Merge "Add more debugging to the DigestTest" into marshmallow-cts-dev am: 1117338720

am: cf4b283f02

* commit 'cf4b283f02bdd2b17bc61e952d58a705dee81ba7':
  Add more debugging to the DigestTest

2 files changed, 103 insertions, 12 deletions

diff --git a/luni/src/test/java/com/android/org/bouncycastle/crypto/digests/DigestTest.java b/luni/src/test/java/com/android/org/bouncycastle/crypto/digests/DigestTest.java
index 8708214..fce8507 100644
--- a/luni/src/test/java/com/android/org/bouncycastle/crypto/digests/DigestTest.java
+++ b/luni/src/test/java/com/android/org/bouncycastle/crypto/digests/DigestTest.java
@@ -19,6 +19,7 @@ package com.android.org.bouncycastle.crypto.digests;
 import junit.framework.TestCase;
 import com.android.org.bouncycastle.crypto.Digest;
 import com.android.org.bouncycastle.crypto.ExtendedDigest;
+import tests.util.SummaryStatistics;
 
 /**
  * Implements unit tests for our JNI wrapper around OpenSSL. We use the
@@ -36,6 +37,7 @@ public class DigestTest extends TestCase {
      * @param newDigest The new digest implementation, provided by OpenSSL
      */
     public void doTestMessageDigest(Digest oldDigest, Digest newDigest) {
+        final int WARMUP = 10;
         final int ITERATIONS = 100;
 
         byte[] data = new byte[1024];
@@ -54,27 +56,31 @@ public class DigestTest extends TestCase {
             data[i] = (byte)i;
         }
 
-        long oldTime = 0;
-        long newTime = 0;
+        SummaryStatistics oldTime = new SummaryStatistics();
+        SummaryStatistics newTime = new SummaryStatistics();
 
-        for (int j = 0; j < ITERATIONS; j++) {
-            long t0 = System.currentTimeMillis();
+        for (int j = 0; j < ITERATIONS + WARMUP; j++) {
+            long t0 = System.nanoTime();
             for (int i = 0; i < 4; i++) {
                 oldDigest.update(data, 0, data.length);
             }
             int oldLength = oldDigest.doFinal(oldHash, 0);
-            long t1 = System.currentTimeMillis();
+            long t1 = System.nanoTime();
 
-            oldTime = oldTime + (t1 - t0);
+            if (j >= WARMUP) {
+                oldTime.add(t1 - t0);
+            }
 
-            long t2 = System.currentTimeMillis();
+            long t2 = System.nanoTime();
             for (int i = 0; i < 4; i++) {
                 newDigest.update(data, 0, data.length);
             }
             int newLength = newDigest.doFinal(newHash, 0);
-            long t3 = System.currentTimeMillis();
+            long t3 = System.nanoTime();
 
-            newTime = newTime + (t3 - t2);
+            if (j >= WARMUP) {
+              newTime.add(t3 - t2);
+            }
 
             assertEquals("Hash sizes must be equal", oldLength, newLength);
 
@@ -83,10 +89,13 @@ public class DigestTest extends TestCase {
             }
         }
 
-        System.out.println("Time for " + ITERATIONS + " x old hash processing: " + oldTime + " ms");
-        System.out.println("Time for " + ITERATIONS + " x new hash processing: " + newTime + " ms");
+        System.out.println("Time for " + ITERATIONS + " x old hash processing: "
+                + oldTime.toString());
+        System.out.println("Time for " + ITERATIONS + " x new hash processing: "
+                + newTime.toString());
 
-        assertTrue("New hash should be faster", newTime < oldTime);
+        assertTrue("New hash should be faster:\nold=" + oldTime.toString() + "\nnew="
+                + newTime.toString(), newTime.mean() < oldTime.mean());
     }
 
     /**
diff --git a/support/src/test/java/tests/util/SummaryStatistics.java b/support/src/test/java/tests/util/SummaryStatistics.java
new file mode 100644
index 0000000..4ce0a04
--- /dev/null
+++ b/support/src/test/java/tests/util/SummaryStatistics.java
@@ -0,0 +1,82 @@
+/*
+ * Copyright 2015 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.
+ */
+
+package tests.util;
+
+public class SummaryStatistics {
+  /** The number of values seen. */
+  private int numValues;
+
+  /** Sum of the values. */
+  private double sum;
+
+  /** Sum of the squares of the values added. */
+  private double squaresSum;
+
+  /** The previously added value. */
+  private double lastValue;
+
+  public SummaryStatistics() {
+  }
+
+  private double square(double value) {
+    return value * value;
+  }
+
+  /** Add a new value to the values seen. */
+  public void add(double value) {
+    sum += value - lastValue;
+    squaresSum += square(value) - square(lastValue);
+    numValues++;
+    lastValue = value;
+  }
+
+  /** Mean of the values seen. */
+  public double mean() {
+    return sum / numValues;
+  }
+
+  /** Variance of the values seen. */
+  public double var() {
+    return (squaresSum / numValues) - square(mean());
+  }
+
+  /** Standard deviation of the values seen. */
+  public double stddev() {
+    return Math.sqrt(var());
+  }
+
+  /** Coefficient of variation of the values seen. */
+  public double coeffVar() {
+    return stddev() / mean();
+  }
+
+  public String toString() {
+    StringBuilder sb = new StringBuilder("SummaryStatistics{");
+    sb.append("n=");
+    sb.append(numValues);
+    sb.append(",mean=");
+    sb.append(mean());
+    sb.append(",var=");
+    sb.append(var());
+    sb.append(",stddev=");
+    sb.append(stddev());
+    sb.append(",coeffVar=");
+    sb.append(coeffVar());
+    sb.append('}');
+    return sb.toString();
+  }
+}