Python 3.15's JIT is now back on track

The CPython JIT compiler has exceeded its performance goals ahead of schedule, achieving 11-12% speedup on macOS AArch64 and 5-6% on x86_64 Linux compared to the interpreter in Python 3.15 alpha. After the Faster CPython team lost its main sponsor in 2025, the project shifted to community stewardship, and a small group of core contributors—through a combination of strategic planning and fortunate timing—revived the JIT from near-stagnation in 3.13/3.14 to meaningful performance gains.