/*

 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.

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

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * 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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 * questions.

 */

import java.lang.management.ManagementFactory;

import java.lang.management.MemoryPoolMXBean;

import java.util.Objects;

import java.util.Optional;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

import com.oracle.java.testlibrary.Asserts;

import com.sun.management.ThreadMXBean;

import sun.hotspot.WhiteBox;

import sun.misc.Unsafe;

/**

 * Main class for tests on {@code SurvivorAlignmentInBytes} option.

 *

 * Typical usage is to obtain instance using fromArgs method, allocate objects

 * and verify that actual memory usage in tested heap space is close to

 * expected.

 */

public class SurvivorAlignmentTestMain {

    enum HeapSpace {

        EDEN,

        SURVIVOR,

        TENURED

    }

    public static final WhiteBox WHITE_BOX = WhiteBox.getWhiteBox();

    public static final long MAX_TENURING_THRESHOLD = Optional.ofNullable(

            SurvivorAlignmentTestMain.WHITE_BOX.getIntxVMFlag(

                    "MaxTenuringThreshold")).orElse(15L);

    /**

     * Regexp used to parse memory size params, like 2G, 34m or 15k.

     */

    private static final Pattern SIZE_REGEX

            = Pattern.compile("(?<size>[0-9]+)(?<multiplier>[GMKgmk])?");

    // Names of different heap spaces.

    private static final String DEF_NEW_EDEN = "Eden Space";

    private static final String DEF_NEW_SURVIVOR = "Survivor Space";

    private static final String PAR_NEW_EDEN = "Par Eden Space";

    private static final String PAR_NEW_SURVIVOR = "Par Survivor Space";

    private static final String PS_EDEN = "PS Eden Space";

    private static final String PS_SURVIVOR = "PS Survivor Space";

    private static final String G1_EDEN = "G1 Eden Space";

    private static final String G1_SURVIVOR = "G1 Survivor Space";

    private static final String SERIAL_TENURED = "Tenured Gen";

    private static final String CMS_TENURED = "CMS Old Gen";

    private static final String PS_TENURED = "PS Old Gen";

    private static final String G1_TENURED = "G1 Old Gen";

    private static final long G1_HEAP_REGION_SIZE = Optional.ofNullable(

            SurvivorAlignmentTestMain.WHITE_BOX.getUintxVMFlag(

                    "G1HeapRegionSize")).orElse(-1L);

    /**

     * Min size of free chunk in CMS generation.

     * An object allocated in CMS generation will at least occupy this amount

     * of bytes.

     */

    private static final long CMS_MIN_FREE_CHUNK_SIZE

            = 3L * Unsafe.ADDRESS_SIZE;

    private static final AlignmentHelper EDEN_SPACE_HELPER;

    private static final AlignmentHelper SURVIVOR_SPACE_HELPER;

    private static final AlignmentHelper TENURED_SPACE_HELPER;

    /**

     * Amount of memory that should be filled during a test run.

     */

    private final long memoryToFill;

    /**

     * The size of an objects that will be allocated during a test run.

     */

    private final long objectSize;

    /**

     * Amount of memory that will be actually occupied by an object in eden

     * space.

     */

    private final long actualObjectSize;

    /**

     * Storage for allocated objects.

     */

    private final Object[] garbage;

    /**

     * Heap space whose memory usage is a subject of assertions during the test

     * run.

     */

    private final HeapSpace testedSpace;

    private long[] baselinedThreadMemoryUsage = null;

    private long[] threadIds = null;

    /**

     * Initialize {@code EDEN_SPACE_HELPER}, {@code SURVIVOR_SPACE_HELPER} and

     * {@code TENURED_SPACE_HELPER} to represent heap spaces in use.

     *

     * Note that regardless to GC object's alignment in survivor space is

     * expected to be equal to {@code SurvivorAlignmentInBytes} value and

     * alignment in other spaces is expected to be equal to

     * {@code ObjectAlignmentInBytes} value.

     *

     * In CMS generation we can't allocate less then {@code MinFreeChunk} value,

     * for other CGs we expect that object of size {@code MIN_OBJECT_SIZE}

     * could be allocated as it is (of course, its size could be aligned

     * according to alignment value used in a particular space).

