In this paper we present a new formal model, called p-FSM, for system-level power management design. The p-FSM is a modular, compositional, hierarchical, and unified model for hardware and software components. The model encapsulates power management control mechanisms, operating states and properties of a component that affect power, energy and thermal aspects of the system. Inter-component dependencies are modeled through a component-based interface. By connecting multiple p-FSMs we gradually compose the model of the whole system which ensures correct-by-construction system-level control sequencing. The model can also be used to formally verify the functional correctness of the power management design.

Historically, hardware acceleration technologies have either been application-specific, therefore lacking in flexibility, or fully programmable, thereby suffering from notable inefficiencies on an application-by-application basis. To address the growing need for domain-specific acceleration technologies, this paper describes a design methodology (i) to automatically generate a domain-specific coarse-grained array from a set of representative applications and (ii) to introduce limited forms of architectural generality to increase the likelihood that additional applications can be successfully mapped onto it. In particular, coarse-grained arrays generated using our approach are intended to be integrated into customizable processors that use application-specific instruction set extensions to accelerate performance and reduce energy; rather than implementing these extensions using application-specific integrated circuit (ASIC) logic, which lacks flexibility, they can be synthesized onto our reconfigurable array instead, allowing the processor to be used for a variety of applications in related domains. Results show that our array is around 2× slower and 15× larger than an ultimately efficient ASIC implementation, and thus far more efficient than fieldprogrammable gate arrays (FPGAs), which are known to be 3-4× slower and 20-40× larger. Additionally, we estimate that our array is usually around 2× larger and 2× slower than an accelerator synthesized using traditional datapath merging, which has, if any, very limited flexibility beyond the design set of DFGs.

Hardware specialization is often the key to efficiency for programmable embedded systems, but comes at the expense of flexibility. This paper combines flexibility and efficiency in the design and synthesis of domain-specific datapaths. We merge all individual paths from the Data Flow Graphs (DFGs) of the target applications, leading to a minimal set of required resources; this set is organized into a column of physical operators and cloned, thus generating a domain-specific rectangular lattice. A bus-based FPGA-style interconnection network is then generated and dimensioned to meet the needs of the applications. Our results demonstrate that the lattice has good flexibility: DFGs that were not used as part of the datapath creation phase can be mapped onto it with high probability. Compared to an ASIC design of a single DFG, the speed of our domain-specific coarse-grained reconfigurable datapath is degraded by a factor up to 2×, compared to 3-4× for an FPGA; similarly, our lattice is up to 10× larger than an ASIC, compared to 20-40× for an FPGA. We estimate that our array is up to 6× larger than an ASIC accelerator, which is synthesized using datapath merging and has limited or null generality.