1 /* 2 * Copyright (c) 2014 Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 package org.openjdk.bench.java.io; 26 27 import java.io.File; 28 import java.io.FileOutputStream; 29 import java.io.IOException; 30 import java.nio.ByteBuffer; 31 import java.nio.channels.FileChannel; 32 import java.nio.file.StandardOpenOption; 33 import java.util.concurrent.TimeUnit; 34 35 import org.openjdk.jmh.annotations.*; 36 37 /** 38 * Tests the overheads of I/O API. 39 * This test is known to depend heavily on disk subsystem performance. 40 */ 41 @BenchmarkMode(Mode.Throughput) 42 @OutputTimeUnit(TimeUnit.MILLISECONDS) 43 @State(Scope.Thread) 44 public class FileChannelRead { 45 46 @Param("1000000") 47 private int fileSize; 48 49 private File f; 50 private FileChannel fc; 51 private ByteBuffer bb; 52 53 @Setup(Level.Trial) 54 public void beforeRun() throws IOException { 55 f = File.createTempFile("FileChannelReadBench", ".bin"); 56 try (FileOutputStream fos = new FileOutputStream(f)) { 57 for (int i = 0; i < fileSize; i++) { 58 fos.write((byte) i); 59 } 60 } 61 bb = ByteBuffer.allocate(1); 62 } 63 64 @TearDown(Level.Trial) 65 public void afterRun() throws IOException { 66 f.delete(); 67 } 68 69 @Setup(Level.Iteration) 70 public void beforeIteration() throws IOException { 71 fc = FileChannel.open(f.toPath(), StandardOpenOption.READ); 72 } 73 74 @TearDown(Level.Iteration) 75 public void afterIteration() throws IOException { 76 fc.close(); 77 } 78 79 @Benchmark 80 public void test() throws IOException { 81 int ret = fc.read(bb); 82 bb.flip(); 83 if (ret == -1) { 84 // start over 85 fc.position(0); 86 } 87 } 88 89 }