This dataset supports the article entitled "Machine Learning for Run-Time Energy Optimisation in Many-Core Systems" accepted for publication in DATE 2017 Data Supporting Figures: Fig. 3 - Workload misprediction for MPEG4 and learning impact on average slack. Table I - COMPARATIVE EVALUATION OF NORMALISED ENERGY AND PERFORMANCE REQUIREMENTS Table II - COMPARATIVE EVALUATION OF THE NUMBER OF EXPLORATIONS Table III - COMPARATIVE EVALUATION OF WORST CASE LEARNING OVERHEAD