--- old/test/hotspot/jtreg/gc/stress/systemgc/TestSystemGC.java	2017-11-06 21:03:04.071702422 +0100
+++ new/test/hotspot/jtreg/gc/stress/systemgc/TestSystemGC.java	2017-11-06 21:03:03.656689767 +0100
@@ -90,6 +90,7 @@
     private long delayMS;
 
     SystemGCTask(long delayMS) {
+System.err.println("SystemGCTask with delay " + delayMS);
         this.delayMS = delayMS;
     }
 
@@ -97,12 +98,14 @@
     public void run() {
         while (!shouldExit()) {
             System.gc();
-            ThreadUtils.sleep(delayMS);
+            ThreadUtils.sleep(delayMS * 10);
         }
     }
 }
 
 public class TestSystemGC {
+    private static long endTime;
+
     private static final int numGroups = 7;
     private static final int numGCsPerGroup = 4;
 
@@ -133,8 +136,11 @@
 
         for (int i = 0; i < numGroups; i++) {
             for (int j = 0; j < numGCsPerGroup; j++) {
-                System.gc();
-                ThreadUtils.sleep(getDelayMS(i));
+               System.gc();
+               if (System.currentTimeMillis() >= endTime) {
+                   return;
+               }
+               ThreadUtils.sleep(getDelayMS(i));
             }
         }
     }
@@ -159,7 +165,8 @@
     }
 
     private static void runAllPhases() {
-        for (int i = 0; i < 4; i++) {
+        int i = 0;
+        while (i < 4 && System.currentTimeMillis() < endTime) {
             SystemGCTask gcTask =
                 (i % 2 == 1) ? createSystemGCTask(numGroups / 3) : null;
             ShortLivedAllocationTask shortTask =
@@ -178,15 +185,18 @@
             exitTask(longTask);
 
             ThreadUtils.sleep(1000);
+            i++;
         }
     }
 
     public static void main(String[] args) {
+        if (args.length > 0) {
+            int timeout = Integer.parseInt(args[0]) * 1000;
+            System.out.println("Running with timeout of " + timeout + "ms");
+            endTime = System.currentTimeMillis() + timeout;
+        }
         // First allocate the long lived objects and then run all phases.
         populateLongLived();
         runAllPhases();
-        if (args.length > 0 && args[0].equals("long")) {
-            runAllPhases();
-        }
     }
 }