Exploiting Thread-Level Parallelism to Build Decision Trees

Classification is an important data mining task, and decision trees have emerged as a popular classifier due to their simplicity and relatively low computational complexity. However, as datasets get extremely large, the time required to build a decision tree still becomes intractable. Hence, there is an increasing need for more efficient tree-building algorithms. One approach to this problem involves using a parallel mode of computation. Prior work has successfully used processor-level parallelism to partition the data and computation. We propose to use Cray’s Multi-Threaded Architecture (MTA) and extend the idea by employing thread-level parallelism to reduce the execution time of the tree building process. Decision tree building is well-suited for such low-level parallelism as it requires a large number of independent computations. In this paper, we present the analysis and parallel implementation of the ID3 algorithm, along with experimental results.