# TC-NET-604 诊断：芯片 TX 分包粒度探测（= SET_TCP_MSS 有效值）
# 向回显端发送 N 字节，紧循环小包 recv + 计时，输出到达分块分布。
# 芯片 TX 包 = MSS 大小 → 到达粒度 ≈ 芯片发包大小（同交换机微秒级间隔，按 1ms 窗口聚合）。
import socket, sys, time

ip, port = sys.argv[1] if len(sys.argv) > 1 else "192.168.1.100", 8080
size = int(sys.argv[2]) if len(sys.argv) > 2 else 4096

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.settimeout(30)
s.connect((ip, int(port)))
payload = bytes(i & 0xFF for i in range(size))
t0 = time.perf_counter()
s.sendall(payload)

# 紧循环非阻塞式读取（recv 4096 上限，记录每次 recv 的字节数与相对时刻）
s.setblocking(False)
chunks = []
got = 0
deadline = time.time() + 10.0
while got < size and time.time() < deadline:
    try:
        b = s.recv(4096)
        if b:
            chunks.append((round((time.perf_counter() - t0) * 1000, 1), len(b)))
            got += len(b)
    except BlockingIOError:
        time.sleep(0.001)

s.close()
print(f"sent={size} got={got} in {round((time.perf_counter()-t0)*1000,1)}ms")
if chunks:
    from collections import Counter
    c = Counter(n for _, n in chunks)
    print("arrival chunks (ms, bytes):")
    for t, n in chunks:
        print(f"  +{t:7.1f}ms  {n:5d}B")
    print("size histogram:", dict(sorted(c.items())))
else:
    print("NO DATA (stall?)")