6849945: VM Periodic Task Thread CPU time = -1ns in HotspotThreadMBean.getInternalThreadCpuTimes()
Reviewed-by: sla
--- a/jdk/test/sun/management/HotspotThreadMBean/GetInternalThreads.java Tue Nov 12 17:40:26 2013 +0100
+++ b/jdk/test/sun/management/HotspotThreadMBean/GetInternalThreads.java Tue Nov 12 18:12:47 2013 +0100
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2003, 2008, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@@ -35,7 +35,7 @@
import java.lang.management.ManagementFactory;
public class GetInternalThreads {
- private static HotspotThreadMBean mbean =
+ private final static HotspotThreadMBean mbean =
ManagementFactoryHelper.getHotspotThreadMBean();
// Minimum number of VM internal threads
@@ -43,7 +43,7 @@
private static final long MIN_VALUE_FOR_PASS = 4;
private static final long MAX_VALUE_FOR_PASS = Long.MAX_VALUE;
- public static void main(String[] args) {
+ public static void main(String[] args) throws Exception {
long value = mbean.getInternalThreadCount();
if (value < MIN_VALUE_FOR_PASS || value > MAX_VALUE_FOR_PASS) {
@@ -62,17 +62,28 @@
return;
}
- Map times = mbean.getInternalThreadCpuTimes();
- Iterator iter = times.entrySet().iterator();
- for (; iter.hasNext(); ) {
- Map.Entry entry = (Map.Entry) iter.next();
- System.out.println(entry.getKey() +
- " CPU time = " + entry.getValue() + "ns");
- if (((Long) entry.getValue()).longValue() < 0) {
- throw new RuntimeException("Thread CPU time" +
- "illegal value: " + entry.getValue());
+ while(!testCPUTime()) {
+ Thread.sleep(100);
+ }
+ }
+
+ private static boolean testCPUTime() {
+ Map<String, Long> times = mbean.getInternalThreadCpuTimes();
+ for(Map.Entry<String, Long> entry : times.entrySet()) {
+ String threadName = entry.getKey();
+ long cpuTime = entry.getValue();
+ System.out.println("CPU time = " + cpuTime + " for " + threadName);
+ if (cpuTime == -1) {
+ // Can happen when there is a race between a thread being created
+ // and the request to get its CPU time. The "/proc/..." structure might
+ // not be ready at that time and the routine will return -1.
+ System.out.println("Retry, proc structure might not be ready (-1)");
+ return false;
+ }
+ if (cpuTime < 0) {
+ throw new RuntimeException("Illegal CPU time: " + cpuTime);
}
}
- System.out.println("Test passed.");
+ return true;
}
}