Initial Contribution
diff --git a/tools/preload/ClassRank.java b/tools/preload/ClassRank.java
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+/*
+ * 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.util.Comparator;
+
+/**
+ * Ranks classes for preloading based on how long their operations took
+ * and how early the operations happened. Higher ranked classes come first.
+ */
+class ClassRank implements Comparator<Operation> {
+
+ /**
+ * Increase this number to add more weight to classes which were loaded
+ * earlier.
+ */
+ static final int SEQUENCE_WEIGHT = 500; // 5 ms
+
+ static final int BUCKET_SIZE = 5;
+
+ public int compare(Operation a, Operation b) {
+ // Higher ranked operations should come first.
+ int result = rankOf(b) - rankOf(a);
+ if (result != 0) {
+ return result;
+ }
+
+ // Make sure we don't drop one of two classes w/ the same rank.
+ // If a load and an initialization have the same rank, it's OK
+ // to treat the operations equally.
+ return a.loadedClass.name.compareTo(b.loadedClass.name);
+ }
+
+ /** Ranks the given operation. */
+ private static int rankOf(Operation o) {
+ return o.medianExclusiveTimeMicros()
+ + SEQUENCE_WEIGHT / (o.index / BUCKET_SIZE + 1);
+ }
+}
+
+