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import java.util.List;

import java.lang.management.*;

import com.oracle.java.testlibrary.*;

import static com.oracle.java.testlibrary.Asserts.*;

/* @test TestPerfCountersAndMemoryPools

 * @bug 8023476

 * @library /testlibrary

 * @summary Tests that a MemoryPoolMXBeans and PerfCounters for metaspace

 *          report the same data.

 * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:-UseCompressedOops -XX:-UseCompressedKlassPointers -XX:+UseSerialGC -XX:+UsePerfData -Xint TestPerfCountersAndMemoryPools

 * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:+UseCompressedOops -XX:+UseCompressedKlassPointers -XX:+UseSerialGC -XX:+UsePerfData -Xint TestPerfCountersAndMemoryPools

 */

public class TestPerfCountersAndMemoryPools {

    public static void main(String[] args) throws Exception {

        checkMemoryUsage("Metaspace", "sun.gc.metaspace");

        if (InputArguments.contains("-XX:+UseCompressedKlassPointers") && Platform.is64bit()) {

            checkMemoryUsage("Compressed Class Space", "sun.gc.compressedclassspace");

        }

    }

    private static MemoryPoolMXBean getMemoryPool(String memoryPoolName) {

        List<MemoryPoolMXBean> pools = ManagementFactory.getMemoryPoolMXBeans();

        for (MemoryPoolMXBean pool : pools) {

            if (pool.getName().equals(memoryPoolName)) {

                return pool;

            }

        }

        throw new RuntimeException("Excpted to find a memory pool with name " +

                                   memoryPoolName);

    }

    private static void checkMemoryUsage(String memoryPoolName, String perfNS)

        throws Exception {

        MemoryPoolMXBean pool = getMemoryPool(memoryPoolName);

        // Must do a GC to update performance counters

        System.gc();

        assertEQ(getMinCapacity(perfNS), pool.getUsage().getInit());

        // Must do a second GC to update the perfomance counters again, since

        // the call pool.getUsage().getInit() could have allocated some

        // metadata.

        System.gc();

        assertEQ(getUsed(perfNS), pool.getUsage().getUsed());

        assertEQ(getCapacity(perfNS), pool.getUsage().getCommitted());

    }

    private static long getMinCapacity(String ns) throws Exception {

        return PerfCounters.findByName(ns + ".minCapacity").longValue();

    }

    private static long getCapacity(String ns) throws Exception {

        return PerfCounters.findByName(ns + ".capacity").longValue();

    }

    private static long getUsed(String ns) throws Exception {

        return PerfCounters.findByName(ns + ".used").longValue();

    }

}