Function-Level Processor (FLP): Raising efficiency by operating at function granularity for market-oriented MPSoC

The exponential growth in computation demand drives chip vendors to heterogeneous architectures combining Instruction-Level Processors (ILPs) and custom HW Accelerators (HWACCs) in an attempt to provide the needed processing capabilities while meeting power/energy requirements. ILPs, on one hand, are highly flexible, but power inefficient. Custom HWACCs, on the other hand, are inflexible (focusing on dedicated kernels), but highly power efficient. Since, designing HWACCs for every application is cost prohibitive, large portions of applications still run inefficiently on ILPs. New processing architectures are needed that combine the power efficiency of HWACCs while still retaining sufficient flexibility to realize applications across targeted market segments. This paper introduces Function-Level Processors (FLPs) to fill the gap between ILPs and dedicated HWACCs. FLPs are comprised of configurable Function Blocks (FBs) implementing selected functions which are then interconnected via programmable point-to-point connections constructing an extensible/configurable macro data-path. An FLP raises programming abstraction to a Function-Set Architecture (FSA) controlling FBs allocation, configuration and scheduling. We demonstrate FLP benefits with an industry example of the Pipeline-Vision Processor (PVP). We highlight the gained flexibility by mapping 10 embedded vision applications entirely to the FLP-PVP offering up to 22.4 GOPs/s with average power of 120 mW. The results also demonstrate that our FLP-PVP solution consumes 14×-18× less power than an ILP and 5x less power than a hybrid ILP+HWACCs solution.