2026-07-15 –, Auditorium Hall (S1)
This talk is a follow-up to my EuroPython 2025 session on the foundations of the CPython JIT compiler. It looks at how the JIT has evolved since Python 3.14 and where it stands as Python 3.15 approaches release. We cover the transition of the JIT from an experimental feature towards a supported part of CPython, how it fits into the runtime today, and what that means in practice for users and distributors. The talk also explores how the JIT interacts with free-threaded builds, the current status of integration with external debuggers, and how these constraints shape real-world usage. Finally, we examine how the JIT performs today, where it already delivers substantial speedups, where it does not, and what realistic performance expectations look like for Python 3.15.
Diego Russo is a CPython core developer and Principal Software Engineer in Arm’s Runtimes team, based in Cambridge, UK. He has been using Python since 2006 and contributing to CPython since 2023, with a focus on interpreter performance, JIT-related work, CI infrastructure, and ensuring CPython and its ecosystem run reliably and efficiently on Arm platforms. His work sits at the intersection of runtime, performance engineering, and large-scale open source collaboration.
Diego is also a EuroPython organiser and leads the Arm Python Guild, an internal community of more than 1,400 Python developers working across the company.