This paper discusses Meta’s internal system for serverless computing called XFaaS. XFaaS allows engineers to run code without the need for dedicated servers and offers hyperscale and low-cost serverless functions. The paper explores the challenges faced in building this system, such as handling load spikes, ensuring fast function startup and execution, global load balancing, and preventing overload of downstream services. The architecture of XFaaS consists of five main components and incorporates performance optimizations such as time-shifted computing and cooperative JIT compilation. The paper evaluates the system’s ability to achieve high utilization, efficient execution of functions, and prevent overload. While XFaaS is unique in characterizing a serverless system at scale, it has different design choices and constraints compared to public cloud providers. The paper raises questions about the suitability of certain functions for XFaaS and the source of anecdotal knowledge regarding higher utilization.
https://www.micahlerner.com/2024/01/23/xfaas-hyperscale-and-low-cost-serverless-functions-at-meta.html