Papers by DR HABIBAH ISMAIL
MATEC Web of Conferences, 2019
Generally, multiprocessor real-time scheduling algorithm fall into two basic approaches, partitio... more Generally, multiprocessor real-time scheduling algorithm fall into two basic approaches, partitioned and global. The hybrid solution that we proposed applies the partitioned scheduling approach to the task set until all processors have been filled. The remaining tasks are then scheduled using the global scheduling approach. The idea of a hybrid scheduling approach to ameliorate limitations of partitioned and global approaches. Studies have shown that most prior research on hybrid multiprocessor real-time scheduling has been confined to hard and soft real-time tasks. In fact, the implementation of hybrid approach and the performance of such algorithms in comparison to partitioned and global approaches have not been fully answered by previous studies. This paper performs experimental evaluation of our proposed hybrid multiprocessor scheduling approach, R-BOUND-MP-NFRNS and RM-US (m/3m-2) with multiprocessor response time test, with one of the best scheduling approach from partitioned ...
Jurnal Teknologi, 2015
Real-time systems or tasks can be classified into three categories, based on the “seriousness” of... more Real-time systems or tasks can be classified into three categories, based on the “seriousness” of deadline misses – hard, soft and weakly hard real-time tasks. The consequences of a deadline miss of a hard real-time task can be prohibitively expensive because all the tasks must meet their deadlines whereas soft real-time tasks tolerate “some” deadline misses. Meanwhile, in a weakly hard real-time task, the distribution of its met and missed deadlines is stated and specified precisely. As real-time application systems increasingly come to be implemented upon multiprocessor environments, thus, this study applies multiprocessor scheduling approach for verification of weakly hard real-time tasks and to guaranteeing the timing requirements of the tasks. In fact, within the multiprocessor, the task allocation problem seem even harder than in uniprocessor case; thus, in order to cater that problem, the sufficient and efficient scheduling algorithm supported by accurate schedulability anal...
Performance Evaluation of the Weakly Hard Real-Time Tasks for Global Multiprocessor Scheduling Approach
2021 IEEE Asia-Pacific Conference on Computer Science and Data Engineering (CSDE), 2021
Real-time systems can be classified into three categories, based on the “seriousness” of deadline... more Real-time systems can be classified into three categories, based on the “seriousness” of deadline misses either by hard, soft, or weakly hard real-time tasks. The consequences of deadlines miss for a hard real-time task cannot be tolerated because some failure can affect the system performance whereas some deadline misses can be tolerated for soft real-time tasks. Meanwhile, in a weakly hard real-time task, the distribution of its met and missed deadlines is stated and specified precisely. Due to the complexity and significantly increased functionality in system computation, attention has been given to multiprocessor scheduling. Studies have shown that current multiprocessor scheduling of weakly hard real-time tasks used imprecise computation model based on iterative algorithms. This algorithm decomposed into two parts; mandatory and optional parts, unfortunately, the result analysis is precise only if its mandatory and optional parts are both executed. Even, the use of hierarchical scheduling algorithm, such as two-level scheduling under PFair algorithm may cause high overhead due to frequent preemptions and migrations. Furthermore, this algorithm incurs significant run-time overhead due to their quantum-based scheduling. In order to cater for the limitations and stated problems, an alternative multiprocessor scheduling approach, called global scheduling is proposed. The proposed scheduling approach aims to improve the probability of deadline satisfactions as much as possible and at the same time achieve a higher utilization of the task sets, with less task migrations. Thus, in this paper, performance measurement parameters are used as performance evaluation of the proposed scheduling approach.
In relation to real-time systems, hard real-time and soft real-time systems are based on “miss re... more In relation to real-time systems, hard real-time and soft real-time systems are based on “miss restriction” and “miss tolerance”, respectively. However, a weakly hard real-time system integrates both these requirements. The problem with these systems is the limitation of the scheduling analysis method which only uses the traditional scheduling approach. Besides that, the current framework has problems with the complexity and predictability of the systems. This paper proposes a scheduling analysis framework based on, namely: the suitability of scheduling algorithms, the weakly hard real-time modelling and genetic algorithm approach for predicting the weakly hard real-time tasks. Initially, the best fitting specification of a weakly hard real-time system was integrated into the proposed framework and tested in the Modeling and Analysis of Real-Time Embedded systems (MARTE) profile. Sequence diagram complexity factor metrics were used to measure the behavioural complexity of the UML Pr...
