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. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 package org.openjdk.bench.java.io; 24 25 import java.io.File; 26 import java.io.FileOutputStream; 27 import java.io.IOException; 28 import java.io.RandomAccessFile; 29 import java.util.concurrent.TimeUnit; 30 31 import org.openjdk.jmh.annotations.Benchmark; 32 import org.openjdk.jmh.annotations.BenchmarkMode; 33 import org.openjdk.jmh.annotations.Level; 34 import org.openjdk.jmh.annotations.Mode; 35 import org.openjdk.jmh.annotations.OutputTimeUnit; 36 import org.openjdk.jmh.annotations.Param; 37 import org.openjdk.jmh.annotations.Scope; 38 import org.openjdk.jmh.annotations.Setup; 39 import org.openjdk.jmh.annotations.State; 40 import org.openjdk.jmh.annotations.TearDown; 41 42 /** 43 * Tests the overheads of I/O API. 44 * This test is known to depend heavily on disk subsystem performance. 45 */ 46 @BenchmarkMode(Mode.Throughput) 47 @OutputTimeUnit(TimeUnit.MILLISECONDS) 48 @State(Scope.Thread) 49 public class RandomAccessRead { 50 51 @Param("1000000") 52 private int fileSize; 53 54 private RandomAccessFile raf; 55 private long offset; 56 private int deltaIndex; 57 private int[] deltas; 58 private File f; 59 60 @Setup(Level.Trial) 61 public void beforeRun() throws IOException { 62 f = File.createTempFile("RandomAccessBench", ".bin"); 63 try (FileOutputStream fos = new FileOutputStream(f)) { 64 for (int i = 0; i < fileSize; i++) { 65 fos.write((byte) i); 66 } 67 } 68 deltas = new int[]{1, 2, 3, 5, 7, 11, 13, 17, 19, 23}; 69 } 70 71 @TearDown(Level.Trial) 72 public void afterRun() throws IOException { 73 f.delete(); 74 } 75 76 @Setup(Level.Iteration) 77 public void beforeIteration() throws IOException { 78 raf = new RandomAccessFile(f, "rw"); 79 offset = 0; 80 deltaIndex = 0; 81 } 82 83 @TearDown(Level.Iteration) 84 public void afterIteration() throws IOException { 85 raf.close(); 86 } 87 88 @Benchmark 89 public int test() throws IOException { 90 offset = offset + deltas[deltaIndex]; 91 if (offset >= fileSize) { 92 offset = 0; 93 } 94 deltaIndex++; 95 if (deltaIndex >= deltas.length) { 96 deltaIndex = 0; 97 } 98 raf.seek(offset); 99 return raf.read(); 100 } 101 102 }