An apparatus and method for determining thread execution parallelism. For example, a processor in accordance with one embodiment comprises: a plurality of cores to execute a plurality of threads; a plurality of counters to collect data related to the execution of the plurality of threads on the plurality of cores; a dependency analysis module to analyze the data related to the execution of the threads and responsively determine a level of inter-thread dependency; and a control module to responsively adjust operation of the plurality of cores based on the determined level of inter-thread dependency.