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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

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 *

 * 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

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 */

/**

 * @test TestPeriodicCollection

 * @requires vm.gc.G1

 * @requires vm.compMode != "Xcomp"

 * @summary Verify that heap shrinks when the application is idle.

 * @library /test/lib /

 * @modules java.base/jdk.internal.misc

 * @modules java.management/sun.management

 * @run main/othervm -XX:MaxNewSize=32M -XX:InitialHeapSize=48M -Xmx128M -XX:MinHeapFreeRatio=5 -XX:MaxHeapFreeRatio=25 -XX:+UseG1GC -XX:G1PeriodicGCInterval=3000 -XX:+G1PeriodicGCInvokesConcurrent -Xlog:gc,gc+periodic=debug,gc+ergo+heap=debug TestPeriodicCollection

 * @run main/othervm -XX:MaxNewSize=32M -XX:InitialHeapSize=48M -Xmx128M -XX:MinHeapFreeRatio=5 -XX:MaxHeapFreeRatio=25 -XX:+UseG1GC -XX:G1PeriodicGCInterval=3000 -XX:-G1PeriodicGCInvokesConcurrent -Xlog:gc,gc+periodic=debug,gc+ergo+heap=debug TestPeriodicCollection

 */

import com.sun.management.HotSpotDiagnosticMXBean;

import gc.testlibrary.Helpers;

import java.lang.management.GarbageCollectorMXBean;

import java.lang.management.ManagementFactory;

import java.lang.management.MemoryUsage;

import java.text.NumberFormat;

import static jdk.test.lib.Asserts.*;

public class TestPeriodicCollection {

    public static final String MIN_FREE_RATIO_FLAG_NAME = "MinHeapFreeRatio";

    public static final String MAX_FREE_RATIO_FLAG_NAME = "MaxHeapFreeRatio";

    private static final int IDLE_TIME = 7 * 1000;

    private static boolean gcOccurred() {

        for (GarbageCollectorMXBean b : ManagementFactory.getGarbageCollectorMXBeans()) {

            if (b.getCollectionCount() != 0) {

                return true;

            }

        }

        return false;

    }

    public static void main(String[] args) {

        MemoryUsage muInitial = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage();

        MemoryUsagePrinter.printMemoryUsage("initial", muInitial);

        if (gcOccurred()) {

          System.out.println("At least one garbage collection occurred. Exiting as this may have already shrunk the heap.");

          return;

        }

        try {

            Thread.sleep(IDLE_TIME);

        } catch (InterruptedException ie) {

            System.err.println("Skipped. Failed to wait for idle collection");

        }

        MemoryUsage muAfter = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage();

        MemoryUsagePrinter.printMemoryUsage("after", muAfter);

        assertLessThan(muAfter.getCommitted(), muInitial.getCommitted(), String.format(

                "committed free heap size is not less than committed full heap size, heap hasn't been shrunk?%n"

                + "%s = %s%n%s = %s",

                MIN_FREE_RATIO_FLAG_NAME,

                ManagementFactory.getPlatformMXBean(HotSpotDiagnosticMXBean.class)

                    .getVMOption(MIN_FREE_RATIO_FLAG_NAME).getValue(),

                MAX_FREE_RATIO_FLAG_NAME,

                ManagementFactory.getPlatformMXBean(HotSpotDiagnosticMXBean.class)

                    .getVMOption(MAX_FREE_RATIO_FLAG_NAME).getValue()

        ));

    }

}

/**

 * Prints memory usage to standard output

 */

class MemoryUsagePrinter {

    public static final NumberFormat NF = Helpers.numberFormatter();

    public static void printMemoryUsage(String label, MemoryUsage memusage) {

        float freeratio = 1f - (float) memusage.getUsed() / memusage.getCommitted();

        System.out.format("[%-24s] init: %-7s, used: %-7s, comm: %-7s, freeRatio ~= %.1f%%%n",

                label,

                NF.format(memusage.getInit()),

                NF.format(memusage.getUsed()),

                NF.format(memusage.getCommitted()),

                freeratio * 100

        );

    }

}