Python 串行接收数据包的速率低于发送数据包的速率

Question

我设置了一个测试，将两个 uart-to-usb 适配器连接在一起。我以 100 Hz 左右的速率发送 14 字节数据包。不过，接收线程似乎只能在 60 Hz 左右运行。我已经使用逻辑分析仪验证了数据以正确的速率发送。

我一直在研究这个问题，下面有一个非常简化的测试代码，它只检查serial.in_waiting 的值更改。这是为了消除任何其他可能占用我时间的过程。

我的测试代码：

port1 = 'COM3'  
port2 = 'COM4'  
baud_rate = 115200
packet_size = 14  # Size of each packet in bytes
packet_interval = 0.01  # Interval between packets in seconds (10 ms)
number_of_packets = 100
# Generate test data to send in each packet
test_packet = b'ABCDEFGHIJKLMNOPQRSTUVWXYZ'[:packet_size]

def sender():
    with serial.Serial(port1, baud_rate, timeout=1) as ser:
        start_time = 0
        for _ in range(number_of_packets):
            ser.write(test_packet)
            ser.flush()
            time_taken = time.perf_counter() - start_time
            print(f"Sent {len(test_packet)} bytes in {time_taken:.6f} seconds. {1/time_taken:0.6f} Hz")

            start_time = time.perf_counter()
            # sleep_time = max(packet_interval-time_taken, 0)
            time.sleep(packet_interval)

def receiver():
    with serial.Serial(port2, baud_rate, timeout=1) as ser:
        ser.reset_input_buffer()
        received_data = b''
        start_time = time.perf_counter()
        prev_data_in_waiting = 0
        while True:
            data_in_waiting = ser.in_waiting
            if(not data_in_waiting == prev_data_in_waiting):
                print(f"data in queue {data_in_waiting}")
                prev_data_in_waiting = data_in_waiting
                dt = time.perf_counter()-start_time
                print(f"freq : {1/dt}")
                start_time = time.perf_counter()
                
            time.sleep(0.001)


# Start sender and receiver in separate threads
start_time = time.perf_counter()
receiver_thread = threading.Thread(target=receiver)
sender_thread = threading.Thread(target=sender)

receiver_thread.start()
sender_thread.start()


receiver_thread.join()
sender_thread.join()



total_time = time.time() - start_time
print(f"Total time for data transmission: {total_time:.2f} seconds")

有人知道问题可能是什么吗？

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我尝试以 100 HZ 的速率发送 14 字节数据

我预计以 100 Hz 的速率接收 14 字节的数据

我以大约 60 Hz 的速率接收数据

Answer 1

如果将延迟计时器降低至 1ms，FTDI 的速率可高达 1kHz。这可以从 Windows 中的设备管理器访问。

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