Pub Date : 1995-12-05DOI: 10.1109/REAL.1995.495206
T. Abdelzaher, K. Shin
In this paper we present a branch-and-bound (B&B) algorithm for combined task and message scheduling in distributed hard real-time systems. The algorithm finds an optimal schedule for a set of communicating tasks with known arrival times, precedence constraints, and resource requirements in conjunction with the assignment and scheduling of intertask messages over communication links. The schedule is "optimal" in the sense of minimizing maximum task lateness under a heuristic message priority assignment found during the search. A robotics application is used to illustrate the utility and potential of the algorithm. Results of an extensive simulation study analyzing its performance are also presented.
{"title":"Optimal combined task and message scheduling in distributed real-time systems","authors":"T. Abdelzaher, K. Shin","doi":"10.1109/REAL.1995.495206","DOIUrl":"https://doi.org/10.1109/REAL.1995.495206","url":null,"abstract":"In this paper we present a branch-and-bound (B&B) algorithm for combined task and message scheduling in distributed hard real-time systems. The algorithm finds an optimal schedule for a set of communicating tasks with known arrival times, precedence constraints, and resource requirements in conjunction with the assignment and scheduling of intertask messages over communication links. The schedule is \"optimal\" in the sense of minimizing maximum task lateness under a heuristic message priority assignment found during the search. A robotics application is used to illustrate the utility and potential of the algorithm. Results of an extensive simulation study analyzing its performance are also presented.","PeriodicalId":231426,"journal":{"name":"Proceedings 16th IEEE Real-Time Systems Symposium","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130969463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-12-05DOI: 10.1109/REAL.1995.495220
Y. Hur, Young Hyun Bae, Sung-Soo Lim, Sung-Kwan Kim, Byung-Do Rhee, S. Min, C. Park, Heonshik Shin, Chong-Sang Kim
This paper presents a case study of worst case timing analysis for a RISC processor. The target machine consists of the R3000 CPU and R3010 FPA (Floating Point Accelerator). This target machine is typical of a RISC system with pipelined execution units and cache memories. Our methodology is an extension of the existing timing schema. The extended timing schema provides means to reason about the execution time variation of a program construct by surrounding program constructs due to pipelined execution and cache memories of RISC processors. The main focus of this paper is on explaining the necessary steps for performing timing analysis of a given target machine within the extended timing schema framework. This paper also gives results from experiments using a timing tool for the target machine that is built based on the extended timing schema approach.
{"title":"Worst case timing analysis of RISC processors: R3000/R3010 case study","authors":"Y. Hur, Young Hyun Bae, Sung-Soo Lim, Sung-Kwan Kim, Byung-Do Rhee, S. Min, C. Park, Heonshik Shin, Chong-Sang Kim","doi":"10.1109/REAL.1995.495220","DOIUrl":"https://doi.org/10.1109/REAL.1995.495220","url":null,"abstract":"This paper presents a case study of worst case timing analysis for a RISC processor. The target machine consists of the R3000 CPU and R3010 FPA (Floating Point Accelerator). This target machine is typical of a RISC system with pipelined execution units and cache memories. Our methodology is an extension of the existing timing schema. The extended timing schema provides means to reason about the execution time variation of a program construct by surrounding program constructs due to pipelined execution and cache memories of RISC processors. The main focus of this paper is on explaining the necessary steps for performing timing analysis of a given target machine within the extended timing schema framework. This paper also gives results from experiments using a timing tool for the target machine that is built based on the extended timing schema approach.","PeriodicalId":231426,"journal":{"name":"Proceedings 16th IEEE Real-Time Systems Symposium","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133486889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-12-05DOI: 10.1109/REAL.1995.495205
G. Fohler
In this paper we present algorithms for the joint scheduling of periodic and aperiodic tasks in statically scheduled distributed real-time systems. Periodic tasks are precedence constrained, distributed, and communicating over the nodes of the systems. Both soft and hard aperiodic tasks are handled. After a static schedule has been created in a first step, the algorithms determine the amount and distribution of unused resources and leeway in it. These are then used to incorporate aperiodic tasks into the schedule by shifting the periodic tasks' execution, without violating their feasibility. Run-time mechanisms are simple and require only little memory. Processors and communication nodes can be utilized fully. The algorithm performs on optimal online guarantee algorithm for hard aperiodic tasks of O(N). An extensive simulation study exhibits very high guarantee ratios for various load and deadline scenarios, which underlines the efficiency of our method.
{"title":"Joint scheduling of distributed complex periodic and hard aperiodic tasks in statically scheduled systems","authors":"G. Fohler","doi":"10.1109/REAL.1995.495205","DOIUrl":"https://doi.org/10.1109/REAL.1995.495205","url":null,"abstract":"In this paper we present algorithms for the joint scheduling of periodic and aperiodic tasks in statically scheduled distributed real-time systems. Periodic tasks are precedence constrained, distributed, and communicating over the nodes of the systems. Both soft and hard aperiodic tasks are handled. After a static schedule has been created in a first step, the algorithms determine the amount and distribution of unused resources and leeway in it. These are then used to incorporate aperiodic tasks into the schedule by shifting the periodic tasks' execution, without violating their feasibility. Run-time mechanisms are simple and require only little memory. Processors and communication nodes can be utilized fully. The algorithm performs on optimal online guarantee algorithm for hard aperiodic tasks of O(N). An extensive simulation study exhibits very high guarantee ratios for various load and deadline scenarios, which underlines the efficiency of our method.","PeriodicalId":231426,"journal":{"name":"Proceedings 16th IEEE Real-Time Systems Symposium","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131779326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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