Software Logging under Speculative Parallelization

Speculative parallelization aggressively runs hardto -analyze codes in parallel. Speculative tasks generate unsafe state, which is typically buffered in caches. Often, a cache may have to buffer the state of several tasks and, as a result, it may have to hold multiple versions of the same variable. Modifying the cache to hold such multiple versions adds complexity and may increase the hit time. It is better to use logging, where the cache only stores the last versions of variables while the log keeps the older ones. Logging also helps to reduce the size of the speculative state to be retained in caches