A Hybrid Multiprocessor Scheduling Approach for Weakly Hard Real-Time Tasks
There are two major strategies to schedule real-time tasks in multiprocessor systems; partitionin... more There are two major strategies to schedule real-time tasks in multiprocessor systems; partitioning and global scheduling. The partitioning approach has acceptable overhead but cannot guarantee to be optimal. The global approach can provide this guarantee but it has considerable overhead. Thus, a multiprocessor real-time scheduling approach for weakly hard real-time tasks is proposed that employs hybrid scheduling. Studies have shown that current multiprocessor scheduling of weakly hard real-time tasks used imprecise computation model based on iterative algorithms. This algorithm decomposed into two parts; mandatory and optional, unfortunately, the result analysis is precise only if its mandatory and optional parts are both executed. Even, the use of hierarchical scheduling algorithm, such as two-level scheduling under PFair algorithm may cause high overhead due to frequent preemptions and migrations. In this paper, an alternative scheduling approach will be proposed, which is, its c...
IOP Conference Series: Materials Science and Engineering, 2020
One way to minimizing resource requirements is through the careful management and allocation, in ... more One way to minimizing resource requirements is through the careful management and allocation, in example, scheduling. Research on weakly hard real-time scheduling on multiprocessor has been extremely limited; most prior research on real-time scheduling on weakly hard real-time has been confined to uniprocessors. The need for multiprocessor is due to issues that impose limits on the performance of a single processor. As real-time application systems increasingly come to be implemented upon multiprocessor environments, thus, this study applies multiprocessor scheduling approach for verification of weakly hard real-time tasks and to guaranteeing the timing requirements of the tasks. In fact, within the multiprocessor, the task allocation and migration problems seem even harder than in uniprocessor case; thus, in order to cater that problem, the sufficient and efficient scheduling algorithm supported by accurate schedulability analysis technique is present to provide weakly hard real-ti...
A weakly hard real-time tasks on global scheduling of multiprocessor systems
2015 9th Malaysian Software Engineering Conference (MySEC), 2015
Real-time tasks can be classified into three categories, based on the “seriousness” of deadline m... more Real-time tasks can be classified into three categories, based on the “seriousness” of deadline misses - hard, soft and weakly hard real-time tasks. The consequences of a deadline miss of a hard real-time task cannot be accepted whereas soft real-time tasks tolerate “some” deadline misses. While, in a weakly hard real-time task, the distribution of its met and missed deadlines is stated and specified precisely. Due to the complexity and significantly increased functionality in system computation, attention has been given to multiprocessor scheduling, comprised of several processors. Due to the fact that in multiprocessor, there have more than one processor, algorithms which can cater higher computational complexity for task allocation and for task migration are highly required. Thus, the sufficient and efficient scheduling algorithm supported by accurate schedulability analysis technique is presented to provide weakly hard real-time guarantees. In this paper, a schedulability analysis to schedule weakly hard real-time tasks has been proposed by using the global multiprocessor scheduling technique, called multiprocessor response time analysis combining with the exact analysis, named hyperperiod analysis and deadline models; weakly hard constraints and μ-pattern under static priority scheduling. Then, the Matlab simulation tool is used in order to validate the result of analysis. From the performance evaluation results, it proved that the proposed approach is satisfied the tasks deadlines with less number of misses.
Communications in Computer and Information Science, 2011
A real-time system is one in which the temporal aspects of its behaviour are part of their specif... more A real-time system is one in which the temporal aspects of its behaviour are part of their specification. The problem with traditional real-time specification is no guarantees on when and how many deadlines may be missed can be given to the tasks because their specification is focused on met all the deadlines and cannot missed it, otherwise the tasks is totally failed. Thus, the weakly hard specification solve this problem with define a gradation on how the deadlines can be missed while still guaranteeing the tasks meets their deadlines. In this paper, a review has been made on the three specifications of real-time systems which is losses or missed of the deadlines can be permitted occasionally. Three criteria used in the evaluation are the process model, temporal specifications and predictability. These three criteria were chosen because the tasks in real-time systems are usually periodic in nature, have timing constraints like deadlines and the behaviour of the systems must be predictable. The three specifications we reviewed in this paper are the skip constraints known as skip factor s, (m,k)-firm deadlines and the weakly hard constraints. The objective of review is to find which specification is better in order to predict the behaviour of a task based on those three criteria. Based on our review, it is concluded that the weakly hard constraints outperforms the two conventional specifications of weakly hard real-time systems using that three criteria based on our evaluation by using a mobile robot case study due to its capability to specify in a clear of the distribution of deadlines met and missed.
2014 8th. Malaysian Software Engineering Conference (MySEC), 2014
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Papers by DR HABIBAH ISMAIL