Hyperperiod is the least-common multiple of the periods of all the processes. 11. Jitter Jitter { Delay between time task was ready & when it starts executing Causes: Other tasks executing/ready hyperperiod H major cycle. divisors, the hyperperiod can be a large value. For the above mentioned reasons, a task set with a small hyperperiod is a desirable feature. CPSC-663: Real-Time Systems Clock-Driven Scheduling 2 Frame Size Constraints •Frames must be sufﬁciently long so that every job can start and complete within a single frame: •The hyperperiod must have an integer number of frames: In this paper, we propose a model where each selected period is not restricted to be a natural number, but can be any rational number within a range. The following is a possible cyclic schedule. Only f = 2 satisfies the third constraint. The hyperperiod represents then the maximum time interval between two successive completions of executions of computation (and not requests). In fact, as shown in [6], the hyperperiod grows exponentially with the greatest period and with the number of tasks. 0 4 8 12 16 20 T 1 T 1 T 1 T 1 T 1 T 3 T 2 T 2 T 2 T 2 T 4 schedule repeats 10 Real-Time Systems Jitter Jitter { Delay between time task was ready & when it starts executing Causes: Other tasks executing/ready hyperperiod { LCM of the task’s periods During the hyperperiod, the tasks will line up to execute at same time Thus, utilization during hyperperiod is the same as if they have the same period 49. The hyperperiod represents then the maximum time interval between two successive completions of executions of computation (and not requests). It is a finite period that covers all possible combinations of process executions. Task period selection is often used to adjust the workload to the available computational resources. In this paper, we propose a model where each selected period is not restricted to be a natural number, but can be any rational number within a range. • The hyperperiod must have an integer number of frames: • For monitoring purposes, frames must be sufﬁciently small that between release time and deadline of every job there is at least one frame: (1)f≥max(e i) (2)fH(f"divides"H) ii i i fpfD ttpf Task period selection is often used to adjust the workload to the available computational resources. We list all the multiples … The most com-mon technique is to select task periods to be harmonic, So if you have a task set of T1 with a period 3, T2 with a period 4, and T3 with a period 10, then we calculate the following. hyperperiod { LCM of the task’s periods During the hyperperiod, the tasks will line up to execute at same time Thus, utilization during hyperperiod is the same as if they have the same period 49. Hyperperiod is 20, so by second constraint, possible choices for f are 2, 4, 5, 10, and 20. The definition of the hyperperiod is calculated as the least common multiple of the individual periods of all the tasks.