--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/java/org/openjdk/gcbench/retain/Finalizables.java	Thu Oct 26 12:11:04 2017 +0200
@@ -0,0 +1,42 @@
+package org.openjdk.gcbench.retain;
+
+import org.openjdk.jmh.annotations.*;
+
+import java.util.concurrent.TimeUnit;
+
+@Warmup(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
+@Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
+@Fork(1)
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.NANOSECONDS)
+@Threads(Threads.MAX)
+@State(Scope.Benchmark)
+public class Finalizables {
+
+    Object retain;
+
+    @Param({"100000"})
+    private int size;
+
+    @Setup
+    public void setup() {
+        Object[] objs = new Object[size];
+        for (int c = 0; c < size; c++) {
+            objs[c] = new Finalizable();
+        }
+        retain = objs;
+    }
+
+    @Benchmark
+    public Object test() {
+        return new Object();
+    }
+
+    public static class Finalizable {
+        @Override
+        protected void finalize() throws Throwable {
+            super.finalize();
+        }
+    }
+
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/java/org/openjdk/gcbench/retain/LargeGraphPhantomRef.java	Thu Oct 26 12:11:04 2017 +0200
@@ -0,0 +1,49 @@
+package org.openjdk.gcbench.retain;
+
+import org.openjdk.jmh.annotations.*;
+
+import java.lang.ref.PhantomReference;
+import java.lang.ref.Reference;
+import java.lang.ref.ReferenceQueue;
+import java.lang.ref.SoftReference;
+import java.util.TreeMap;
+import java.util.concurrent.TimeUnit;
+
+@Warmup(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
+@Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
+@Fork(1)
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.NANOSECONDS)
+@Threads(Threads.MAX)
+@State(Scope.Benchmark)
+public class LargeGraphPhantomRef {
+
+    PhantomReference<TreeMap<String, Object>> ref;
+    ReferenceQueue<Object> rq;
+
+    @Param({"100000"})
+    private int size;
+
+    public TreeMap<String, Object> createTreeMap() {
+        TreeMap<String, Object> t = new TreeMap<>();
+        for (int c = 0; c < size; c++) {
+            t.put("String" + c, new Object());
+        }
+        return t;
+    }
+
+    @Setup
+    public void setup() {
+        rq = new ReferenceQueue<>();
+        ref = new PhantomReference<>(createTreeMap(), rq);
+    }
+
+    @Benchmark
+    public Object test() {
+        if (rq.poll() != null) {
+            ref = new PhantomReference<>(createTreeMap(), rq);
+        }
+        return new byte[100];
+    }
+
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/java/org/openjdk/gcbench/retain/SoftRefs.java	Thu Oct 26 12:11:04 2017 +0200
@@ -0,0 +1,46 @@
+package org.openjdk.gcbench.retain;
+
+import org.openjdk.jmh.annotations.*;
+
+import java.lang.ref.Reference;
+import java.lang.ref.ReferenceQueue;
+import java.lang.ref.SoftReference;
+import java.lang.ref.WeakReference;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.WeakHashMap;
+import java.util.concurrent.TimeUnit;
+
+@Warmup(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
+@Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
+@Fork(1)
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.NANOSECONDS)
+@Threads(Threads.MAX)
+@State(Scope.Benchmark)
+public class SoftRefs {
+
+    Reference[] retain;
+    ReferenceQueue<Object> rq;
+
+    @Param({"100000"})
+    private int size;
+
+    @Setup
+    public void setup() {
+        rq = new ReferenceQueue<>();
+        Reference[] list = new Reference[size];
+        for (int c = 0; c < size; c++) {
+            list[c] = new SoftReference<>(new Object(), rq);
+        }
+        retain = list;
+    }
+
+    @Benchmark
+    public Object test() {
+        while (rq.poll() != null); // drain
+        // allocation pressure to trigger GCs
+        return new Object();
+    }
+
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/java/org/openjdk/gcbench/retain/WeakHashMaps.java	Thu Oct 26 12:11:04 2017 +0200
@@ -0,0 +1,44 @@
+package org.openjdk.gcbench.retain;
+
+import org.openjdk.jmh.annotations.*;
+
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.Optional;
+import java.util.WeakHashMap;
+import java.util.concurrent.TimeUnit;
+
+@Warmup(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
+@Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
+@Fork(1)
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.NANOSECONDS)
+@Threads(Threads.MAX)
+@State(Scope.Benchmark)
+public class WeakHashMaps {
+
+    Object retain;
+
+    @Param({"100000"})
+    private int size;
+
+    @Setup
+    public void setup() {
+        WeakHashMap<Object, Object> map = new WeakHashMap<>();
+        for (int c = 0; c < size; c++) {
+            Object v = new Object();
+            // deadly-embrace to keep weak key strongly reachable;
+            // also make sure the value is one dereference forward, in order
+            // to let VM discover the reference first, not the referent.
+            map.put(v, Optional.of(v));
+        }
+        retain = map;
+    }
+
+    @Benchmark
+    public Object test() {
+        // allocation pressure to trigger GCs
+        return new Object();
+    }
+
+}