Efficient Run-time Monitoring Of Timing Constraints

Author(s):  
A.K. Mok ◽  
Guangtian Liu
Keyword(s):  
Author(s):  
Jia Xu

Utilizing non-zero offsets when scheduling real-time periodic processes significantly increases the chances of satisfying all the timing constraints in a real-time system. In this paper, a method that enables the utilization of non-zero offsets in the pre-run-time scheduling of asynchronous and periodic processes with release times, deadlines, precedence and exclusion relations on either a uniprocessor or on a multiprocessor in real-time embedded systems is presented. This paper also identifies for the first time, the set of general conditions that a periodic process newpi with release time rnewpi, computation time cnewpi, deadline dnewpi, period prdnewpi, permitted range of offset onewpi, must satisfy, in order to satisfy the timing constraints of any given asynchronous process ai with computation time cai, deadline dai, minimum time between two consecutive requests minai, and earliest time that asynchronous process ai can make a request for execution lai. A method based on these general conditions for converting asynchronous processes with earliest request times into new periodic processes with offset constraints is also introduced.


10.28945/3391 ◽  
2009 ◽  
Author(s):  
Moshe Pelleh

In our world, where most systems become embedded systems, the approach of designing embedded systems is still frequently similar to the approach of designing organic systems (or not embedded systems). An organic system, like a personal computer or a work station, must be able to run any task submitted to it at any time (with certain constrains depending on the machine). Consequently, it must have a sophisticated general purpose Operating System (OS) to schedule, dispatch, maintain and monitor the tasks and assist them in special cases (particularly communication and synchronization between them and with external devices). These OSs require an overhead on the memory, on the cache and on the run time. Moreover, generally they are task oriented rather than machine oriented; therefore the processor's throughput is penalized. On the other hand, an embedded system, like an Anti-lock Braking System (ABS), executes always the same software application. Frequently it is a small or medium size system, or made up of several such systems. Many small or medium size embedded systems, with limited number of tasks, can be scheduled by our proposed hardware architecture, based on the Motorola 500MHz MPC7410 processor, enhancing its throughput and avoiding the software OS overhead, complexity, maintenance and price. Encouraged by our experimental results, we shall develop a compiler to assist our method. In the meantime we will present here our proposal and the experimental results.


2014 ◽  
Vol 24 (12) ◽  
pp. 2767-2781
Author(s):  
Hao SUN ◽  
Hui-Peng LI ◽  
Qing-Kai ZENG
Keyword(s):  

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