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23
24/*
25 * @test TestParallelGCThreads
26 * @key gc
27 * @bug 8059527 8081382
28 * @summary Tests argument processing for ParallelGCThreads
29 * @library /test/lib
30 * @modules java.base/jdk.internal.misc
31 *          java.management
32 * @run driver TestParallelGCThreads
33 */
34
35import jdk.test.lib.Asserts;
36import jdk.test.lib.process.OutputAnalyzer;
37import jdk.test.lib.process.ProcessTools;
38
39public class TestParallelGCThreads {
40
41  public static void main(String args[]) throws Exception {
42    testFlags();
43    testDefaultValue();
44  }
45
46  private static final String flagName = "ParallelGCThreads";
47
48  // uint ParallelGCThreads = 23 {product}
49  private static final String printFlagsFinalPattern = " *uint *" + flagName + " *:?= *(\\d+) *\\{product\\} *";
50
51  public static void testDefaultValue()  throws Exception {
52    ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
53      "-XX:+UnlockExperimentalVMOptions", "-XX:+PrintFlagsFinal", "-version");
54
55    OutputAnalyzer output = new OutputAnalyzer(pb.start());
56    String value = output.firstMatch(printFlagsFinalPattern, 1);
57
58    try {
59      Asserts.assertNotNull(value, "Couldn't find uint flag " + flagName);
60
61      Long longValue = new Long(value);
62
63      // Sanity check that we got a non-zero value.
64      Asserts.assertNotEquals(longValue, "0");
65
66      output.shouldHaveExitValue(0);
67    } catch (Exception e) {
68      System.err.println(output.getOutput());
69      throw e;
70    }
71  }
72
73  public static void testFlags() throws Exception {
74    // For each parallel collector (G1, Parallel, ParNew/CMS)
75    for (String gc : new String[] {"G1", "Parallel", "ConcMarkSweep"}) {
76
77      // Make sure the VM does not allow ParallelGCThreads set to 0
78      String[] flags = new String[] {"-XX:+Use" + gc + "GC", "-XX:ParallelGCThreads=0", "-XX:+PrintFlagsFinal", "-version"};
79      ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(flags);
80      OutputAnalyzer output = new OutputAnalyzer(pb.start());
81      output.shouldHaveExitValue(1);
82
83      // Do some basic testing to ensure the flag updates the count
84      for (long i = 1; i <= 3; i++) {
85        flags = new String[] {"-XX:+Use" + gc + "GC", "-XX:ParallelGCThreads=" + i, "-XX:+PrintFlagsFinal", "-version"};
86        long count = getParallelGCThreadCount(flags);
87        Asserts.assertEQ(count, i, "Specifying ParallelGCThreads=" + i + " for " + gc + "GC does not set the thread count properly!");
88      }
89    }
90
91    // 4294967295 == (unsigned int) -1
92    // So setting ParallelGCThreads=4294967295 should give back 4294967295
93    // and setting ParallelGCThreads=4294967296 should give back 0. (SerialGC is ok with ParallelGCThreads=0)
94    for (long i = 4294967295L; i <= 4294967296L; i++) {
95      String[] flags = new String[] {"-XX:+UseSerialGC", "-XX:ParallelGCThreads=" + i, "-XX:+PrintFlagsFinal", "-version"};
96      long count = getParallelGCThreadCount(flags);
97      Asserts.assertEQ(count, i % 4294967296L, "Specifying ParallelGCThreads=" + i + " does not set the thread count properly!");
98    }
99  }
100
101  public static long getParallelGCThreadCount(String flags[]) throws Exception {
102    ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(flags);
103    OutputAnalyzer output = new OutputAnalyzer(pb.start());
104    output.shouldHaveExitValue(0);
105    String stdout = output.getStdout();
106    return FlagsValue.getFlagLongValue("ParallelGCThreads", stdout);
107  }
108}
109