Python 3.15 adds profiling.sampling (Tachyon): a zero-overhead statistical profiler that attaches to live processes without code changes.
Key Takeaways
Tachyon reads call stacks from external process memory at configurable rates (default ~10 kHz), estimating time via sample counts times interval.
attach and dump subcommands work on running PIDs with no restart required; dump is useful for hung/unresponsive processes.
Output formats include flame graphs (HTML), gecko JSON for Firefox Profiler, line-by-line heatmaps, and opcode-level bytecode views.
Not suited for sub-second scripts, exact call counts, or sub-2% micro-benchmark comparisons; use profiling.tracing or timeit there.
Production guidelines: profile under representative load, start with 10-30s windows, and note that the profiler consumes CPU on the observer machine, not the target.
Hacker News Comment Review
The sole comment reflects that a stdlib statistical profiler was long expected to require a third-party tool; shipping it in 3.15 is seen as a meaningful batteries-included win.
