TestPerfCountersAndMemoryPools.java

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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
 * @requires vm.gc=="Serial" | vm.gc=="null"
 * @summary Tests that a MemoryPoolMXBeans and PerfCounters for metaspace
 *          report the same data.
 * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:-UseCompressedOops -XX:-UseCompressedClassPointers -XX:+UseSerialGC -XX:+UsePerfData TestPerfCountersAndMemoryPools
 * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:+UseCompressedOops -XX:+UseCompressedClassPointers -XX:+UseSerialGC -XX:+UsePerfData 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();
    }
}