Sentinel Scheduling for VLIW and Superscalar Processors

Speculative execution is an important source of parallelism for VLIW and superscalar processors. A serious challenge with compiler-controlled speculative execution is to accurately detect and report all program execution errors at the time of occurrence. In this paper, a set of architectural features and compile-time scheduling support referred to as sentinel scheduling is introduced. Sentinel scheduling provides an effective framework for compiler-controlled speculative execution that accurately detects and reports all exceptions. Sentinel scheduling also supports speculative execution of store instructions by providing a store buffer which allows probationary entries. Experimental results show that sentinel scheduling is highly effective for a wide range of VLIW and superscalar processors.