Edge computing has emerged as a popular paradigm for running latency-sensitive applications due to its ability to offer lower network latencies to end-users. In this paper, we argue that despite its lower network latency, the resource-constrained nature of the edge can result in higher end-to-end latency, especially at higher utilizations, when compared to cloud data centers. We study this edge performance inversion problem through an analytic comparison of edge and cloud latencies and analyze conditions under which the edge can yield worse performance than the cloud. To verify our analytic results, we conduct a detailed experimental comparison of the edge and the cloud latencies using a realistic application and real cloud workloads. Both our analytical and experimental results show that even at moderate utilizations, the edge queuing delays can offset the benefits of lower network latencies, and even result in performance inversion where running in the cloud would provide superior latencies. We finally discuss practical implications of our results and provide insights into how application designers and service providers should design edge applications and systems to avoid these pitfalls.

中文翻译：

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边缘的隐性成本：边缘和云延迟的性能比较

边缘计算已成为运行对延迟敏感的应用程序的流行范例，这是因为边缘计算能够为最终用户提供较低的网络延迟。在本文中，我们认为，尽管云延迟较低，但是资源受限的边缘特性可能会导致更高的端到端延迟，尤其是与云数据中心相比，利用率更高。我们通过对边缘与云延迟之间的分析比较来研究此边缘性能反演问题，并分析在哪些条件下边缘可能产生比云更差的性能。为了验证我们的分析结果，我们使用实际的应用程序和实际的云工作负载对边缘和云延迟进行了详细的实验比较。我们的分析和实验结果均表明，即使利用率适中，边缘排队延迟可以抵消较低网络等待时间的好处，甚至会导致性能反转，而在云中运行将提供更高的等待时间。最后，我们讨论了结果的实际含义，并提供了有关应用程序设计人员和服务提供商应如何设计边缘应用程序和系统以避免这些陷阱的见解。