Consistency Analysis of Reconfigurable Dataflow Specifications

Abstract

Abstract. Parameterized dataflow is a meta-modeling approach for incorporating dynamic reconfiguration capabilities into broad classes of dataflow-based design frameworks for digital signal processing (DSP). Through a novel formalization of dataflow parameterization, and a disciplined approach to specifying parameter reconfiguration, the parameterized dataflow framework provides for automated synthesis of robust and efficient embedded software. Central to these synthesis objectives is the formulation and analysis of consistency in parameterized dataflow specifications. Consistency analysis of reconfigurable specifications is particularly challenging due to their inherently dynamic behavior. This paper presents a novel framework, based on a concept of local synchrony, for managing consistency when synthesizing implementations from dynamicallyreconfigurable, parameterized dataflow graphs. Motivation and related workDataflow is an established computational model for simulation and synthesis of software for digital signal processing (DSP) applications. The modern trend toward highly dynamic and reconfigurable DSP system behavior, however, poses an important challenge for dataflow-based DSP modeling techniques, which have traditionally been well-suited primarily for applications with significantly static, high-level structure. Parameterized dataflow [1] is a promising new meta-modeling approach that addresses this challenge by systematically incorporating dynamic reconfiguration capabilities into broad classes of dataflow-based design frameworks for digital signal processing (DSP).Through a novel formalization of dataflow parameterization, and a disciplined approach to specifying parameter reconfiguration, the parameterized dataflow framework provides for automated synthesis of robust and efficient embedded software.

Buffer capacity computation for throughput-constrained modal task graphs

“…If there are two directed paths that connect a given pair of actors and that specify inconsistent relations between the execution rates of this pair of actors, then either for any finite number of initial tokens this subgraph will deadlock or there is an unbounded accumulation of tokens. Therefore, in order to verify whether there exists a bounded number of initial tokens that is sufficient to satisfy the throughput constraint, we need to check whether the relation between the execution rates of each pair of actors is strongly consistent [Bhattacharya and Bhattacharyya 2002;Lee 1991] over all paths between these two actors. We define strong consistency as the requirement that the constraints on execution rates are consistent for every valuation of the token transfer parameters.…”

Building a RTOS for MPSoC dataflow programming

“…In this paper, applications are described using parameterized dataflow modeling [7]. The chosen model of Parameterized Cyclo-Static Directed Acyclic Graph (PCSDAG) states that the graph can be totally reconfigured once before starting a new execution.…”

Buffer Capacity Computation for Throughput Constrained Streaming Applications with Data-Dependent Inter-Task Communication

“…If there are two directed paths that connect a given pair of actors and that specify inconsistent relations between the execution rates of this pair of actors, then either for any finite number of initial tokens this sub-graph will deadlock or there is an unbounded accumulation of tokens. Therefore, in order to verify whether there exists a bounded number of initial tokens that is sufficient to satisfy the throughput constraint, we need to check whether the relation between the execution rates of each pair of actors is strongly consistent [1,8] over all paths between these two actors. We define strong consistency as the requirement that the constraints on execution rates are consistent for every valuation of the token transfer parameters.…”

“…By construction of VRDF graphs, we have that if p falls into case (1), then there has to be an edge e ij ∈ E(v i )\E(p) that is on a simple directed path to v τ that transfers the value of p to another actor, and has constant token transfer quanta, i.e. the token production parameter of e ij falls into case (3).…”