Simplified algorithm used to generate the preloaded-classes list. Generated a new preloaded-classes file.
diff --git a/tools/preload/WritePreloadedClassFile.java b/tools/preload/WritePreloadedClassFile.java
index b209af0..96c539b 100644
--- a/tools/preload/WritePreloadedClassFile.java
+++ b/tools/preload/WritePreloadedClassFile.java
@@ -24,12 +24,18 @@
import java.util.TreeSet;
/**
- * Writes /frameworks/base/preloaded-classes. Also updates LoadedClass.preloaded
- * fields and writes over compiled log file.
+ * Writes /frameworks/base/preloaded-classes. Also updates
+ * {@link LoadedClass#preloaded} fields and writes over compiled log file.
*/
public class WritePreloadedClassFile {
- public static void main(String[] args) throws IOException, ClassNotFoundException {
+ /**
+ * Preload any class that take longer to load than MIN_LOAD_TIME_MICROS us.
+ */
+ static final int MIN_LOAD_TIME_MICROS = 1250;
+
+ public static void main(String[] args) throws IOException,
+ ClassNotFoundException {
if (args.length != 1) {
System.err.println("Usage: WritePreloadedClassFile [compiled log]");
System.exit(-1);
@@ -44,48 +50,64 @@
// Open preloaded-classes file for output.
Writer out = new BufferedWriter(new OutputStreamWriter(
- new FileOutputStream(Policy.getPreloadedClassFileName()),
+ 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.\n");
- out.write("# percent=" + Proc.PERCENTAGE_TO_PRELOAD
- + ", weight=" + ClassRank.SEQUENCE_WEIGHT
- + ", bucket_size=" + ClassRank.BUCKET_SIZE
- + "\n");
+ 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");
+ /*
+ * 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 all classes that were loaded by at least 2 apps, if both
- // apps run at the same time, they'll share memory.
+ // 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()) {
- if (!loadedClass.isPreloadable()) {
- continue;
- }
-
- Set<String> appNames = loadedClass.applicationNames();
-
- if (appNames.size() > 3) {
+ Set<String> names = loadedClass.processNames();
+ if (shouldPreload(loadedClass) && names.size() > 1) {
toPreload.add(loadedClass);
}
}
- // Try to make individual apps start faster by preloading slowest
- // classes.
+ 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()) {
- toPreload.addAll(proc.highestRankedClasses());
+ 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(toPreload.size() + " classes will be preloaded.");
+ System.out.println("Added " + (toPreload.size() - initialSize)
+ + " more to speed up applications.");
- // Make classes that were already loaded by the zygote explicit.
+ 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.
- addAllClassesFor("zygote", root, toPreload);
+ addAllClassesFrom("zygote", root, toPreload);
for (LoadedClass loadedClass : toPreload) {
- out.write(loadedClass.name);
- out.write('\n');
+ out.write(loadedClass.name + "\n");
}
out.close();
@@ -97,18 +119,26 @@
root.toFile(rootFile);
}
- private static void addAllClassesFor(String packageName, Root root,
- Set<LoadedClass> toPreload) {
+ private static void addAllClassesFrom(String processName, Root root,
+ Set<LoadedClass> toPreload) {
for (Proc proc : root.processes.values()) {
- if (proc.name.equals(packageName)) {
+ if (proc.name.equals(processName)) {
for (Operation operation : proc.operations) {
- // TODO: I'm not sure how the zygote loaded classes that
- // aren't supposed to be preloadable...
- if (operation.loadedClass.isPreloadable()) {
+ 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;
+ }
}