LogCA: A Performance Model for Hardware Accelerators

To address the Dark Silicon problem, architects have increasingly turned to special-purpose hardware accelerators to improve the performance and energy efficiency of common computational kernels, such as encryption and compression. Unfortunately, the latency and overhead required to off-load a computation to an accelerator sometimes outweighs the potential benefits, resulting in a net decrease in performance or energy efficiency. To help architects and programmers reason about these trade-offs, we have developed the LogCA model, a simple performance model for hardware accelerators. LogCA provides a simplified abstraction of a hardware accelerator characterized by five key parameters. We have validated the model against a variety of accelerators, ranging from on-chip cryptographic accelerators in Sun's UltraSparc T2 and Intel's Sandy Bridge to both discrete and integrated GPUs.