Latency-Aware Generation of Single-Rate DAGs from Multi-Rate Task Sets

Modern automotive and avionics embedded systems
integrate several functionalities that are subject to complex timing requirements. A typical application in these fields is composed
of sensing, computation, and actuation. The ever increasing
complexity of heterogeneous sensors implies the adoption of
multi-rate task models scheduled onto parallel platforms. Aspects
like freshness of data or first reaction to an event are crucial
for the performance of the system. The Directed Acyclic Graph
(DAG) is a suitable model to express the complexity and the
parallelism of these tasks. However, deriving age and reaction
timing bounds is not trivial when DAG tasks have multiple rates.
In this paper, a method is proposed to convert a multi-rate
DAG task-set with timing constraints into a single-rate DAG that
optimizes schedulability, age and reaction latency, by inserting
suitable synchronization constructs. An experimental evaluation
is presented for an autonomous driving benchmark, validating
the proposed approach against state-of-the-art solutions