Independent Dual-Trajectory Redundant Execution: A Shared-Backend Mechanism for Soft-Error Detection

Soft-error detection in resource-constrained out-of-order processors requires balancing reliability against the cost of redundant execution. This paper proposes an independent dual-trajectory mechanism that preserves separate data-dependence chains while sharing physical backend resources, with error checking at selected architectural-event boundaries. Evaluation on SPECint2006 shows that redundant execution costs 18.3% geometric-mean IPC, versus 5.5% for a SHREC-like checker, along with higher protection-logic area. A 2400-injection campaign achieves an 86.4% conditional detection rate and a 78.5% reduction in adjudicated silent data corruption (SDC) relative to a detection-disabled baseline. A targeted ablation further demonstrates the benefit of independent value propagation, increasing detection from 8.7% to 84.3% compared with shared-source execution. These results quantify the reliability benefits of logical independence and its associated performance and hardware costs within a fixed-capacity out-of-order backend.