Scheduling Persistent and Fully Cooperative Instructions

• Published in: 2021 IEEE 29th Annual International Symposium on Field-Programmable Custom Computing Machines (FCCM) p. 274
• Main Authors: Yang, Yu, Hemani, Ahmed, Paul, Kolin
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.05.2021
• Subjects: Automata; CGRA; Computer architecture; Constraint programming; Control systems; Instruction scheduling; Instruction sets; Processor scheduling; Schedules; Two level control; VLIW
• ISSN: 2576-2621
• DOI: 10.1109/FCCM51124.2021.00059

The distributed two-level control (D2LC) system has been adopted in streaming application accelerators that implement atomic vector operations. Each instruction of such architecture deals with one aspect (arithmetic, interconnect, storage, etc.) of an atomic vector operation. The D2LC architecture is different from traditional computer architecture such as MMX or VLIW. The D2LC architecture consists of many cells interconnected via a NoC. In each cell, there is a two-level controller. The level-1 controller sends instructions to configure their level-2 controllers. Each level-2 controller, once configured, works as an independent finite state machine (FSM). It manages a datapath for specific functionality, including computation, interconnection, as well as storage. We can say that the level-1 controllers implement threads while the level-2 controllers implement micro-threads. For generality, these microthreads, even though distributed in different cells, can be grouped by the interconnection units and orchestrated to implement a larger functionality. The compiler of D2LC architecture needs to schedule these micro-threads correctly so that the larger functionality is reached.