## Sensitivity Analysis for Fixed-Priority RealTime Systems (2006)

### Cached

### Download Links

Venue: | BNB06] [CKT03] [FGB01] [HHJ |

Citations: | 23 - 7 self |

### BibTeX

@INPROCEEDINGS{Bini06sensitivityanalysis,

author = {Enrico Bini and Marco Di Natale and Giorgio Buttazzo and Scuola Superiore Sant’anna},

title = {Sensitivity Analysis for Fixed-Priority RealTime Systems},

booktitle = {BNB06] [CKT03] [FGB01] [HHJ},

year = {2006}

}

### OpenURL

### Abstract

At early stages in the design of real-time embedded applications, the timing attributes of the computational activities are often incompletely specified or subject to changes. Later in the development cycle, schedulability analysis can be used to check the feasibility of the task set. However, the knowledge of the worst-case response times of tasks is often not sufficient to precisely determine the actions that would correct a non-schedulable design. In these situations, sensitivity analysis provides useful information for changing the implementation, by giving a measure of those computation times that must be reduced to achieve feasibility, or those that can be increased in case of a product extension, or providing the range of feasible periods for selecting the proper task activation rates. In this work, we exploit the concept of feasibility region to propose a faster and more concise solution to the sensitivity analysis problem with respect to existing techniques based on binary search. Furthermore, we show how the formalization of other problems in the feasibility domain, such as managing overloads through elastic scheduling, can be extended to the exact analysis. 1.

### Citations

2899 | Scheduling Algorithms for Multiprogramming in a Hard Real-Time Environment
- LIU, LAYLAND
- 1973
(Show Context)
Citation Context ...mputation times or on the activation rates to make the system schedulable. For models that can be analyzed by a simple utilizationbased test, the feasibility region is defined by the well known bound =-=[13]-=- C · f ≤ U A lub where UA lub is the least upper bound of the algorithm A considered for scheduling the set of tasks. As it will be shown later, the feasibility region both in the C-space and in the f... |

584 |
The rate monotonic scheduling algorithm: exact characterization andaverage case behavior
- Lehoczky, Sha, et al.
(Show Context)
Citation Context ...to the sensitivity problem have been provided in the domain of computation times. Early solutions to the sensitivity analysis problem can be traced back to the evaluation of the breakdown utilization =-=[12]-=-, where the critical scaling factor is computed for a fixed-priority scheduled system as the largest possible scaling value for task execution times still allowing the feasibility of the set. The appr... |

312 | Applying new scheduling theory to static priority pre-emptive scheduling
- Audsley, Burns, et al.
- 1993
(Show Context)
Citation Context .... Being a generalization of feasibility analysis, sensitivity analysis heavily borrows from existing results. The most popular among them is the Response Time Analysis (RTA) (Joseph and Pandya, 1986; =-=Audsley et al., 1993-=-). Although alternative efficient techniques have been proposed in the literature (Bini and Buttazzo, 2004), RTA is currently the most adopted technique for deciding upon the schedulability of a task ... |

268 |
Finding Response Times in a Real-Time System
- Joshep, Pandya
- 1986
(Show Context)
Citation Context ... a performance degradation. Being a generalization of feasibility analysis, sensitivity analysis heavily borrows from existing results. The most popular among them is the Response Time Analysis (RTA) =-=[11, 1]-=-. Although alternative efficient techniques have been proposed in the literature [4], RTA is currently the most adopted technique for deciding upon the schedulability of a task set, since it provides ... |

119 | An extendible approach for analysing fixed priority hard real-time systems
- Tindell
- 1994
(Show Context)
Citation Context ...hniques for sensitivity analysis are based on binary search over the schedulability property defined by Lehoczky [12], or other formulations of the algorithm for computing the response time of a task =-=[18, 23]-=-. In the context of distributed scheduling, a system-level sensitivity analysis of the task computation times against end-to-end deadlines has been proposed [19]. The method is based on binary search ... |

116 |
Schedulability analysis for tasks with static and dynamic offsets
- Palencia, Harbour
- 1998
(Show Context)
Citation Context ...ability of a task set, since it provides a necessary and sufficient condition. Efforts have been devoted to reduce its average complexity [21] and extend its applicability to more general task models =-=[17]-=-. Unfortunately, however, RTA is unfit for sensitivity analysis since it provides an aggregate value as the result of the application of a non invertible (and discontinuous) function to the task param... |

