1 files changed, 155 insertions, 0 deletions
diff --git a/tools/preload/WritePreloadedClassFile.java b/tools/preload/WritePreloadedClassFile.java
new file mode 100644
index 0000000..b067bc2
--- /dev/null
+++ b/tools/preload/WritePreloadedClassFile.java
@@ -0,0 +1,155 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.io.BufferedWriter;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.OutputStreamWriter;
+import java.io.Writer;
+import java.nio.charset.Charset;
+import java.util.Set;
+import java.util.TreeSet;
+
+/**
+ * Writes /frameworks/base/preloaded-classes. Also updates
+ * {@link LoadedClass#preloaded} fields and writes over compiled log file.
+ */
+public class WritePreloadedClassFile {
+
+    /**
+     * Preload any class that take longer to load than MIN_LOAD_TIME_MICROS us.
+     */
+    static final int MIN_LOAD_TIME_MICROS = 1250;
+
+    /**
+     * Preload any class that was loaded by at least MIN_PROCESSES processes.
+     */
+    static final int MIN_PROCESSES = 10;
+
+    public static void main(String[] args) throws IOException,
+            ClassNotFoundException {
+        if (args.length != 1) {
+            System.err.println("Usage: WritePreloadedClassFile [compiled log]");
+            System.exit(-1);
+        }
+        String rootFile = args[0];
+        Root root = Root.fromFile(rootFile);
+
+        // No classes are preloaded to start.
+        for (LoadedClass loadedClass : root.loadedClasses.values()) {
+            loadedClass.preloaded = false;
+        }
+
+        // Open preloaded-classes file for output.
+        Writer out = new BufferedWriter(new OutputStreamWriter(
+                new FileOutputStream(Policy.PRELOADED_CLASS_FILE),
+                Charset.forName("US-ASCII")));
+
+        out.write("# Classes which are preloaded by"
+                + " com.android.internal.os.ZygoteInit.\n");
+        out.write("# Automatically generated by frameworks/base/tools/preload/"
+            + WritePreloadedClassFile.class.getSimpleName() + ".java.\n");
+        out.write("# MIN_LOAD_TIME_MICROS=" + MIN_LOAD_TIME_MICROS + "\n");
+        out.write("# MIN_PROCESSES=" + MIN_PROCESSES + "\n");
+
+        /*
+         * The set of classes to preload. We preload a class if:
+         *
+         *  a) it's loaded in the bootclasspath (i.e., is a system class)
+         *  b) it takes > MIN_LOAD_TIME_MICROS us to load, and
+         *  c) it's loaded by more than one process, or it's loaded by an
+         *     application (i.e., not a long running service)
+         */
+        Set<LoadedClass> toPreload = new TreeSet<LoadedClass>();
+
+        // Preload classes that were loaded by at least 2 processes. Hopefully,
+        // the memory associated with these classes will be shared.
+        for (LoadedClass loadedClass : root.loadedClasses.values()) {
+            Set<String> names = loadedClass.processNames();
+            if (!Policy.isPreloadable(loadedClass)) {
+                continue;
+            }
+
+            if (names.size() >= MIN_PROCESSES ||
+                    (loadedClass.medianTimeMicros() > MIN_LOAD_TIME_MICROS && names.size() > 1)) {
+                toPreload.add(loadedClass);
+            }
+        }
+
+        int initialSize = toPreload.size();
+        System.out.println(initialSize
+                + " classses were loaded by more than one app.");
+
+        // Preload eligable classes from applications (not long-running
+        // services).
+        for (Proc proc : root.processes.values()) {
+            if (proc.fromZygote() && !Policy.isService(proc.name)) {
+                for (Operation operation : proc.operations) {
+                    LoadedClass loadedClass = operation.loadedClass;
+                    if (shouldPreload(loadedClass)) {
+                        toPreload.add(loadedClass);
+                    }
+                }
+            }
+        }
+
+        System.out.println("Added " + (toPreload.size() - initialSize)
+                + " more to speed up applications.");
+
+        System.out.println(toPreload.size()
+                + " total classes will be preloaded.");
+
+        // Make classes that were implicitly loaded by the zygote explicit.
+        // This adds minimal overhead but avoid confusion about classes not
+        // appearing in the list.
+        addAllClassesFrom("zygote", root, toPreload);
+
+        for (LoadedClass loadedClass : toPreload) {
+            out.write(loadedClass.name + "\n");
+        }
+
+        out.close();
+
+        // Update data to reflect LoadedClass.preloaded changes.
+        for (LoadedClass loadedClass : toPreload) {
+            loadedClass.preloaded = true;
+        }
+        root.toFile(rootFile);
+    }
+
+    private static void addAllClassesFrom(String processName, Root root,
+            Set<LoadedClass> toPreload) {
+        for (Proc proc : root.processes.values()) {
+            if (proc.name.equals(processName)) {
+                for (Operation operation : proc.operations) {
+                    boolean preloadable
+                            = Policy.isPreloadable(operation.loadedClass);
+                    if (preloadable) {
+                        toPreload.add(operation.loadedClass);
+                    }
+                }
+            }
+        }
+    }
+
+    /**
+     * Returns true if the class should be preloaded.
+     */
+    private static boolean shouldPreload(LoadedClass clazz) {
+        return Policy.isPreloadable(clazz)
+                && clazz.medianTimeMicros() > MIN_LOAD_TIME_MICROS;
+    }
+}