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 *

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 * version 2 for more details (a copy is included in the LICENSE file that

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 *

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 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

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import java.io.File;

import java.util.ArrayList;

/*

 * @test

 * @bug 6515172 8148766

 * @summary Check that availableProcessors reports the correct value when running in a cpuset on linux

 * @requires os.family == "linux"

 * @modules java.base/jdk.internal.misc

 * @run driver AvailableProcessors

 */

public class AvailableProcessors {

    static final String SUCCESS_STRING = "Found expected processors: ";

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

        if (args.length > 0)

            checkProcessors(Integer.parseInt(args[0]));

        else {

            // run ourselves under different cpu configurations

            // using the taskset command

            String taskset;

            final String taskset1 = "/bin/taskset";

            final String taskset2 = "/usr/bin/taskset";

            if (new File(taskset1).exists())

                taskset = taskset1;

            else if (new File(taskset2).exists())

                taskset = taskset2;

            else {

                System.out.println("Skipping test: could not find taskset command");

                return;

            }

            int available = Runtime.getRuntime().availableProcessors();

            if (available == 1) {

                System.out.println("Skipping test: only one processor available");

                return;

            }

            // Get the java command we want to execute

            // Enable logging for easier failure diagnosis

            ProcessBuilder master =

                    ProcessTools.createJavaProcessBuilder(false,

                                                          "-Xlog:os=trace",

                                                          "AvailableProcessors");

            int[] expected = new int[] { 1, available/2, available-1, available };

            for (int i : expected) {

                System.out.println("Testing for " + i + " processors ...");

                int max = i - 1;

                ArrayList<String> cmdline = new ArrayList<>(master.command());

                // prepend taskset command

                cmdline.add(0, "0-" + max);

                cmdline.add(0, "-c");

                cmdline.add(0, taskset);

                // append expected processor count

                cmdline.add(String.valueOf(i));

                ProcessBuilder pb = new ProcessBuilder(cmdline);

                System.out.println("Final command line: " +

                                   ProcessTools.getCommandLine(pb));

                OutputAnalyzer output = ProcessTools.executeProcess(pb);

                output.shouldContain(SUCCESS_STRING);

            }

        }

    }

    static void checkProcessors(int expected) {

        int available = Runtime.getRuntime().availableProcessors();

        // available can dynamically drop below expected due to aggressive power management

        // but we should never have more than expected, else taskset is broken

        if (available <= 0 || available > expected)

            throw new Error("Expected " + expected + " processors, but found "

                            + available);

        else

            System.out.println(SUCCESS_STRING + available);

    }

}