test/compiler/loopopts/UseCountedLoopSafepoints.java

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/**
 * @test
 * @bug 6869327
 * @summary Test that C2 flag UseCountedLoopSafepoints ensures a safepoint is kept in a CountedLoop
 * @library /testlibrary
 * @run main UseCountedLoopSafepoints
 */

import java.util.concurrent.atomic.AtomicLong;
import com.oracle.java.testlibrary.ProcessTools;
import com.oracle.java.testlibrary.OutputAnalyzer;

public class UseCountedLoopSafepoints {
    private static final AtomicLong _num = new AtomicLong(0);

    // Uses the fact that an EnableBiasedLocking vmop will be started
    // after 500ms, while we are still in the loop. If there is a
    // safepoint in the counted loop, then we will reach safepoint
    // very quickly. Otherwise SafepointTimeout will be hit.
    public static void main (String args[]) throws Exception {
        if (args.length == 1) {
            final int loops = Integer.parseInt(args[0]);
            for (int i = 0; i < loops; i++) {
                _num.addAndGet(1);
            }
        } else {
            ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
                    "-XX:+IgnoreUnrecognizedVMOptions",
                    "-XX:-TieredCompilation",
                    "-XX:+UseBiasedLocking",
                    "-XX:BiasedLockingStartupDelay=500",
                    "-XX:+SafepointTimeout",
                    "-XX:SafepointTimeoutDelay=2000",
                    "-XX:+UseCountedLoopSafepoints",
                    "UseCountedLoopSafepoints",
                    "2000000000"
                    );
            OutputAnalyzer output = new OutputAnalyzer(pb.start());
            output.shouldNotContain("Timeout detected");
            output.shouldHaveExitValue(0);
        }
    }
}