     *

     * For G1 GC MXBeans could report memory usage only with region size

     * precision (if an object allocated in some G1 heap region, then all region

     * will claimed as used), so for G1's spaces precision is equal to

     * {@code G1HeapRegionSize} value.

     */

    static {

        AlignmentHelper edenHelper = null;

        AlignmentHelper survivorHelper = null;

        AlignmentHelper tenuredHelper = null;

        for (MemoryPoolMXBean pool : ManagementFactory.getMemoryPoolMXBeans()) {

            switch (pool.getName()) {

                case SurvivorAlignmentTestMain.DEF_NEW_EDEN:

                case SurvivorAlignmentTestMain.PAR_NEW_EDEN:

                case SurvivorAlignmentTestMain.PS_EDEN:

                    Asserts.assertNull(edenHelper,

                            "Only one bean for eden space is expected.");

                    edenHelper = new AlignmentHelper(

                            AlignmentHelper.OBJECT_ALIGNMENT_IN_BYTES,

                            AlignmentHelper.OBJECT_ALIGNMENT_IN_BYTES,

                            AlignmentHelper.MIN_OBJECT_SIZE, pool);

                    break;

                case SurvivorAlignmentTestMain.G1_EDEN:

                    Asserts.assertNull(edenHelper,

                            "Only one bean for eden space is expected.");

                    edenHelper = new AlignmentHelper(

                            SurvivorAlignmentTestMain.G1_HEAP_REGION_SIZE,

                            AlignmentHelper.OBJECT_ALIGNMENT_IN_BYTES,

                            AlignmentHelper.MIN_OBJECT_SIZE, pool);

                    break;

                case SurvivorAlignmentTestMain.DEF_NEW_SURVIVOR:

                case SurvivorAlignmentTestMain.PAR_NEW_SURVIVOR:

                case SurvivorAlignmentTestMain.PS_SURVIVOR:

                    Asserts.assertNull(survivorHelper,

                            "Only one bean for survivor space is expected.");

                    survivorHelper = new AlignmentHelper(

                            AlignmentHelper.OBJECT_ALIGNMENT_IN_BYTES,

                            AlignmentHelper.SURVIVOR_ALIGNMENT_IN_BYTES,

                            AlignmentHelper.MIN_OBJECT_SIZE, pool);

                    break;

                case SurvivorAlignmentTestMain.G1_SURVIVOR:

                    Asserts.assertNull(survivorHelper,

                            "Only one bean for survivor space is expected.");

                    survivorHelper = new AlignmentHelper(

                            SurvivorAlignmentTestMain.G1_HEAP_REGION_SIZE,

                            AlignmentHelper.SURVIVOR_ALIGNMENT_IN_BYTES,

                            AlignmentHelper.MIN_OBJECT_SIZE, pool);

                    break;

                case SurvivorAlignmentTestMain.SERIAL_TENURED:

                case SurvivorAlignmentTestMain.PS_TENURED:

                case SurvivorAlignmentTestMain.G1_TENURED:

                    Asserts.assertNull(tenuredHelper,

                            "Only one bean for tenured space is expected.");

                    tenuredHelper = new AlignmentHelper(

                            AlignmentHelper.OBJECT_ALIGNMENT_IN_BYTES,

                            AlignmentHelper.OBJECT_ALIGNMENT_IN_BYTES,

                            AlignmentHelper.MIN_OBJECT_SIZE, pool);

                    break;

                case SurvivorAlignmentTestMain.CMS_TENURED:

                    Asserts.assertNull(tenuredHelper,

                            "Only one bean for tenured space is expected.");

                    tenuredHelper = new AlignmentHelper(

                            AlignmentHelper.OBJECT_ALIGNMENT_IN_BYTES,

                            AlignmentHelper.OBJECT_ALIGNMENT_IN_BYTES,

                            SurvivorAlignmentTestMain.CMS_MIN_FREE_CHUNK_SIZE,

                            pool);

                    break;

            }

        }

        EDEN_SPACE_HELPER = Objects.requireNonNull(edenHelper,

                "AlignmentHelper for eden space should be initialized.");

        SURVIVOR_SPACE_HELPER = Objects.requireNonNull(survivorHelper,

                "AlignmentHelper for survivor space should be initialized.");

        TENURED_SPACE_HELPER = Objects.requireNonNull(tenuredHelper,

                "AlignmentHelper for tenured space should be initialized.");

    }

    /**

     * Returns an SurvivorAlignmentTestMain instance constructed using CLI

     * options.

