System Introspection with Hardware Watchmachines

Unfortunately, current introspection mechanisms usually impose a high performance overhead or are difficult for programmers to use. For example, a 1000x slowdown using Valgrind for application debugging is not uncommon, and the lack of precise instruction counters has complicated research in deterministic multiprocessing [1, 7, 2]. However, with careful hardware support, introspection can be made both efficient and precise. One such example is the success of debug registers in x86 processors, which allow the system to efficiently monitor memory accesses, and trap to software precisely when a read or write occurs to a monitored address.