test/hotspot/jtreg/serviceability/jvmti/HeapMonitor/MyPackage/HeapMonitorStatObjectCorrectnessTest.java

rev 47593 : [mq]: heap15

@@ -25,62 +25,90 @@
 
 /**
  * @test
  * @build Frame HeapMonitor
  * @summary Verifies the JVMTI Heap Monitor Statistics
- * @compile HeapMonitorStatCorrectnessTest.java
- * @run main/othervm/native -agentlib:HeapMonitor MyPackage.HeapMonitorStatCorrectnessTest
+ * @compile HeapMonitorStatObjectCorrectnessTest.java
+ * @run main/othervm/native -agentlib:HeapMonitor MyPackage.HeapMonitorStatObjectCorrectnessTest
  */
 
-public class HeapMonitorStatCorrectnessTest {
+/** This test is checking the object allocation path works with heap sampling. */
+public class HeapMonitorStatObjectCorrectnessTest {
 
   // Do 100000 iterations and expect maxIteration / multiplier samples.
   private static final int maxIteration = 100000;
-  private static int array[];
+  private static BigObject obj;
 
   private native static boolean statsHaveExpectedNumberSamples(int expected, int percentError);
 
-  private static void allocate(int size) {
+  private static void allocate() {
     for (int j = 0; j < maxIteration; j++) {
-      array = new int[size];
+      obj = new BigObject();
     }
   }
 
   public static void main(String[] args) {
-    int sizes[] = {1000, 10000, 100000};
-
-    for (int currentSize : sizes) {
-      System.out.println("Testing size " + currentSize);
+    final int sizeObject = 1400;
 
       // 111 is as good a number as any.
       final int samplingMultiplier = 111;
-      HeapMonitor.enableSampling(samplingMultiplier * currentSize);
+    HeapMonitor.enableSampling(samplingMultiplier * sizeObject);
 
       if (!HeapMonitor.areSamplingStatisticsZero()) {
         throw new RuntimeException("Statistics should be null to begin with.");
       }
 
-      allocate(currentSize);
+    allocate();
 
-      // For simplifications, we ignore the array memory usage for array internals (with the array
-      // sizes requested, it should be a negligible oversight).
+    // For simplifications, the code is allocating:
+    //   (BigObject size) * maxIteration.
+    //
+    // We ignore the class memory usage apart from field memory usage for BigObject. BigObject
+    // allocates 250 long, so 2000 bytes, so whatever is used for the class is negligible.
       //
       // That means that with maxIterations, the loop in the method allocate requests:
-      //    maxIterations * currentSize * 4 bytes (4 for integers)
+    //    maxIterations * 2000 bytes.
       //
-      // Via the enable sampling, the code requests a sample every samplingMultiplier * currentSize bytes.
+    // Via the enable sampling, the code requests a sample every samplingMultiplier * sizeObject bytes.
       //
       // Therefore, the expected sample number is:
-      //   (maxIterations * currentSize * 4) / (samplingMultiplier * currentSize);
+    //   (maxIterations * sizeObject) / (samplingMultiplier * sizeObject);
+    //
+    // Which becomes:
+    //   maxIterations / samplingMultiplier
       double expected = maxIteration;
-      expected *= 4;
       expected /= samplingMultiplier;
 
       // 10% error ensures a sanity test without becoming flaky.
-      if (!statsHaveExpectedNumberSamples((int) expected, 10)) {
+    if (!HeapMonitor.statsHaveExpectedNumberSamples((int) expected, 10)) {
         throw new RuntimeException("Statistics should show about " + expected + " samples.");
       }
 
       HeapMonitor.disableSampling();
     }
+
+  /**
+   * Big class on purpose to just be able to ignore the class memory space overhead.
+   *
+   * Class contains 175 long fields, so 175 * 8 = 1400 bytes.
+   */
+  private static class BigObject {
+    private long a0_0, a0_1, a0_2, a0_3, a0_4, a0_5, a0_6, a0_7, a0_8, a0_9;
+    private long a1_0, a1_1, a1_2, a1_3, a1_4, a1_5, a1_6, a1_7, a1_8, a1_9;
+    private long a2_0, a2_1, a2_2, a2_3, a2_4, a2_5, a2_6, a2_7, a2_8, a2_9;
+    private long a3_0, a3_1, a3_2, a3_3, a3_4, a3_5, a3_6, a3_7, a3_8, a3_9;
+    private long a4_0, a4_1, a4_2, a4_3, a4_4, a4_5, a4_6, a4_7, a4_8, a4_9;
+    private long a5_0, a5_1, a5_2, a5_3, a5_4, a5_5, a5_6, a5_7, a5_8, a5_9;
+    private long a6_0, a6_1, a6_2, a6_3, a6_4, a6_5, a6_6, a6_7, a6_8, a6_9;
+    private long a7_0, a7_1, a7_2, a7_3, a7_4, a7_5, a7_6, a7_7, a7_8, a7_9;
+    private long a8_0, a8_1, a8_2, a8_3, a8_4, a8_5, a8_6, a8_7, a8_8, a8_9;
+    private long a9_0, a9_1, a9_2, a9_3, a9_4, a9_5, a9_6, a9_7, a9_8, a9_9;
+    private long a10_0, a10_1, a10_2, a10_3, a10_4, a10_5, a10_6, a10_7, a10_8, a10_9;
+    private long a11_0, a11_1, a11_2, a11_3, a11_4, a11_5, a11_6, a11_7, a11_8, a11_9;
+    private long a12_0, a12_1, a12_2, a12_3, a12_4, a12_5, a12_6, a12_7, a12_8, a12_9;
+    private long a13_0, a13_1, a13_2, a13_3, a13_4, a13_5, a13_6, a13_7, a13_8, a13_9;
+    private long a14_0, a14_1, a14_2, a14_3, a14_4, a14_5, a14_6, a14_7, a14_8, a14_9;
+    private long a15_0, a15_1, a15_2, a15_3, a15_4, a15_5, a15_6, a15_7, a15_8, a15_9;
+    private long a16_0, a16_1, a16_2, a16_3, a16_4, a16_5, a16_6, a16_7, a16_8, a16_9;
+    private long a17_0, a17_1, a17_2, a17_3, a17_4;
   }
 }