QUICK: A flexible full-system functional model

In this paper, we introduce the concept of full-system complete-and-rollback functional simulators that make efficient functional models in functional/timing partitioned simulators. Complete-and-rollback functional simulators can efficiently drive simulators of resolutions ranging from functional-only to cycle-accurate for a wide range of simulated machines. Complete-and-rollback functional models achieve their capabilities by executing instructions to completion, enabling their execution to be highly optimized, but providing rollback capabilities to enable on-the-fly modifications to the functional execution. We also introduce QUICK, an implementation of a full-system complete-and-rollback functional model that supports the x86 and PowerPC ISAs, boots unmodified Windows XP and Linux, and runs unmodified applications such as YouTube on Internet Explorer while fully supporting rollbacks, including across I/O operations. We present various case studies using QUICK and conduct performance analyses to demonstrate its simulation performance.