| /* |
| * Copyright (c) 2016, 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 |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| import java.io.IOException; |
| |
| import java.lang.management.BufferPoolMXBean; |
| import java.lang.management.ManagementFactory; |
| |
| import java.nio.ByteBuffer; |
| |
| import java.nio.channels.FileChannel; |
| |
| import java.nio.file.Path; |
| import java.nio.file.Paths; |
| |
| import static java.nio.file.StandardOpenOption.CREATE; |
| import static java.nio.file.StandardOpenOption.TRUNCATE_EXISTING; |
| import static java.nio.file.StandardOpenOption.WRITE; |
| |
| import java.util.List; |
| import java.util.Random; |
| |
| /* |
| * @test |
| * @requires sun.arch.data.model == "64" |
| * @modules java.management |
| * @build TestMaxCachedBufferSize |
| * @run main/othervm TestMaxCachedBufferSize |
| * @run main/othervm -Djdk.nio.maxCachedBufferSize=0 TestMaxCachedBufferSize |
| * @run main/othervm -Djdk.nio.maxCachedBufferSize=2000 TestMaxCachedBufferSize |
| * @run main/othervm -Djdk.nio.maxCachedBufferSize=100000 TestMaxCachedBufferSize |
| * @run main/othervm -Djdk.nio.maxCachedBufferSize=10000000 TestMaxCachedBufferSize |
| * @summary Test the implementation of the jdk.nio.maxCachedBufferSize property. |
| */ |
| public class TestMaxCachedBufferSize { |
| private static final int DEFAULT_ITERS = 10 * 1000; |
| private static final int DEFAULT_THREAD_NUM = 4; |
| |
| private static final int SMALL_BUFFER_MIN_SIZE = 4 * 1024; |
| private static final int SMALL_BUFFER_MAX_SIZE = 64 * 1024; |
| private static final int SMALL_BUFFER_DIFF_SIZE = |
| SMALL_BUFFER_MAX_SIZE - SMALL_BUFFER_MIN_SIZE; |
| |
| private static final int LARGE_BUFFER_MIN_SIZE = 512 * 1024; |
| private static final int LARGE_BUFFER_MAX_SIZE = 4 * 1024 * 1024; |
| private static final int LARGE_BUFFER_DIFF_SIZE = |
| LARGE_BUFFER_MAX_SIZE - LARGE_BUFFER_MIN_SIZE; |
| |
| private static final int LARGE_BUFFER_FREQUENCY = 100; |
| |
| private static final String FILE_NAME_PREFIX = "nio-out-file-"; |
| private static final int VERBOSE_PERIOD = 5 * 1000; |
| |
| private static int iters = DEFAULT_ITERS; |
| private static int threadNum = DEFAULT_THREAD_NUM; |
| |
| private static BufferPoolMXBean getDirectPool() { |
| final List<BufferPoolMXBean> pools = |
| ManagementFactory.getPlatformMXBeans(BufferPoolMXBean.class); |
| for (BufferPoolMXBean pool : pools) { |
| if (pool.getName().equals("direct")) { |
| return pool; |
| } |
| } |
| throw new Error("could not find direct pool"); |
| } |
| private static final BufferPoolMXBean directPool = getDirectPool(); |
| |
| // Each worker will do write operations on a file channel using |
| // buffers of various sizes. The buffer size is randomly chosen to |
| // be within a small or a large range. This way we can control |
| // which buffers can be cached (all, only the small ones, or none) |
| // by setting the jdk.nio.maxCachedBufferSize property. |
| private static class Worker implements Runnable { |
| private final int id; |
| private final Random random = new Random(); |
| private long smallBufferCount = 0; |
| private long largeBufferCount = 0; |
| |
| private int getWriteSize() { |
| int minSize = 0; |
| int diff = 0; |
| if (random.nextInt() % LARGE_BUFFER_FREQUENCY != 0) { |
| // small buffer |
| minSize = SMALL_BUFFER_MIN_SIZE; |
| diff = SMALL_BUFFER_DIFF_SIZE; |
| smallBufferCount += 1; |
| } else { |
| // large buffer |
| minSize = LARGE_BUFFER_MIN_SIZE; |
| diff = LARGE_BUFFER_DIFF_SIZE; |
| largeBufferCount += 1; |
| } |
| return minSize + random.nextInt(diff); |
| } |
| |
| private void loop() { |
| final String fileName = String.format("%s%d", FILE_NAME_PREFIX, id); |
| |
| try { |
| for (int i = 0; i < iters; i += 1) { |
| final int writeSize = getWriteSize(); |
| |
| // This will allocate a HeapByteBuffer. It should not |
| // be a direct buffer, otherwise the write() method on |
| // the channel below will not create a temporary |
| // direct buffer for the write. |
| final ByteBuffer buffer = ByteBuffer.allocate(writeSize); |
| |
| // Put some random data on it. |
| while (buffer.hasRemaining()) { |
| buffer.put((byte) random.nextInt()); |
| } |
| buffer.rewind(); |
| |
