我有两个线程会增加 CPU 开销。1. 以同步方式从套接字读取。2.等待接受来自其他客户端的连接
问题 1，我只是想读取来自客户端的任何数据，但我不能使用 readline，因为传入的数据有我标记的换行符以了解消息的标题结尾。所以我在线程中使用这种方式，但它增加了 CPU 开销
public static String convertStreamToString(TCPServerConnectionListner socket) throws UnsupportedEncodingException, IOException, InterruptedException {
BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getSocket().getInputStream()));
// At this point it is too early to read. So it most likely return false
System.out.println("Buffer Reader ready? " + reader.ready());
// StringBuilder to hold the response
StringBuilder sb = new StringBuilder();
// Indicator to show if we have started to receive data or not
boolean dataStreamStarted = false;
// How many times we went to sleep waiting for data
int sleepCounter = 0;
// How many times (max) we will sleep before bailing out
int sleepMaxCounter = 5;
// Sleep max counter after data started
int sleepMaxDataCounter = 50;
// How long to sleep for each cycle
int sleepTime = 5;
// Start time
long startTime = System.currentTimeMillis();
// This is a tight loop. Not sure what it will do to CPU
while (true) {
if (reader.ready()) {
sb.append((char) reader.read());
// Once started we do not expect server to stop in the middle and restart
dataStreamStarted = true;
} else {
Thread.sleep(sleepTime);
if (dataStreamStarted && (sleepCounter >= sleepMaxDataCounter)) {
System.out.println("Reached max sleep time of " + (sleepMaxDataCounter * sleepTime) + " ms after data started");
break;
} else {
if (sleepCounter >= sleepMaxCounter) {
System.out.println("Reached max sleep time of " + (sleepMaxCounter * sleepTime) + " ms. Bailing out");
// Reached max timeout waiting for data. Bail..
break;
}
}
sleepCounter++;
}
}
long endTime = System.currentTimeMillis();
System.out.println(sb.toString());
System.out.println("Time " + (endTime - startTime));
return sb.toString();
}
问题 2，我不知道这样做的最佳方法是什么，我只是有一个线程不断等待其他客户端并接受它。但这也需要大量的 CPU 开销。
// Listner to accept any client connection
@Override
public void run() {
while (true) {
try {
mutex.acquire();
if (!welcomeSocket.isClosed()) {
connectionSocket = welcomeSocket.accept();
// Thread.sleep(5);
}
} catch (IOException ex) {
Logger.getLogger(TCPServerConnectionListner.class.getName()).log(Level.SEVERE, null, ex);
} catch (InterruptedException ex) {
Logger.getLogger(TCPServerConnectionListner.class.getName()).log(Level.SEVERE, null, ex);
}
finally
{
mutex.release();
}
}
}
}
Profiler 图片也会有所帮助，但我想知道为什么 SwingWorker 线程要花那么多时间？
问题一的更新代码：
public static String convertStreamToString(TCPServerConnectionListner socket) throws UnsupportedEncodingException, IOException, InterruptedException {
byte[] resultBuff = new byte[0];
byte[] buff = new byte[65534];
int k = -1;
k = socket.getSocket().getInputStream().read(buff, 0, buff.length);
byte[] tbuff = new byte[resultBuff.length + k]; // temp buffer size = bytes already read + bytes last read
System.arraycopy(resultBuff, 0, tbuff, 0, resultBuff.length); // copy previous bytes
System.arraycopy(buff, 0, tbuff, resultBuff.length, k); // copy current lot
resultBuff = tbuff; // call the temp buffer as your result buff
return new String(resultBuff);
}
}
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