Unpacking Cloudflare Workers CPU Performance Benchmarks

This post details the investigation and resolution of performance disparities in Cloudflare Workers benchmarks compared to Vercel. Key contributions include: 1. Updating the scheduling algorithm to better handle CPU-bound workloads by spinning up new isolates faster, ensuring that billing accurately reflects CPU time and not scheduling delays. 2. Tuning the V8 garbage collector by allowing more dynamic young generation sizing, leading to an approximate 25% performance boost for benchmarks and other Workers. 3. Optimizing the OpenNext adapter for Next.js by reducing unnecessary data buffer copies and improving stream handling, addressing a significant portion of the remaining performance gap.