History

1.2.0 (2026-08-24)

New feature: CPU stack sampling — a watchdog daemon thread samples the loop thread's stack during CPU-bound slices, attaching aggregated stacks with counts to SlowTaskEvent.cpu_stack_samples, so cpu_blocking events carry attribution like IO events do
On by default: detect_slow_tasks() starts it automatically (cpu_sampling=False to opt out); start_cpu_sampling() called beforehand customizes it
Derived defaults: arming delay follows half the slow-task threshold; idle wake-up follows min(50ms, max(arm, interval)) with a 1ms sleep floor, so no configuration can busy-loop the watchdog
Samples the thread that published the slice — event loops running outside the main thread are attributed correctly
Fork-safe: forked children (e.g. gunicorn --preload workers) restart the watchdog via os.register_at_fork
aiocop's own frames are excluded from samples via a package-path prefix match

Fix time.sleep being double-counted on Python 3.13+, which emits a native audit event for it (#11, #12)
Make patch_audit_functions() and start_blocking_io_detection() idempotent — repeat calls now warn and no-op instead of silently double-counting events (#9, #10)

Capture context both before and after callback execution, merging non-None post values over pre values to handle spans set lazily