Simon Willison’s Weblog

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17th March 2026

Great news—we’ve hit our (very modest) performance goals for the CPython JIT over a year early for macOS AArch64, and a few months early for x86_64 Linux. The 3.15 alpha JIT is about 11-12% faster on macOS AArch64 than the tail calling interpreter, and 5-6%faster than the standard interpreter on x86_64 Linux.

Ken Jin, Python 3.15’s JIT is now back on track

This is a quotation collected by Simon Willison, posted on 17th March 2026.