| final Path file = Paths.get(fileName); |
| try (FileChannel outChannel = FileChannel.open(file, CREATE, TRUNCATE_EXISTING, WRITE)) { |
| // The write() method will create a temporary |
| // direct buffer for the write and attempt to cache |
| // it. It's important that buffer is not a |
| // direct buffer, otherwise the temporary buffer |
| // will not be created. |
| long res = outChannel.write(buffer); |
| } |
| |
| if ((i + 1) % VERBOSE_PERIOD == 0) { |
| System.out.printf( |
| " Worker %3d | %8d Iters | Small %8d Large %8d | Direct %4d / %7dK\n", |
| id, i + 1, smallBufferCount, largeBufferCount, |
| directPool.getCount(), directPool.getTotalCapacity() / 1024); |
| } |
| } |
| } catch (IOException e) { |
| throw new Error("I/O error", e); |
| } |
| } |
| |
| @Override |
| public void run() { |
| loop(); |
| } |
| |
| public Worker(int id) { |
| this.id = id; |
| } |
| } |
| |
| public static void checkDirectBuffers(long expectedCount, long expectedMax) { |
| final long directCount = directPool.getCount(); |
| final long directTotalCapacity = directPool.getTotalCapacity(); |
| System.out.printf("Direct %d / %dK\n", |
| directCount, directTotalCapacity / 1024); |
| |
| // Note that directCount could be < expectedCount. This can |
| // happen if a GC occurs after one of the worker threads exits |
| // since its thread-local DirectByteBuffer could be cleaned up |
| // before we reach here. |
| if (directCount > expectedCount) { |
| throw new Error(String.format( |
| "inconsistent direct buffer total count, expected = %d, found = %d", |
| expectedCount, directCount)); |
| } |
| |
| if (directTotalCapacity > expectedMax) { |
| throw new Error(String.format( |
| "inconsistent direct buffer total capacity, expectex max = %d, found = %d", |
| expectedMax, directTotalCapacity)); |
| } |
| } |
| |
| public static void main(String[] args) { |
| final String maxBufferSizeStr = System.getProperty("jdk.nio.maxCachedBufferSize"); |
| final long maxBufferSize = |
| (maxBufferSizeStr != null) ? Long.valueOf(maxBufferSizeStr) : Long.MAX_VALUE; |
| |
| // We assume that the max cannot be equal to a size of a |
| // buffer that can be allocated (makes sanity checking at the |
| // end easier). |
| if ((SMALL_BUFFER_MIN_SIZE <= maxBufferSize && |
| maxBufferSize <= SMALL_BUFFER_MAX_SIZE) || |
| (LARGE_BUFFER_MIN_SIZE <= maxBufferSize && |
| maxBufferSize <= LARGE_BUFFER_MAX_SIZE)) { |
| throw new Error(String.format("max buffer size = %d not allowed", |
| maxBufferSize)); |
| } |
| |
| System.out.printf("Threads %d | Iterations %d | MaxBufferSize %d\n", |
| threadNum, iters, maxBufferSize); |
| System.out.println(); |
| |
| final Thread[] threads = new Thread[threadNum]; |
| for (int i = 0; i < threadNum; i += 1) { |
| threads[i] = new Thread(new Worker(i)); |
| threads[i].start(); |
| } |
| |
| try { |
| for (int i = 0; i < threadNum; i += 1) { |
| threads[i].join(); |
| } |
| } catch (InterruptedException e) { |
| throw new Error("join() interrupted!", e); |
| } |
| |
| // There is an assumption here that, at this point, only the |
| // cached DirectByteBuffers should be active. Given we |
| // haven't used any other DirectByteBuffers in this test, this |
| // should hold. |
| // |
| // Also note that we can only do the sanity checking at the |
| // end and not during the run given that, at any time, there |
| // could be buffers currently in use by some of the workers |
| // that will not be cached. |
| |
| System.out.println(); |
| if (maxBufferSize < SMALL_BUFFER_MAX_SIZE) { |
| // The max buffer size is smaller than all buffers that |
| // were allocated. No buffers should have been cached. |
| checkDirectBuffers(0, 0); |
| } else if (maxBufferSize < LARGE_BUFFER_MIN_SIZE) { |
| // The max buffer size is larger than all small buffers |
| // but smaller than all large buffers that were |
| // allocated. Only small buffers could have been cached. |
| checkDirectBuffers(threadNum, |
| (long) threadNum * (long) SMALL_BUFFER_MAX_SIZE); |
| } else { |
| // The max buffer size is larger than all buffers that |
| // were allocated. All buffers could have been cached. |
| checkDirectBuffers(threadNum, |
| (long) threadNum * (long) LARGE_BUFFER_MAX_SIZE); |
| } |
| } |
| } |