LAUSR

As transistor scales down to sub-nanometer and processing cores with billions of transistors are integrated, reliable and energy-efficient Network-on-Chip (NoC) architectures are critical for improving performance of multicores. Near Threshold Voltage (NTV) scaling and approximate communication are popular techniques to reduce the energy consumption of NoC. Applications, which are insensitive to lower precision, can tolerate some loss in quality and take advantage of approximate communication. While approximate communication can improve energy-efficiency, these techniques are vulnerable to faults which in turn compromises reliability. In this article, we propose HREN: A Hybrid Reliable and Energy-efficient Network-on-Chip architecture that improves the reliability of NoC while utilizing both approximate communication and NTV scaling techniques in a multi-layered reliability model. HREN architecture facilitates two-levels of data approximation by identifying and compressing frequently repetitive patterns in the application data, thereby reducing the number of packet transmissions in NoC. As applications exhibit different traffic patterns in NoC, HREN switches the voltage mode of the network globally at runtime, thereby reducing the dynamic energy consumption while performing data approximation. HREN carefully monitors and handles the faults occurred due to NTV scaling and approximation while maintaining the fine balance between energy consumption and error rate. From our simulation results, HREN demonstrates up to 2.8x dynamic energy savings while reducing latency up to 2x. HREN shows an improvement of 4x to 5.5x in Energy-Delay Product over the baseline model for AxBench approximation benchmark suit on a 4 × 4 concentrated mesh (CMESH) architecture.