     *

     * Following options are expected:

     * <ul>

     *     <li>memoryToFill</li>

     *     <li>objectSize</li>

     * </ul>

     *

     * Both argument may contain multiplier suffix k, m or g.

     */

    public static SurvivorAlignmentTestMain fromArgs(String[] args) {

        Asserts.assertEQ(args.length, 3, "Expected three arguments: "

                + "memory size, object size and tested heap space name.");

        long memoryToFill = parseSize(args[0]);

        long objectSize = Math.max(parseSize(args[1]),

                AlignmentHelper.MIN_ARRAY_SIZE);

        HeapSpace testedSpace = HeapSpace.valueOf(args[2]);

        return new SurvivorAlignmentTestMain(memoryToFill, objectSize,

                testedSpace);

    }

    /**

     * Returns a value parsed from a string with format

     * <integer><multiplier>.

     */

    private static long parseSize(String sizeString) {

        Matcher matcher = SIZE_REGEX.matcher(sizeString);

        Asserts.assertTrue(matcher.matches(),

                "sizeString should have following format \"[0-9]+([MBK])?\"");

        long size = Long.valueOf(matcher.group("size"));

        if (matcher.group("multiplier") != null) {

            long K = 1024L;

            // fall through multipliers

            switch (matcher.group("multiplier").toLowerCase()) {

                case "g":

                    size *= K;

                case "m":

                    size *= K;

                case "k":

                    size *= K;

            }

        }

        return size;

    }

    private SurvivorAlignmentTestMain(long memoryToFill, long objectSize,

            HeapSpace testedSpace) {

        this.objectSize = objectSize;

        this.memoryToFill = memoryToFill;

        this.testedSpace = testedSpace;

        AlignmentHelper helper = SurvivorAlignmentTestMain.EDEN_SPACE_HELPER;

        this.actualObjectSize = helper.getObjectSizeInThisSpace(

                this.objectSize);

        int arrayLength = helper.getObjectsCount(memoryToFill, this.objectSize);

        garbage = new Object[arrayLength];

    }

    /**

     * Allocate byte arrays to fill {@code memoryToFill} memory.

     */

    public void allocate() {

        int byteArrayLength = Math.max((int) (objectSize

                - Unsafe.ARRAY_BYTE_BASE_OFFSET), 0);

        for (int i = 0; i < garbage.length; i++) {

            garbage[i] = new byte[byteArrayLength];

        }

    }

    /**

     * Release memory occupied after {@code allocate} call.

     */

    public void release() {

        for (int i = 0; i < garbage.length; i++) {

            garbage[i] = null;

        }

    }

    /**

     * Returns expected amount of memory occupied in a {@code heapSpace} by

     * objects referenced from {@code garbage} array.

     */

    public long getExpectedMemoryUsage() {

        AlignmentHelper alignmentHelper = getAlignmentHelper(testedSpace);

        return alignmentHelper.getExpectedMemoryUsage(objectSize,

                garbage.length);

    }

    /**

     * Verifies that memory usage in a {@code heapSpace} deviates from

     * {@code expectedUsage} for no more than {@code MAX_RELATIVE_DEVIATION}.