114 | A multiframe model for real-time tasks
- Mok, Chen
- 1996
(Show Context)
Citation Context ...me with a single attribute. Extensions of the model based on the triple (Ci, Ti, Di) have been proposed to add flexibility and reduce pessimism. For example, the multiframe task model proposed by Mok =-=[16]-=- allows the user to specify different execution times for different task instances, through a sequence of numbers. The generalized multi-frame task model [3] adds explicit deadlines to the multi-frame... |

66 | Generalized multiframe tasks
- Baruah, Chen, et al.
- 1999
(Show Context)
Citation Context ...the multiframe task model proposed by Mok [16] allows the user to specify different execution times for different task instances, through a sequence of numbers. The generalized multi-frame task model =-=[3]-=- adds explicit deadlines to the multi-frame model and allows assigning distinct minimum separation values to the instances inside a multi-frame cycle. The recurring task model defined by Baruah [2] al... |

65 | Elastic scheduling for flexible workload management
- BUTTAZZO, LIPARI, et al.
- 2002
(Show Context)
Citation Context ...ious work, our sensitivity analysis also applies to the domain of task periods, providing a theoretical support for those control systems that perform rate adaptation to cope with overload conditions =-=[7, 8]-=-. Moreover, it addresses very practical design issues, such as finding the fastest execution rate that can be assigned to one or more critical control loops. Alternatively, when fixing the defects of ... |

48 | Dynamic- and static-priority scheduling of recurring realtime tasks
- Baruah
(Show Context)
Citation Context ...el [3] adds explicit deadlines to the multi-frame model and allows assigning distinct minimum separation values to the instances inside a multi-frame cycle. The recurring task model defined by Baruah =-=[2]-=- allows modeling restricted forms of conditional real-time code and control flows. To relax the pessimistic assumptions typically made in the evaluation of the task set attributes, some authors [6, 14... |

45 | Schedulability analysis of periodic fixed priority systems
- Bini, Buttazzo
- 2004
(Show Context)
Citation Context ...analysis heavily borrows from existing results. The most popular among them is the Response Time Analysis (RTA) [11, 1]. Although alternative efficient techniques have been proposed in the literature =-=[4]-=-, RTA is currently the most adopted technique for deciding upon the schedulability of a task set, since it provides a necessary and sufficient condition. Efforts have been devoted to reduce its averag... |

43 | Vest: An aspect-based composition tool for real-time systems
- Stankovic, Zhu, et al.
- 2003
(Show Context)
Citation Context ...d reduce the time to market. Experiences on real-world applications show that design time validation of the schedulability properties can save over 50% of the time needed for the whole design process =-=[22]-=-, by simply pruning nonfeasible solutions from the design space. In many cases, however, the system is characterized by a high degree of heterogeneity and uncertainty, which makes the use of standard ... |

32 |
Task period selection and schedulability in real-time systems
- Seto, Lehoczky, et al.
- 1998
(Show Context)
Citation Context ...ion times C and the normalized deadlines are fixed. The formal definition of the feasibility region in the fspace can be conveniently derived from the schedulability condition provided by Seto et al. =-=[20]-=- and later explicitly formalized in [5]. Theorem 2 (from [20, 5]) A periodic task set T is schedulable under fixed priorities if and only if such ⎧ that: ⎪⎨ 0 ≤ fi ≤ ⎪⎩ ∀i = 1, . . .,N ni−1 − 1 Ci + n... |

23 |
Fixed-priority sensitivity analysis for linear compute time models
- Vestal
- 1994
(Show Context)
Citation Context ...r is computed for a fixed-priority scheduled system as the largest possible scaling value for task execution times still allowing the feasibility of the set. The approach was later extended by Vestal =-=[24]-=-, who addressed sensitivity analysis of fixed priority task sets by introducing slack variables in the exact feasibility equations defined in [12] and solving the corresponding equality conditions. Th... |

