Performance Optimization of Serverless Computing for Latency-Guaranteed and Energy-Efficient Task Offloading in Energy-Harvesting Industrial IoT

Serverless architecture enables various intelligent applications to be run without managing infrastructure. In this architecture, the computing cost is generally proportional to the number of requested stateless functions and this number can affect the task completion time and, thus, it is prominent to decide an appropriate number of requested stateless functions. In this article, we propose a latency-guaranteed and energy-efficient task offloading (LETO) system where an Internet of Things (IoT) device decides the number of stateless functions requested to the cloud by considering the deadline on the task completion time and its energy level. To minimize the computing cost while guaranteeing sufficiently short task completion time and low energy outage probability, we formulate a constrained Markov decision process (CMDP) problem and convert the CMDP problem into an equivalent linear programming (LP) model. By solving the LP model, the optimal policy on the number of requested stateless functions can be achieved. Evaluation results illustrate that LETO can cut down the operating expenditure (OPEX) by up to 59% compared to a latency-guaranteed offloading scheme while keeping the task completion time and the energy outage probability below desirable levels.

I. Introduction

Recently, various intelligent applications requiring huge computing resource (e.g., industry automation, power systems automation, augmented reality (AR), and deep learning) have become more popular in the industrial Internet of Things (IoT) environment [1], [2]. However, IoT devices have limited battery capacities, which is a main implementation barrier of industrial IoT systems [3]. Therefore, industrial and academical researchers have interested on the energy harvesting technique where electricity is derived from external wasted energy [3]–[5]. However, the harvested energy is generally unmanageable and sporadic. Moreover, the energy can be harvested by spatiotemporal characteristics of the energy source.1 Therefore, it is a challenging problem to supply a sustainable energy to IoT devices. To alleviate this problem, many research have been conducted in [6]–[10]. Among them, the task offloading where an IoT device offloads its tasks for intelligent applications to an external cloud is a promising one.¹

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