     */

    public void verifyMemoryUsage(long expectedUsage) {

        AlignmentHelper alignmentHelper = getAlignmentHelper(testedSpace);

        long actualMemoryUsage = alignmentHelper.getActualMemoryUsage();

        boolean otherThreadsAllocatedMemory = areOtherThreadsAllocatedMemory();

        long memoryUsageDiff = Math.abs(actualMemoryUsage - expectedUsage);

        long maxAllowedUsageDiff

                = alignmentHelper.getAllowedMemoryUsageDeviation(expectedUsage);

        System.out.println("Verifying memory usage in space: " + testedSpace);

        System.out.println("Allocated objects count: " + garbage.length);

        System.out.println("Desired object size: " + objectSize);

        System.out.println("Actual object size: " + actualObjectSize);

        System.out.println("Expected object size in space: "

                + alignmentHelper.getObjectSizeInThisSpace(objectSize));

        System.out.println("Expected memory usage: " + expectedUsage);

        System.out.println("Actual memory usage: " + actualMemoryUsage);

        System.out.println("Memory usage diff: " + memoryUsageDiff);

        System.out.println("Max allowed usage diff: " + maxAllowedUsageDiff);

        if (memoryUsageDiff > maxAllowedUsageDiff

                && otherThreadsAllocatedMemory) {

            System.out.println("Memory usage diff is incorrect, but it seems "

                    + "like someone else allocated objects");

            return;

        }

        Asserts.assertLTE(memoryUsageDiff, maxAllowedUsageDiff,

                "Actual memory usage should not deviate from expected for " +

                        "more then " + maxAllowedUsageDiff);

    }

    /**

     * Baselines amount of memory allocated by each thread.

     */

    public void baselineMemoryAllocation() {

        ThreadMXBean bean = (ThreadMXBean) ManagementFactory.getThreadMXBean();

        threadIds = bean.getAllThreadIds();

        baselinedThreadMemoryUsage = bean.getThreadAllocatedBytes(threadIds);

    }

    /**

     * Checks if threads other then the current thread were allocating objects

     * after baselinedThreadMemoryUsage call.

     *

     * If baselinedThreadMemoryUsage was not called, then this method will return

     * {@code false}.

     */

    public boolean areOtherThreadsAllocatedMemory() {

        if (baselinedThreadMemoryUsage == null) {

            return false;

        }

        ThreadMXBean bean = (ThreadMXBean) ManagementFactory.getThreadMXBean();

        long currentMemoryAllocation[]

                = bean.getThreadAllocatedBytes(threadIds);

        boolean otherThreadsAllocatedMemory = false;

        System.out.println("Verifying amount of memory allocated by threads:");

        for (int i = 0; i < threadIds.length; i++) {

            System.out.format("Thread %d%nbaseline allocation: %d"

                            + "%ncurrent allocation:%d%n", threadIds[i],

                    baselinedThreadMemoryUsage[i], currentMemoryAllocation[i]);

            System.out.println(bean.getThreadInfo(threadIds[i]));

            long bytesAllocated = Math.abs(currentMemoryAllocation[i]

                    - baselinedThreadMemoryUsage[i]);

            if (bytesAllocated > 0

                    && threadIds[i] != Thread.currentThread().getId()) {

                otherThreadsAllocatedMemory = true;

            }

        }

        return otherThreadsAllocatedMemory;

    }

    @Override

    public String toString() {

        StringBuilder builder = new StringBuilder();

        builder.append(String.format("SurvivorAlignmentTestMain info:%n"));

        builder.append(String.format("Desired object size: %d%n", objectSize));

        builder.append(String.format("Memory to fill: %d%n", memoryToFill));

        builder.append(String.format("Objects to be allocated: %d%n",

                garbage.length));

        builder.append(String.format("Alignment helpers to be used: %n"));

        for (HeapSpace heapSpace: HeapSpace.values()) {

            builder.append(String.format("For space %s:%n%s%n", heapSpace,

                    getAlignmentHelper(heapSpace)));

        }

        return builder.toString();

    }

    /**

     * Returns {@code AlignmentHelper} for a space {@code heapSpace}.

     */

    public static AlignmentHelper getAlignmentHelper(HeapSpace heapSpace) {

        switch (heapSpace) {

            case EDEN:

                return SurvivorAlignmentTestMain.EDEN_SPACE_HELPER;

            case SURVIVOR:

                return SurvivorAlignmentTestMain.SURVIVOR_SPACE_HELPER;

            case TENURED:

                return SurvivorAlignmentTestMain.TENURED_SPACE_HELPER;

            default:

                throw new Error("Unexpected heap space: " + heapSpace);

        }

    }

}