Schedulability analysis for the abort-and-restart model
نویسنده
چکیده
In real-time systems, a schedulable task-set guarantees that all tasks complete before their deadlines. In functional programming, atomic execution provides the correctness of the program. Priority-based functional reactive programming (P-FRP) allows the usage of functional programming in the real-time system environment. The abort-and-restart (AR) is a scheme to implement P-FRP but an appropriate scheduling approach does not exist at the moment. Hence, efficient analysis is needed for the AR model. In this thesis, the schedulability analysis for the AR model is introduced and it shows that finding the critical instant for the AR model with periodic and sporadic tasks is intractable, and a new formulation is derived. Afterwards, a new priority assignment scheme is developed that has the performance close to the exhaustive search method, which is intractable for large systems. The technique of deferred preemption is employed and a new model, deferred abort (DA), provides better schedulability and dominates the nonpreemptive model. Lastly, a tighter analysis is introduced and the technique of the multi-set approach from the analysis of cache related preemption delay is employed to introduce a new approach, multi-bag. The multi-bag approach can apply to both the AR model and the DA model. In the experiments, the schedulability of the AR model is improved at each stage of the research in this thesis.
منابع مشابه
Improved Priority Assignment for the Abort-and-Restart (AR) Model
This paper addresses the scheduling of systems that implement the abort and restart (AR) model. The AR model requires that preempted tasks are aborted. As a result high priority tasks run quickly and shared resources need not be protected (as tasks only work on copies of these resources). However there is significant wastage as low priority tasks may be subject to a series of aborts. We show th...
متن کاملReal-Time Synchronization Protocols with Abortable Critical Sections
Making critical sections abortable is a promising approach to reducing priority inversions. To improve the schedulability of a system using abortable critical sections, the maximum number of abortions should be decreased. In this paper, we propose a real-time synchronization protocol named the ceiling abort protocol (CAP) which introduces a new priority-based abort scheme to the priority ceilin...
متن کاملSome Applications of Multiple Classes G-Networks with Restart
We show how to model system management tasks such as load-balancing and delayed download with backoff penalty using G-networks with restart.We useG-networks with a restart signal, multiple classes or positive customers, PS discipline and arbitrary PH service distribution. The restart signal models the possibility to abort a task and send it again after changing its class and its service distrib...
متن کاملTECHNICAL REPORT 95-02 Controlling Priority Inversion using Abortions
Making critical sections abortable is a promising approach to controlling priority inversions. To improve the schedulability of a system using abortions, the maximum number of abortions should be decreased. In this paper, we propose a real-time synchronization protocol named the selective abort protocol (SAP) which introduces a new abort scheme to the priority ceiling protocol. Our proposed sch...
متن کاملAchieving System-level Fault-tolerance with Controlled Resets
Embedded systems in safety-critical environments are continuously required to deliver more performance and functionality, leading to increased complexity and connectivity. Despite the fast growing complexity, guaranteeing safety is of the utmost importance. Nonetheless, platform-wide software verification is often expensive. Therefore, design methods that enable utilization of components such a...
متن کامل