relOBI: A Reliable Low-latency Interconnect for Tightly-Coupled On-chip Communication

TL;DR

relOBI is a new on-chip interconnect extension that enhances reliability in radiation-heavy environments by combining TMR and ECC, significantly reducing fault vulnerability with moderate area overhead.

Contribution

This work introduces relOBI, a reliable low-latency interconnect that integrates TMR and ECC, offering improved fault tolerance over existing solutions.

Findings

Fault vulnerability reduced from 34.85% to 0%

Area overhead is 2.6 times higher than baseline

Area overhead is 1.8 times lower than similar solutions

Abstract

On-chip communication is a critical element of modern systems-on-chip (SoCs), allowing processor cores to interact with memory and peripherals. Interconnects require special care in radiation-heavy environments, as any soft error within the SoC interconnect is likely to cause a functional failure of the whole SoC. This work proposes relOBI, an extension to the Open Bus Interface (OBI) combining triple modular redundancy (TMR) for critical handshake signals with error correction codes (ECC) protection on other signals. Implementing and testing the reliable crossbar shows improved reliability to injected single faults from a vulnerability of 34.85 % to zero compared to the irredundant baseline, with an area increase of 2.6 $\times$. The area overhead is 1.8 $\times$ lower than that reported in the literature for fine-grained triplication and voting.