Failure-atomic logging for persistent memory systems with cache-coherent fpgas

Abstract

Disclosed is a technique in which an application can record changes it makes to physical memory. In the technique, the application specifies a virtual memory region which is converted to a plurality of cache lines, each of which is monitored for changes by a device connected to a coherence interconnect coupled to the processor caches. The application sends a start signal to start the logging process and an end signal to stop the process. During the logging process, when a change occurs to one of the cache lines, an undo entry corresponding to the change is created and entered into a transaction log residing in persistent memory. The transaction log containing the undo entries makes the set of changes recorded in the transaction log atomic. If a failure occurs, the recorded changes can be undone as if they never occurred.