Sample code for: Python 3.15 Preview: Upgraded JIT Compiler (#777)

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Co-authored-by: Bartosz Zaczyński <bartosz.zaczynski@gmail.com>

Author: 3 people

python315-jit-compiler/README.md

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+# Python 3.15 Preview: Upgraded JIT Compiler
+
+This folder provides the code examples for the Real Python tutorial [Python 3.15 Preview: Upgraded JIT Compiler](https://realpython.com/python315-jit-compiler/)

python315-jit-compiler/quick_bench.py

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+"""Quick benchmark: compare CPython 3.15 with the JIT off vs on.
+
+Run twice against the same 3.15 build and compare the two timings:
+
+    PYTHON_JIT=0 python quick_bench.py
+    PYTHON_JIT=1 python quick_bench.py
+"""
+
+import sys
+from timeit import timeit
+
+ITERATIONS = 20_000_000
+REPEATS = 5
+
+
+def workload():
+    x = 1.0
+    for _ in range(ITERATIONS):
+        x = x * 1.0001
+    return x
+
+
+def jit_enabled():
+    jit = getattr(sys, "_jit", None)
+    return bool(jit and jit.is_enabled())
+
+
+def main():
+    seconds = timeit(workload, number=REPEATS) / REPEATS
+    label = "JIT on" if jit_enabled() else "JIT off"
+    print(f"{label}: {seconds:.2f} s")
+
+
+if __name__ == "__main__":
+    main()