Performance Benefits of Exploiting Control Independence

摘要

Many studies have shown that significant levels of parallelism can be extracted from ordinary programs if a processor can accurately look ahead arbitrarily far into the dynamic instruction stream. Control flow changes caused by conditional branches are a major impediment to determining which of the distant instructions belong to the dynamic instruction stream. This paper highlights the importance of exploiting control indepedence information for extracting this "distant parallelislm". We describe a methodology to find the maximum parallelism available when exploiting control independence. Our study with this tool shows that putting control independence to work has the potential to provide high performance.