Dolos: Improving the Performance of Persistent Applications in ADR-Supported Secure Memory

The performance of persistent applications is severely hurt by current secure processor architectures. Persistent applications use long-latency flush instructions and memory fences to make sure that writes to persistent data reach the persistency domain in a way that is crash consistent. Recently introduced features like Intel’s Asynchronous DRAM Refresh (ADR) make the on-chip Write Pending Queue (WPQ) part of the persistency domain and help reduce the penalty of persisting data since data only needs to reach the on-chip WPQ to be considered persistent. However, when persistent applications run on secure processors, for the sake of securing memory many cycles are added to the critical path of their write operations before they ever reach the persistent WPQ, preventing them from fully exploiting the performance advantages of the persistent WPQ. Our goal in this work is to make it feasible for secure persistent applications to benefit more from the on-chip persistency domain.