1 /*
   2  * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 package gc.arguments;
  25 
  26 /*
  27  * @test TestSelectDefaultGC
  28  * @summary Test selection of GC when no GC option is specified
  29  * @bug 8068582
  30  * @key gc
  31  * @library /test/lib
  32  * @requires vm.gc.G1
  33  * @modules java.base/jdk.internal.misc
  34  *          java.management
  35  * @run driver gc.arguments.TestSelectDefaultGC
  36  */
  37 
  38 import jdk.test.lib.process.OutputAnalyzer;
  39 import jdk.test.lib.process.ProcessTools;
  40 
  41 public class TestSelectDefaultGC {
  42     public static void assertVMOption(OutputAnalyzer output, String option, boolean value) {
  43         output.shouldMatch(" " + option + " .*=.* " + value + " ");
  44     }
  45 
  46     public static void testDefaultGC(boolean actAsServer) throws Exception {
  47         String[] args = new String[] {
  48           "-XX:" + (actAsServer ? "+" : "-") + "AlwaysActAsServerClassMachine",
  49           "-XX:" + (actAsServer ? "-" : "+") + "NeverActAsServerClassMachine",
  50           "-XX:+PrintFlagsFinal",
  51           "-version"
  52         };
  53 
  54         // Start VM without specifying GC
  55         ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(args);
  56         OutputAnalyzer output = new OutputAnalyzer(pb.start());
  57         output.shouldHaveExitValue(0);
  58 
  59         final boolean isServer = actAsServer;
  60 
  61         // Verify GC selection
  62         // G1 is default for server class machines
  63         assertVMOption(output, "UseG1GC",            isServer);
  64         // Serial is default for non-server class machines
  65         assertVMOption(output, "UseSerialGC",        !isServer);
  66         // CMS is never default
  67         assertVMOption(output, "UseConcMarkSweepGC", false);
  68     }
  69 
  70     public static void main(String[] args) throws Exception {
  71         // Test server class machine
  72         testDefaultGC(false);
  73 
  74         // Test non-server class machine
  75         testDefaultGC(true);
  76     }
  77 }