Nexus: Transparent I/O Offloading for High-Density Serverless Computing
JooYoung Park, Kevin Nguetchouang, Jovan Stojkovic, Likun Zhang, Riccardo Mancini, Marco Cali, Dmitrii Ustiugov

TL;DR
Nexus is a hypervisor that decouples I/O from compute in serverless VMs, reducing resource use and latency while maintaining ecosystem compatibility.
Contribution
It introduces a transparent offloading mechanism that separates I/O processing from compute, improving efficiency without requiring code migration.
Findings
Reduces CPU and memory usage by up to 44% and 31%
Increases deployment density by 37%
Lowers latency by 39% (warm start) and 10% (cold start)
Abstract
Serverless computing relies on extreme multi-tenancy to remain economically viable, driving providers to rely on virtual machines (VMs) that ensure strong isolation and seamless ecosystem compatibility with the FaaS programming model. However, current architectures tightly couple application processing logic with I/O processing, forcing every VM to duplicate a heavy communication fabric (cloud SDK, RPC, and TCP/IP). Our analysis reveals this duplication consumes over 25% of a function's memory footprint, and may double the CPU cycles in VMs compared to bare-metal execution. While prior systems attempt to solve this using WebAssembly or library OSes, they naively sacrifice ecosystem compatibility, forcing developers to migrate code and dependencies to new languages. We introduce Nexus, a serverless-native KVM-based hypervisor that transparently decouples compute from I/O. Nexus shifts…
Peer Reviews
No public reviews on file for this paper yet. If you reviewed it on a platform where reviews are public (OpenReview, ICLR, NeurIPS, ICML), you can paste yours below so the community can read it here.
Videos
No videos yet. Explain this paper in a talk, walkthrough, or lecture? Add one.
