1/* 2 * Copyright (C) 2008 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17import java.io.BufferedWriter; 18import java.io.FileOutputStream; 19import java.io.IOException; 20import java.io.OutputStreamWriter; 21import java.io.Writer; 22import java.nio.charset.Charset; 23import java.util.Set; 24import java.util.TreeSet; 25 26/** 27 * Writes /frameworks/base/preloaded-classes. Also updates 28 * {@link LoadedClass#preloaded} fields and writes over compiled log file. 29 */ 30public class WritePreloadedClassFile { 31 32 /** 33 * Preload any class that take longer to load than MIN_LOAD_TIME_MICROS us. 34 */ 35 static final int MIN_LOAD_TIME_MICROS = 1250; 36 37 /** 38 * Preload any class that was loaded by at least MIN_PROCESSES processes. 39 */ 40 static final int MIN_PROCESSES = 10; 41 42 public static void main(String[] args) throws IOException, 43 ClassNotFoundException { 44 if (args.length != 1) { 45 System.err.println("Usage: WritePreloadedClassFile [compiled log]"); 46 System.exit(-1); 47 } 48 String rootFile = args[0]; 49 Root root = Root.fromFile(rootFile); 50 51 // No classes are preloaded to start. 52 for (LoadedClass loadedClass : root.loadedClasses.values()) { 53 loadedClass.preloaded = false; 54 } 55 56 // Open preloaded-classes file for output. 57 Writer out = new BufferedWriter(new OutputStreamWriter( 58 new FileOutputStream(Policy.PRELOADED_CLASS_FILE), 59 Charset.forName("US-ASCII"))); 60 61 out.write("# Classes which are preloaded by" 62 + " com.android.internal.os.ZygoteInit.\n"); 63 out.write("# Automatically generated by frameworks/base/tools/preload/" 64 + WritePreloadedClassFile.class.getSimpleName() + ".java.\n"); 65 out.write("# MIN_LOAD_TIME_MICROS=" + MIN_LOAD_TIME_MICROS + "\n"); 66 out.write("# MIN_PROCESSES=" + MIN_PROCESSES + "\n"); 67 68 /* 69 * The set of classes to preload. We preload a class if: 70 * 71 * a) it's loaded in the bootclasspath (i.e., is a system class) 72 * b) it takes > MIN_LOAD_TIME_MICROS us to load, and 73 * c) it's loaded by more than one process, or it's loaded by an 74 * application (i.e., not a long running service) 75 */ 76 Set<LoadedClass> toPreload = new TreeSet<LoadedClass>(); 77 78 // Preload classes that were loaded by at least 2 processes. Hopefully, 79 // the memory associated with these classes will be shared. 80 for (LoadedClass loadedClass : root.loadedClasses.values()) { 81 Set<String> names = loadedClass.processNames(); 82 if (!Policy.isPreloadable(loadedClass)) { 83 continue; 84 } 85 86 if (names.size() >= MIN_PROCESSES || 87 (loadedClass.medianTimeMicros() > MIN_LOAD_TIME_MICROS && names.size() > 1)) { 88 toPreload.add(loadedClass); 89 } 90 } 91 92 int initialSize = toPreload.size(); 93 System.out.println(initialSize 94 + " classses were loaded by more than one app."); 95 96 // Preload eligable classes from applications (not long-running 97 // services). 98 for (Proc proc : root.processes.values()) { 99 if (proc.fromZygote() && !Policy.isService(proc.name)) { 100 for (Operation operation : proc.operations) { 101 LoadedClass loadedClass = operation.loadedClass; 102 if (shouldPreload(loadedClass)) { 103 toPreload.add(loadedClass); 104 } 105 } 106 } 107 } 108 109 System.out.println("Added " + (toPreload.size() - initialSize) 110 + " more to speed up applications."); 111 112 System.out.println(toPreload.size() 113 + " total classes will be preloaded."); 114 115 // Make classes that were implicitly loaded by the zygote explicit. 116 // This adds minimal overhead but avoid confusion about classes not 117 // appearing in the list. 118 addAllClassesFrom("zygote", root, toPreload); 119 120 for (LoadedClass loadedClass : toPreload) { 121 out.write(loadedClass.name + "\n"); 122 } 123 124 out.close(); 125 126 // Update data to reflect LoadedClass.preloaded changes. 127 for (LoadedClass loadedClass : toPreload) { 128 loadedClass.preloaded = true; 129 } 130 root.toFile(rootFile); 131 } 132 133 private static void addAllClassesFrom(String processName, Root root, 134 Set<LoadedClass> toPreload) { 135 for (Proc proc : root.processes.values()) { 136 if (proc.name.equals(processName)) { 137 for (Operation operation : proc.operations) { 138 boolean preloadable 139 = Policy.isPreloadable(operation.loadedClass); 140 if (preloadable) { 141 toPreload.add(operation.loadedClass); 142 } 143 } 144 } 145 } 146 } 147 148 /** 149 * Returns true if the class should be preloaded. 150 */ 151 private static boolean shouldPreload(LoadedClass clazz) { 152 return Policy.isPreloadable(clazz) 153 && clazz.medianTimeMicros() > MIN_LOAD_TIME_MICROS; 154 } 155} 156