PipeCo: Pipelining Cold Start of Deep Learning Inference Services on Serverless Platforms

The fusion of serverless computing and deep learning (DL) has led to serverless inference, offering a promising approach for developing and deploying scalable and cost-efficient deep learning inference services (DLISs). However, the challenge of cold start presents a significant obstacle for DLISs, where DL model size greatly impacts latency. Existing studies mitigate cold starts by extending keep-alive times, which unfortunately leads to decreased resource utilization efficiency. To address this issue, we introduce PipeCo, a system designed to alleviate DLIS cold start. The core concept of PipeCo is to achieve the miniaturization and pipelining of DLIS cold start. Firstly, PipeCo utilizes a vertical partitioning approach to divide each DLIS into multiple slices, prewarming slices in a sequential and overlapping manner to decrease the overall cold-start latency. Secondly, PipeCo employs an attention-based prediction mechanism to estimate periodic patterns in requests and idle containers for scheduling slices. Thirdly, PipeCo incorporates a similarity-based container matcher for the reuse of idle containers. We implemented a prototype of PipeCo on the OpenFaaS platform and conducted extensive experiments using three real-world DLIS repositories. The results demonstrate that PipeCo effectively decreases end-to-end (E2E) latency by up to 62.67% on CPU and 58.81% on GPU clusters and reduces the overall resource usage by 65.31% compared to five state-of-the-art baselines.