Neural Acceleration for GPU Throughput Processors

Graphics Processing Units (GPUs) can accelerate diverse classes of applications, such as recognition, gaming, data analytics, weather prediction, and multimedia. Many of these applications are amenable to approximate execution. This application characteristic provides an opportunity to improve GPU performance and efficiency. Among approximation techniques, neural accelerators have been shown to provide significant performance and efficiency gains when augmenting CPU processors. However, the integration of neural accelerators within a GPU processor has remained unexplored. GPUs are, in a sense, many-core accelerators that exploit large degrees of data-level parallelism in the applications through the SIMT execution model. This paper aims to harmoniously bring neural and GPU accelerators together without hindering SIMT execution or adding excessive hardware overhead. We introduce a low overhead neurally accelerated architecture for GPUs, called NGPU, that enables scalable integration of neural accelerators for large number of GPU cores. This work also devises a mechanism that controls the tradeoff between the quality of results and the benefits from neural acceleration. Compared to the baseline GPU architecture, cycle-accurate simulation results for NGPU show a 2.4x average speedup and a 2.8x average energy reduction within 10% quality loss margin across a diverse set of benchmarks. The proposed quality control mechanism retains a 1.9x average speedup and a 2.1x energy reduction while reducing the degradation in the quality of results to 2.5%. These benefits are achieved by less than 1% area overhead.