Slow HTTPS Upload provokes High CPU Load

Install Wildfly 9.0.0 CR1 Activate HTTPS in config Deploy a sample webappliction (e.g. https://tomcat.apache.org/tomcat-6.0-doc/appdev/sample/ should work too, although no doPost implemented) Adjust the following client code (https address, upload file) Run the code CPU Load will increase to 100% during the sleeps of the HTTPS client TestUndertowLoad.java package undertowtest; import java.io.DataOutputStream; import java.io.File; import java.io.FileNotFoundException; import java.io.IOException; import java.io.RandomAccessFile; import java.net.URL; import javax.net.ssl.HttpsURLConnection; /** * Tests the Undertow module, how it behaves in case of a HTTPS client which sends * its POST data very slowly. */ public class TestUndertowLoad { /** * Starter method of the test. * * @param args Arguments, not used * * @ throws IOException If a connection to webserver occured. */ public static void main( String [] args) throws IOException { String host = "localhost:8443" ; String uploadFile = "/opt/ import /testfile.bin" ; int chunkSize = 50; int sleepTime = 1000; String url = "https: //" + host + "/sample/hello" ; URL obj = new URL(url); HttpsURLConnection con = (HttpsURLConnection)obj.openConnection(); con.setRequestMethod( "POST" ); byte [] data = readFile( new File(uploadFile)); con.setFixedLengthStreamingMode(data.length); // send data using outputstream con.setDoOutput( true ); System .out.println( "Sending 'POST' request to URL : " + url+ "\n" ); DataOutputStream wr = new DataOutputStream(con.getOutputStream()); int index = 0; while (index < data.length) { // slow upload to provoke https://issues.jboss.org/browse/UNDERTOW-345 // CPU load will rise to 100 percent during the sleeps wr.writeByte(data[index]); System .out.print( "." ); if ((index % chunkSize) == (chunkSize-1)) { try { System .out.println( "Chunk sent, sleeping..." ); Thread .sleep(sleepTime); } catch (InterruptedException e) { e.printStackTrace(); } } index++; } wr.flush(); wr.close(); int responseCode = con.getResponseCode(); System .out.println( "Response Code : " + responseCode); } private static byte [] readFile(File file) throws IOException { byte [] ret; try { RandomAccessFile f = new RandomAccessFile(file, "r" ); try { ret = new byte [( int )f.length()]; f.read(ret); } finally { f.close(); } } catch (FileNotFoundException e) { ret = null ; } return ret; } }

This is the recommended solution for people looking to fix the CPU problem. Just set the read-timeout in standalone.xml, and High CPU Load is gone (even if the client sends all bytes within the timeout). <https-listener name="https" socket-binding="https" security-realm="UndertowRealm" read-timeout="20000" />