GetTotalSafepointTime.java

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 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
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 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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/*
 * @test
 * @bug     4858522
 * @summary Basic unit test of HotspotRuntimeMBean.getTotalSafepointTime()
 * @author  Steve Bohne
 */

/*
 * This test is just a sanity check and does not check for the correct value.
 */

import sun.management.*;

public class GetTotalSafepointTime {

    private static HotspotRuntimeMBean mbean =
        (HotspotRuntimeMBean)ManagementFactoryHelper.getHotspotRuntimeMBean();

    private static final long NUM_THREAD_DUMPS = 100;

    // Careful with these values.
    private static final long MIN_VALUE_FOR_PASS = 1;
    private static final long MAX_VALUE_FOR_PASS = Long.MAX_VALUE;

    private static boolean trace = false;

    public static void main(String args[]) throws Exception {
        if (args.length > 0 && args[0].equals("trace")) {
            trace = true;
        }

        // Thread.getAllStackTraces() should cause safepoints.
        // If this test is failing because it doesn't,
        // MIN_VALUE_FOR_PASS should be reset to 0
        for (int i = 0; i < NUM_THREAD_DUMPS; i++) {
             Thread.getAllStackTraces();
        }

        long value = mbean.getTotalSafepointTime();

        if (trace) {
            System.out.println("Total safepoint time (ms): " + value);
        }

        if (value < MIN_VALUE_FOR_PASS || value > MAX_VALUE_FOR_PASS) {
            throw new RuntimeException("Total safepoint time " +
                                       "illegal value: " + value + " ms " +
                                       "(MIN = " + MIN_VALUE_FOR_PASS + "; " +
                                       "MAX = " + MAX_VALUE_FOR_PASS + ")");
        }

        for (int i = 0; i < 2 * NUM_THREAD_DUMPS; i++) {
             Thread.getAllStackTraces();
        }
        long value2 = mbean.getTotalSafepointTime();

        if (trace) {
            System.out.println("Total safepoint time2 (ms): " + value2);
        }

        if (value2 <= value) {
            throw new RuntimeException("Total safepoint time " +
                                       "did not increase " +
                                       "(value = " + value + "; " +
                                       "value2 = " + value2 + ")");
        }

        System.out.println("Test passed.");
    }
}