"""At what interval does ri_energy_nj actually advance under continuous load?

The crate's own liveness criterion: a rail is live when it advanced in >=80% of
sampled intervals. Applied here to find the shortest interval that clears it,
which is the counter's declarable update period.
"""
import ctypes, os, time, statistics
_l = ctypes.CDLL("/usr/lib/libSystem.B.dylib"); _b = ctypes.create_string_buffer(464); _p = os.getpid()
def nj():
    _l.proc_pid_rusage(ctypes.c_int(_p), ctypes.c_int(6), ctypes.byref(_b))
    return int.from_bytes(_b.raw[336:344], "little")

def trial(interval_s, n=60):
    """Burn for `interval_s` per sample; report the fraction that advanced."""
    adv = 0; deltas = []
    prev = nj()
    for _ in range(n):
        t_end = time.perf_counter() + interval_s
        x = 0
        while time.perf_counter() < t_end:
            x += 1                      # burn this thread's CPU
        cur = nj()
        if cur > prev: adv += 1
        deltas.append(cur - prev)
        prev = cur
    nz = [d for d in deltas if d > 0]
    return adv / n, (statistics.median(nz)/1e3 if nz else 0.0)

print(f"{'interval':>10}  {'advanced':>9}  {'median ΔµJ':>11}  live(>=80%)")
for us in (10, 50, 100, 250, 500, 1_000, 2_000, 5_000, 10_000, 20_000, 50_000):
    frac, med = trial(us/1e6)
    print(f"{us:>8}µs  {frac*100:>8.0f}%  {med:>11.1f}  {'yes' if frac >= 0.80 else 'no'}")