Merge branch 'readonly-p4-master'

core/java/android/os/Debug.java

@@ -632,6 +632,25 @@ href="{@docRoot}guide/developing/tools/traceview.html">Traceview: A Graphical Lo
      */
     public static final native int getBinderDeathObjectCount();
 
+    /**
+     * Primes the register map cache.
+     *
+     * Only works for classes in the bootstrap class loader.  Does not
+     * cause classes to be loaded if they're not already present.
+     *
+     * The classAndMethodDesc argument is a concatentation of the VM-internal
+     * class descriptor, method name, and method descriptor.  Examples:
+     *     Landroid/os/Looper;.loop:()V
+     *     Landroid/app/ActivityThread;.main:([Ljava/lang/String;)V
+     *
+     * @param classAndMethodDesc the method to prepare
+     *
+     * @hide
+     */
+    public static final boolean cacheRegisterMap(String classAndMethodDesc) {
+        return VMDebug.cacheRegisterMap(classAndMethodDesc);
+    }
+
     /**
      * API for gathering and querying instruction counts.
      *

core/java/com/android/internal/os/ZygoteInit.java

@@ -93,7 +93,26 @@ public class ZygoteInit {
 
     /** Controls whether we should preload resources during zygote init. */
     private static final boolean PRELOAD_RESOURCES = true;
-    
+
+    /**
+     * List of methods we "warm up" in the register map cache.  These were
+     * chosen because they appeared on the stack in GCs in multiple
+     * applications.
+     *
+     * This is in a VM-ready format, to minimize string processing.  If a
+     * class is not already loaded, or a method is not found, the entry
+     * will be skipped.
+     *
+     * This doesn't really merit a separately-generated input file at this
+     * time.  The list is fairly short, and the consequences of failure
+     * are minor.
+     */
+    private static final String[] REGISTER_MAP_METHODS = {
+        // (currently not doing any)
+        //"Landroid/app/Activity;.setContentView:(I)V",
+    };
+
+
     /**
      * Invokes a static "main(argv[]) method on class "className".
      * Converts various failing exceptions into RuntimeExceptions, with
@@ -318,6 +337,45 @@ public class ZygoteInit {
         }
     }
 
+    /**
+     * Pre-caches register maps for methods that are commonly used.
+     */
+    private static void cacheRegisterMaps() {
+        String failed = null;
+        int failure;
+        long startTime = System.nanoTime();
+
+        failure = 0;
+
+        for (int i = 0; i < REGISTER_MAP_METHODS.length; i++) {
+            String str = REGISTER_MAP_METHODS[i];
+
+            if (!Debug.cacheRegisterMap(str)) {
+                if (failed == null)
+                    failed = str;
+                failure++;
+            }
+        }
+
+        long delta = System.nanoTime() - startTime;
+
+        if (failure == REGISTER_MAP_METHODS.length) {
+            if (REGISTER_MAP_METHODS.length > 0) {
+                Log.i(TAG,
+                    "Register map caching failed (precise GC not enabled?)");
+            }
+            return;
+        }
+
+        Log.i(TAG, "Register map cache: found " +
+            (REGISTER_MAP_METHODS.length - failure) + " of " +
+            REGISTER_MAP_METHODS.length + " methods in " +
+            (delta / 1000000L) + "ms");
+        if (failure > 0) {
+            Log.i(TAG, "  First failure: " + failed);
+        }
+    }
+
     /**
      * Load in commonly used resources, so they can be shared across
      * processes.
@@ -510,6 +568,7 @@ public class ZygoteInit {
             EventLog.writeEvent(LOG_BOOT_PROGRESS_PRELOAD_START,
                 SystemClock.uptimeMillis());
             preloadClasses();
+            //cacheRegisterMaps();
             preloadResources();
             EventLog.writeEvent(LOG_BOOT_PROGRESS_PRELOAD_END,
                 SystemClock.uptimeMillis());