In Mobile Edge Computing (MEC), many tasks require specific service support for execution and in addition, have a dependent order of execution among the tasks. However, previous works often ignore the impact of having limited services cached at the edge nodes on (dependent) task offloading, thus may lead to an infeasible offloading decision or a longer completion time. To bridge the gap, this article studies how to efficiently offload dependent tasks to edge nodes with limited (and predetermined) service caching. We formally define the problem of offloading dependent tasks with service caching (ODT-SC), and prove that there exists no algorithm with constant approximation for this hard problem. Then, we design an efficient convex programming based algorithm (CP) to solve this problem. Moreover, we study a special case with a homogeneous MEC and propose a favorite successor based algorithm (FS) to solve this special case with a competitive ratio of $O(1)$ . Extensive simulation results using Google data traces show that our proposed algorithms can significantly reduce applications’ completion time by about 21-47 percent compared with other alternatives.

中文翻译：

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在移动边缘计算中使用依赖项和服务缓存卸载任务

在移动边缘计算 (MEC) 中，许多任务需要特定的服务支持才能执行，此外，任务之间具有相关的执行顺序。然而，以前的工作往往忽略在边缘节点缓存有限服务对（依赖）任务卸载的影响，从而可能导致不可行的卸载决策或更长的完成时间。为了弥补这一差距，本文研究了如何有效地将依赖任务卸载到具有有限（和预定）服务缓存的边缘节点。我们正式定义了使用服务缓存 (ODT-SC) 卸载依赖任务的问题，并证明对于这个难题不存在具有常数近似值的算法。然后，我们设计了一种高效的基于凸规划的算法（CP）来解决这个问题。而且，$O(1)$ . 使用 Google 数据跟踪的广泛模拟结果表明，与其他替代方案相比，我们提出的算法可以显着减少应用程序的完成时间约 21-47%。