最近由于工作要求，需要对一个串口通讯设备进行压力测试，要求连续持续对串口设备发送指令，无间隔，测试设备是否会死机。
要求做到毫秒级，测试第三方的工具，基本上都无法达到毫秒级，最少的也是10毫秒。
于是就自己写代码测试。通过.net写，发现最少能达到1毫秒，但是有遗漏，看日志如下

2024-03-31 22:11:02 164 00 00
2024-03-31 22:11:02 165 00 00
2024-03-31 22:11:02 166 00 00
2024-03-31 22:11:02 167 00 00
2024-03-31 22:11:02 169 00 00
2024-03-31 22:11:02 170 00 00
2024-03-31 22:11:02 171 00 00
2024-03-31 22:11:02 172 00 00
2024-03-31 22:11:02 173 00 00
2024-03-31 22:11:02 175 00 00
2024-03-31 22:11:02 176 00 00
2024-03-31 22:11:02 178 00 00
2024-03-31 22:11:02 179 00 00
2024-03-31 22:11:02 181 00 00
2024-03-31 22:11:02 183 00 00
2024-03-31 22:11:02 184 00 00
2024-03-31 22:11:02 186 00 00
2024-03-31 22:11:02 188 00 00
2024-03-31 22:11:02 190 00 00
2024-03-31 22:11:02 191 00 00
2024-03-31 22:11:02 192 00 00
2024-03-31 22:11:02 194 00 00
2024-03-31 22:11:02 196 00 00
2024-03-31 22:11:02 198 00 00
2024-03-31 22:11:02 199 00 00
2024-03-31 22:11:02 201 00 00

时间后的三位数字是毫秒，发现偶尔会少一个毫秒。

用java写了一段测试，效果如下

2024-03-31 22:05:20.225 [main] DEBUG com.bonn.Test2 - [401190]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.225 [main] DEBUG com.bonn.Test2 - [401191]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.225 [main] DEBUG com.bonn.Test2 - [401192]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.225 [main] DEBUG com.bonn.Test2 - [401193]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.225 [main] DEBUG com.bonn.Test2 - [401194]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.225 [main] DEBUG com.bonn.Test2 - [401195]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.225 [main] DEBUG com.bonn.Test2 - [401196]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.225 [main] DEBUG com.bonn.Test2 - [401197]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.225 [main] DEBUG com.bonn.Test2 - [401198]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.225 [main] DEBUG com.bonn.Test2 - [401199]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.225 [main] DEBUG com.bonn.Test2 - [401200]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.225 [main] DEBUG com.bonn.Test2 - [401201]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.225 [main] DEBUG com.bonn.Test2 - [401202]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.225 [main] DEBUG com.bonn.Test2 - [401203]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.225 [main] DEBUG com.bonn.Test2 - [401204]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.225 [main] DEBUG com.bonn.Test2 - [401205]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.225 [main] DEBUG com.bonn.Test2 - [401206]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.225 [main] DEBUG com.bonn.Test2 - [401207]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.225 [main] DEBUG com.bonn.Test2 - [401208]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.225 [main] DEBUG com.bonn.Test2 - [401209]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.225 [main] DEBUG com.bonn.Test2 - [401210]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.225 [main] DEBUG com.bonn.Test2 - [401211]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.225 [main] DEBUG com.bonn.Test2 - [401212]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.225 [main] DEBUG com.bonn.Test2 - [401213]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401214]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401215]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401216]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401217]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401218]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401219]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401220]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401221]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401222]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401223]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401224]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401225]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401226]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401227]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401228]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401229]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401230]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401231]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401232]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401233]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401234]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401235]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401236]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401237]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401238]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401239]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401240]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401241]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401242]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401243]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401244]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401245]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 
2024-03-31 22:05:20.226 [main] DEBUG com.bonn.Test2 - [401246]---> 发送：FC FC FC 0A 00 02 20 00 28 2E 

测试结果

会发现同一毫秒发了好多条。从上面的日志来看，java完胜c#啊
我用了十多年的.net的，今年才开始用java，这差距就这么大吗？
c#用的是System.IO.Ports;官方的库。
java用的是com.fazecast.jSerialComm.SerialPort，第三方的。

附录

.net部分源码

        static void Main(string[] args)
        {
            SerialPortHelper sp = new SerialPortHelper();
            sp.Open();
            for (int i = 0; i < 1000; i++)
            {
                byte[] bs = new byte[2];
                sp.Send(bs);
                Trace.WriteLine($"{DateTime.Now:yyyy-MM-dd HH:mm:ss fff} {bs.ByteToHexString()}");
            }
        }

            while (true) {
                i++;
                if (i > totalTimes) {
                    break;
                }
                synchronized (lock) {
                    try {
                        long curCommMillis = System.currentTimeMillis();
                        String[] strList = new String[2];
                        strList[1] = "FC FC FC 0A 00 02 20 00 28 2E";
      
                        byte[] sendBuff = ByteHelper.hex2byte(strList[1]);
 
                        // Send(sendBuff);
                        sp.writeBytes(sendBuff, sendBuff.length);
                        logger.debug(String.format("[%s]---> 发送：%s ", i, byteToString(sendBuff)));


                    } catch (Exception ex) {
                        logger.error("main exception 01:", ex);
                    }
                }
            }

关键代码已经发出来了，其他无关的不影响主没有发。
大家可以讨论一下，是我使用的方法不对吗，请指正。