Quantification of ISA Impact on Superscalar Processing

The differences found between the superscalar performance in x86 and non-x86 processors and the peculiar characteristics of the x86 ISA recommend to carry out a thorough analysis of the available parallelism at the machine language layer. However, computer architecture evaluation requires new tools that complement the customary simulations and, in this sense, the traditional graph theory can help to create a new frame for fine-grain parallelism analysis. We construct the matrix representation associated to the data dependence graph of execution traces. In this paper, we explain how this matrix characterizes the corresponding code in a mathematical manner, fulfills a number of properties and restrictions, and provides information about the ability of the code to be processed concurrently. Besides, we also show how different data dependence sources can be composed, thus providing a mechanism to explore their final influence on the parallelism degree. These techniques are applied to an example from which some conclusions are derived