Task Scheduling for SoC-Based Dynamic SMP Clusters with Communication on the Fly

Abstract

The paper concerns program scheduling methods oriented towards "System on Chip" (SoC) -based modular parallel architectures with efficient features of interprocessor communication. In the assumed architecture, a global communication network connects many SoC modules in which SMP clusters are dynamically created at program run-time to provide transfers of shared data on the fly for many processors at a time. Programs are represented as extended macro data flow graphs, which adequately describe communication between processor data caches and shared memory modules. The proposed scheduling algorithm is composed of two phases. The first phase distributes program graph nodes among SoC modules, assuming full inter-processor connection networks. It is implemented as a genetic algorithm with internally embedded ETF heuristics. The second phase of the algorithm schedules computation and communication inside SoC modules, so as to optimally use dynamic processor switching between clusters and data read on the fly mechanisms. Scheduling results of sample program graphs evaluated using simulation methods illustrate the efficiency of the proposed algorithm.

Multi-CMP system with data communication on the fly

“…EMDFGs can be generated manually by programmers but it is complicated and error prone. What we recommend is that EMDFGs are generated automatically by a scheduling program [14,15] whose input is a program MDFG and which takes into account the parameters of the target system with the proposed architecture. A scheduled EMDFG will be then transformed into an executive code in which special instructions, representing the described above special elements of the extended graph, will be automatically inserted.…”

“…The core switching and communication on the fly can be automatically embedded in the application program code by special scheduling algorithms [14,15] in a way, which corresponds to particular program needs. In this respect, the applied communication method shows features of dynamically reconfigurable embedded system, in which internal structures of CMP modules are adjusted to program requirements.…”