Fork-join model

How parallelism is expressed implicitly, as in an automatically parallelized DO loop, or explicitly, as in a UNIX fork-and-join model.- 39... 

This work considers a model where an Ada task is represented as a fork-join Directed Acyclic Graph (DAG) of potentially parallel code block instances (denoted as tasklets). The DAG of a task represents both the set of tasklets of the task, as well as the control-flow dependencies between the executions of the tasklets. 

This model of tasklet execution is a fully strict fork-join, where new tasklets spawned by the execution of a tasklet are required to complete execution before the spawning tasklet is allowed to complete Note that this model is mandatory for... 

A terminally strict fork join for implicit parallelization is left for future work. This is a model where a spawned tasklet is required to join with one ancestor, but not forcibly the parent. 

This model allows for the tasklet DAG to be converted (Figure 6) to a DAG of sub-tasks (Figure 6 middle) as commonly used in the real-time systems domain [16, 17, 18]. Response-time analysis techniques can also be used [19, 20] (restricted to non-nested tasklets), as the tasklet model is actually more restricted than the general real-time DAG model, as it considers a fuUy-strict fork-join, thus a synchronous model can be used [18] (Figure 6 right). 

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