| /* |
| * Copyright (c) 2003, 2015, 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 |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| /* |
| * @test |
| * @bug 4530538 |
| * @summary Basic unit test of RuntimeMXBean.getUptime() |
| * @author Alexei Guibadoulline |
| */ |
| |
| import java.lang.management.*; |
| |
| public class UpTime { |
| static final long DELAY = 5; // Seconds |
| static final long TIMEOUT = 30; // Minutes |
| static final long MULTIPLIER = 1000; // millisecond ticks |
| |
| private static final RuntimeMXBean metrics |
| = ManagementFactory.getRuntimeMXBean(); |
| |
| public static void main(String argv[]) throws Exception { |
| long jvmStartTime = metrics.getStartTime(); |
| // this will get an aproximate JVM uptime before starting this test |
| long jvmUptime = System.currentTimeMillis() - jvmStartTime; |
| long systemStartOuter = System_milliTime(); |
| long metricsStart = metrics.getUptime(); |
| long systemStartInner = System_milliTime(); |
| |
| // This JVM might have been running for some time if this test runs |
| // in samevm mode. The sanity check should apply to the test uptime. |
| long testUptime = metricsStart - jvmUptime; |
| |
| // If uptime is more than 30 minutes then it looks like a bug in |
| // the method |
| if (testUptime > TIMEOUT * 60 * MULTIPLIER) |
| throw new RuntimeException("Uptime of the JVM is more than 30 " |
| + "minutes (" |
| + (metricsStart / 60 / MULTIPLIER) |
| + " minutes)."); |
| |
| // Wait for DELAY seconds |
| Object o = new Object(); |
| while (System_milliTime() < systemStartInner + DELAY * MULTIPLIER) { |
| synchronized (o) { |
| try { |
| o.wait(DELAY * 1000); |
| } catch (Exception e) { |
| e.printStackTrace(); |
| throw e; |
| } |
| } |
| } |
| |
| long systemEndInner = System_milliTime(); |
| long metricsEnd = metrics.getUptime(); |
| long systemEndOuter = System_milliTime(); |
| |
| long systemDifferenceInner = systemEndInner - systemStartInner; |
| long systemDifferenceOuter = systemEndOuter - systemStartOuter; |
| long metricsDifference = metricsEnd - metricsStart; |
| |
| // Check the flow of time in RuntimeMXBean.getUptime(). See the |
| // picture below. |
| // The measured times can be off by 1 due to conversions from |
| // nanoseconds to milliseconds, using different channels to read the |
| // HR timer and rounding error. Bigger difference will make the test |
| // fail. |
| if (metricsDifference - systemDifferenceInner < -1) |
| throw new RuntimeException("Flow of the time in " |
| + "RuntimeMXBean.getUptime() (" |
| + metricsDifference + ") is slower than " |
| + " in system (" + systemDifferenceInner |
| + ")"); |
| if (metricsDifference - systemDifferenceOuter > 1) |
| throw new RuntimeException("Flow of the time in " |
| + "RuntimeMXBean.getUptime() (" |
| + metricsDifference + ") is faster than " |
| + "in system (" + systemDifferenceOuter |
| + ")"); |
| |
| System.out.println("Test passed."); |
| } |
| |
| private static long System_milliTime() { |
| return System.nanoTime() / 1000000; // nanoseconds / milliseconds; |
| } |
| } |
| |
| /* |
| |
| A picture to describe the second testcase that checks the flow of time in |
| RuntimeMXBean.getUptime() |
| |
| |
| start |
| o1 u1 i1 Sleep for DELAY minutes i2 u2 o2 |
| |-------|---|---|--------------------------------|---|---|---------------> time |
| |
| |
| The following inequality (checked by the test) must always be true: |
| |
| o2-o1 >= u2-u1 >= i2-i1 |
| |
| In the test: |
| |
| i1 - systemStartInner |
| i2 - systemEndInner |
| o1 - systemStartOuter |
| o2 - systemEndOuter |
| u1 - metricsStart |
| u2 - metricsEnd |
| |
| */ |