1 /* 2 * Copyright (c) 2003, 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 /* 25 * @test 26 * @bug 4530538 27 * @summary Basic Test for HotspotThreadMBean.getInternalThreadCount() 28 * and getInternalThreadCpuTime() 29 * @author Mandy Chung 30 * @modules java.management/sun.management 31 * @run main/othervm -XX:+UsePerfData GetInternalThreads 32 */ 33 34 import sun.management.*; 35 import java.util.*; 36 import java.lang.management.ThreadMXBean; 37 import java.lang.management.ManagementFactory; 38 39 public class GetInternalThreads { 40 private final static HotspotThreadMBean mbean = 41 ManagementFactoryHelper.getHotspotThreadMBean(); 42 43 // Minimum number of VM internal threads 44 // VM thread, watcher thread, Low memory detector, compiler thread 45 private static final long MIN_VALUE_FOR_PASS = 4; 46 private static final long MAX_VALUE_FOR_PASS = Long.MAX_VALUE; 47 48 public static void main(String[] args) throws Exception { 49 long value = mbean.getInternalThreadCount(); 50 51 if (value < MIN_VALUE_FOR_PASS || value > MAX_VALUE_FOR_PASS) { 52 throw new RuntimeException("Internal thread count " + 53 "illegal value: " + value + " " + 54 "(MIN = " + MIN_VALUE_FOR_PASS + "; " + 55 "MAX = " + MAX_VALUE_FOR_PASS + ")"); 56 } 57 58 System.out.println("Internal Thread Count = " + value); 59 60 ThreadMXBean thread = 61 ManagementFactory.getThreadMXBean(); 62 if (!thread.isThreadCpuTimeSupported()) { 63 System.out.println("Thread Cpu Time is not supported."); 64 return; 65 } 66 67 while(!testCPUTime()) { 68 Thread.sleep(100); 69 } 70 } 71 72 private static boolean testCPUTime() { 73 Map<String, Long> times = mbean.getInternalThreadCpuTimes(); 74 for(Map.Entry<String, Long> entry : times.entrySet()) { 75 String threadName = entry.getKey(); 76 long cpuTime = entry.getValue(); 77 System.out.println("CPU time = " + cpuTime + " for " + threadName); 78 if (cpuTime == -1) { 79 // Can happen when there is a race between a thread being created 80 // and the request to get its CPU time. The "/proc/..." structure might 81 // not be ready at that time and the routine will return -1. 82 System.out.println("Retry, proc structure might not be ready (-1)"); 83 return false; 84 } 85 if (cpuTime < 0) { 86 throw new RuntimeException("Illegal CPU time: " + cpuTime); 87 } 88 } 89 return true; 90 } 91 }