Before revision:  However, we find that a direct application of G-thinker is insufficient due to the drastically different running time of different tasks that violates the original design assumption of G-thinker , requiring a system URLe.
After revision:  However, we find that a direct application of G-thinker results in the straggler problem due to (i) the drastic load imbalance among different tasks and (ii) the difficulty of predicting the task running time and the time growth with task-subgraph size. We address these challenges by redesigning G-thinker , requiring a system URLe.