduling algorithms were used to create hardware-based algorithm. Most of the real-time systems used shared memory as dominant part. Low overhead software-based fault tolerance approach could be implemented at user space level so that it did not require any changes at an application level. Redundant multithread processes were used which could detect soft recover from the errors and could recover from them giving low overhead, fast error mechanism recovery, and detection. The overhead incurred by this method ranged from 0 to 8% for selected benchmarks. Another system used for scheduling approach in real-time systems was hybrid scheduling. Dynamic fault tolerating scheduling gave high feasibility where task critically was used to select the fault recovery method type in order to tolerate maximum no. of faults.

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