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/*

 * @test TestMBeanCMS.java

 * @bug 6581734

 * @summary CMS Old Gen's collection usage is zero after GC which is incorrect

 * @modules java.management

 * @run main/othervm -Xmx512m -verbose:gc -XX:+UseConcMarkSweepGC TestMBeanCMS

 *

 */

import java.lang.management.GarbageCollectorMXBean;

import java.lang.management.ManagementFactory;

import java.lang.management.MemoryPoolMXBean;

import java.util.LinkedList;

import java.util.List;

// 6581734 states that memory pool usage via the mbean is wrong

// for CMS (zero, even after a collection).

//

// 6580448 states that the collection count similarly is wrong

// (stays at zero for CMS collections)

// -- closed as dup of 6581734 as the same fix resolves both.

public class TestMBeanCMS {

    private String poolName = "CMS";

    private String collectorName = "ConcurrentMarkSweep";

    public static void main(String [] args) {

        TestMBeanCMS t = null;

        if (args.length==2) {

            t = new TestMBeanCMS(args[0], args[1]);

        } else {

            System.out.println("Defaulting to monitor CMS pool and collector.");

            t = new TestMBeanCMS();

        }

        t.run();

    }

    public TestMBeanCMS(String pool, String collector) {

        poolName = pool;

        collectorName = collector;

    }

    public TestMBeanCMS() {

    }

    public void run() {

        // Use some memory, enough that we expect collections should

        // have happened.

        // Must run with options to ensure no stop the world full GC,

        // but e.g. at least one CMS cycle.

        allocationWork(300*1024*1024);

        System.out.println("Done allocationWork");

        // Verify some non-zero results are stored.

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

        int poolsFound = 0;

        int poolsWithStats = 0;

        for (int i=0; i<pools.size(); i++) {

            MemoryPoolMXBean pool = pools.get(i);

            String name = pool.getName();

            System.out.println("found pool: " + name);

            if (name.contains(poolName)) {

                long usage = pool.getCollectionUsage().getUsed();

                System.out.println(name + ": usage after GC = " + usage);

                poolsFound++;

                if (usage > 0) {

                    poolsWithStats++;

                }

            }

        }

        if (poolsFound == 0) {

            throw new RuntimeException("No matching memory pools found: test with -XX:+UseConcMarkSweepGC");

        }

        List<GarbageCollectorMXBean> collectors = ManagementFactory.getGarbageCollectorMXBeans();

        int collectorsFound = 0;

        int collectorsWithTime= 0;

        for (int i=0; i<collectors.size(); i++) {

            GarbageCollectorMXBean collector = collectors.get(i);

            String name = collector.getName();

            System.out.println("found collector: " + name);

            if (name.contains(collectorName)) {

                collectorsFound++;

                System.out.println(name + ": collection count = "

                                   + collector.getCollectionCount());

                System.out.println(name + ": collection time  = "

                                   + collector.getCollectionTime());

                if (collector.getCollectionCount() <= 0) {

                    throw new RuntimeException("collection count <= 0");

                }

                if (collector.getCollectionTime() > 0) {

                    collectorsWithTime++;

                }

            }

        }

        // verify:

        if (poolsWithStats < poolsFound) {

            throw new RuntimeException("pools found with zero stats");

        }

        if (collectorsWithTime<collectorsFound) {

            throw new RuntimeException("collectors found with zero time");

        }

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

    }

    public void allocationWork(long target) {

        long sizeAllocated = 0;

        List list = new LinkedList();

        long delay = 50;

        long count = 0;

        while (sizeAllocated < target) {

            int size = 1024*1024;

            byte [] alloc = new byte[size];

            if (count % 2 == 0) {

                list.add(alloc);

                sizeAllocated+=size;

                System.out.print(".");

            }

            try { Thread.sleep(delay); } catch (InterruptedException ie) { }

            count++;

        }

    }

}