GcCapacityTest.java

/*
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import utils.*;

/*
 * @test
 * @summary Test checks the consistency of the output
 * displayed with jstat -gccapacity.
 * @requires vm.gc != "Z" & vm.gc != "Shenandoah"
 * @modules java.base/jdk.internal.misc
 * @library /test/lib
 * @library ../share
 * @requires vm.opt.ExplicitGCInvokesConcurrent != true
 * @run main/othervm -XX:+UsePerfData -Xmx128M GcCapacityTest
 */
public class GcCapacityTest {

    public static void main(String[] args) throws Exception {

        // We will be running "jstat -gc" tool
        JstatGcCapacityTool jstatGcTool = new JstatGcCapacityTool(ProcessHandle.current().pid());

        // Run once and get the  results asserting that they are reasonable
        JstatGcCapacityResults measurement1 = jstatGcTool.measure();
        measurement1.assertConsistency();

        // Provoke a gc and verify the changed values
        GcProvoker gcProvoker = new GcProvoker();
        gcProvoker.provokeGc();
        JstatGcCapacityResults measurement2 = jstatGcTool.measure();
        measurement2.assertConsistency();

        // Assert that the GC events count has increased
        JstatResults.assertGCEventsIncreased(measurement1, measurement2);

        // Provoke a gc again and verify the changed values
        gcProvoker.provokeGc();
        JstatGcCapacityResults measurement3 = jstatGcTool.measure();
        measurement3.assertConsistency();

        // Assert that the GC events count has increased
        JstatResults.assertGCEventsIncreased(measurement1, measurement2);
    }

}