--- /dev/null	2018-11-26 11:49:18.255023023 +0100
+++ new/test/hotspot/jtreg/gc/shenandoah/TestGCThreadGroups.java	2018-11-26 21:30:31.443858149 +0100
@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2017, 2018, Red Hat, Inc. All rights reserved.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+/**
+ * @test TestGCThreadGroups
+ * @summary Test Shenandoah GC uses concurrent/parallel threads correctly
+ *
+ * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ConcGCThreads=2 -XX:ParallelGCThreads=4 -Xmx16m                                         -Dtarget=1000 TestGCThreadGroups
+ * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:-UseDynamicNumberOfGCThreads            -Xmx16m                                         -Dtarget=1000 TestGCThreadGroups
+ * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:+UnlockDiagnosticVMOptions -XX:+ForceDynamicNumberOfGCThreads -Xmx16m                   -Dtarget=1000 TestGCThreadGroups
+ * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ConcGCThreads=2 -XX:ParallelGCThreads=4 -Xmx16m -XX:ShenandoahGCHeuristics=passive      -Dtarget=1000 TestGCThreadGroups
+ * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ConcGCThreads=2 -XX:ParallelGCThreads=4 -Xmx16m -XX:ShenandoahGCHeuristics=adaptive     -Dtarget=1000 TestGCThreadGroups
+ * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ConcGCThreads=2 -XX:ParallelGCThreads=4 -Xmx16m -XX:ShenandoahGCHeuristics=static       -Dtarget=1000 TestGCThreadGroups
+ * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ConcGCThreads=2 -XX:ParallelGCThreads=4 -Xmx16m -XX:ShenandoahGCHeuristics=compact      -Dtarget=100  TestGCThreadGroups
+ * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ConcGCThreads=2 -XX:ParallelGCThreads=4 -Xmx16m -XX:ShenandoahGCHeuristics=aggressive   -Dtarget=100  TestGCThreadGroups
+ * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ConcGCThreads=2 -XX:ParallelGCThreads=4 -Xmx16m -XX:ShenandoahGCHeuristics=traversal    -Dtarget=1000 TestGCThreadGroups
+ * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ConcGCThreads=4 -XX:ParallelGCThreads=2 -Xmx16m -XX:ShenandoahGCHeuristics=passive      -Dtarget=1000 TestGCThreadGroups
+ * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ConcGCThreads=4 -XX:ParallelGCThreads=2 -Xmx16m -XX:ShenandoahGCHeuristics=adaptive     -Dtarget=1000 TestGCThreadGroups
+ * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ConcGCThreads=4 -XX:ParallelGCThreads=2 -Xmx16m -XX:ShenandoahGCHeuristics=static       -Dtarget=1000 TestGCThreadGroups
+ * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ConcGCThreads=4 -XX:ParallelGCThreads=2 -Xmx16m -XX:ShenandoahGCHeuristics=compact      -Dtarget=100  TestGCThreadGroups
+ * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ConcGCThreads=4 -XX:ParallelGCThreads=2 -Xmx16m -XX:ShenandoahGCHeuristics=aggressive   -Dtarget=100  TestGCThreadGroups
+ * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ConcGCThreads=4 -XX:ParallelGCThreads=2 -Xmx16m -XX:ShenandoahGCHeuristics=traversal    -Dtarget=1000 TestGCThreadGroups
+*/
+
+public class TestGCThreadGroups {
+
+  static final long TARGET_MB = Long.getLong("target", 10_000); // 10 Gb allocation, around 1K cycles to handle
+  static final long STRIDE = 100_000;
+
+  static volatile Object sink;
+
+  public static void main(String[] args) throws Exception {
+    long count = TARGET_MB * 1024 * 1024 / 16;
+    for (long c = 0; c < count; c += STRIDE) {
+      for (long s = 0; s < STRIDE; s++) {
+        sink = new Object();
+      }
+      Thread.sleep(1);
+    }
+  }
+
+}