19 | Applying sensitivity analysis in real-time distributed systems
- Racu, Jersak, et al.
- 2005
(Show Context)
Citation Context ...puting the response time of a task [18, 23]. In the context of distributed scheduling, a system-level sensitivity analysis of the task computation times against end-to-end deadlines has been proposed =-=[19]-=-. The method is based on binary search and has been implemented in commercial tools by SymTAVision [10]. A problem of this method is that it performs a feasibility test at each iteration of the binary... |

18 | A probabilistic framework for schedulability analysis
- Burns, Bernat, et al.
(Show Context)
Citation Context ...ah [2] allows modeling restricted forms of conditional real-time code and control flows. To relax the pessimistic assumptions typically made in the evaluation of the task set attributes, some authors =-=[6, 14]-=- proposed a probabilistic model for task execution times and activations, which can be used to analyze soft real-time applications. Feasibility tests for these models are derived by applying stochasti... |

18 | Memory and time-efficient schedulability analysis of task sets with stochastic execution time
- MANOLACHE, ELES, et al.
- 2001
(Show Context)
Citation Context ...ah [2] allows modeling restricted forms of conditional real-time code and control flows. To relax the pessimistic assumptions typically made in the evaluation of the task set attributes, some authors =-=[6, 14]-=- proposed a probabilistic model for task execution times and activations, which can be used to analyze soft real-time applications. Feasibility tests for these models are derived by applying stochasti... |

17 | Improved response-time analysis calculations
- Sjödin, Hansson
- 1998
(Show Context)
Citation Context ...ently the most adopted technique for deciding upon the schedulability of a task set, since it provides a necessary and sufficient condition. Efforts have been devoted to reduce its average complexity =-=[21]-=- and extend its applicability to more general task models [17]. Unfortunately, however, RTA is unfit for sensitivity analysis since it provides an aggregate value as the result of the application of a... |

15 |
Sensitivity analysis of real-time task sets
- Punnekkat, Davis, et al.
- 1997
(Show Context)
Citation Context ...hniques for sensitivity analysis are based on binary search over the schedulability property defined by Lehoczky [12], or other formulations of the algorithm for computing the response time of a task =-=[18, 23]-=-. In the context of distributed scheduling, a system-level sensitivity analysis of the task computation times against end-to-end deadlines has been proposed [19]. The method is based on binary search ... |

11 | Optimal task rate selection in fixed priority systems
- Bini, Natale
- 2005
(Show Context)
Citation Context ...) and the analysis tool in MAST [15]. In this paper we present a new type of sensitivity analysis that exploits the concept of feasibility region in the domain of the task variables, as introduced in =-=[4, 5]-=-. By measuring the distance of a task configuration, expressed as a point in the space of the task variables, from the region delimiting the set of the feasible tasks, we can provide the variations th... |

10 | Managing quality-of-control performance under overload conditions
- Buttazzo, Velasco, et al.
- 2004
(Show Context)
Citation Context ...ious work, our sensitivity analysis also applies to the domain of task periods, providing a theoretical support for those control systems that perform rate adaptation to cope with overload conditions =-=[7, 8]-=-. Moreover, it addresses very practical design issues, such as finding the fastest execution rate that can be assigned to one or more critical control loops. Alternatively, when fixing the defects of ... |

3 |
SymTA/S symbolic timing analysis for systems. available at http://www.symta.org
- Hamann, Henia, et al.
- 2004
(Show Context)
Citation Context ...ensitivity analysis of the task computation times against end-to-end deadlines has been proposed [19]. The method is based on binary search and has been implemented in commercial tools by SymTAVision =-=[10]-=-. A problem of this method is that it performs a feasibility test at each iteration of the binary search, making the resulting complexity considerably high. Our algorithm does not suffer from this dra... |

3 |
MAST real-time view: A graphic UML tool for modeling object-oriented real-time systems
- Pasaje, Harbour, et al.
- 2001
(Show Context)
Citation Context ...is greater simplicity comes at the price of a simpler task model. Other tools offering a built-in sensitivity analysis engine are RTA-OSEK by ETAS (formerly LiveDevices) and the analysis tool in MAST =-=[15]-=-. In this paper we present a new type of sensitivity analysis that exploits the concept of feasibility region in the domain of the task variables, as introduced in [4, 5]. By measuring the distance of... |