8014659: NPG: performance counters for compressed klass space

Reviewed-by: mgerdin, coleenp, hseigel, jmasa, ctornqvi

hotspot/test/testlibrary/com/oracle/java/testlibrary/Asserts.java

@@ -0,0 +1,395 @@
+/*
+ * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package com.oracle.java.testlibrary;
+
+/**
+ * Asserts that can be used for verifying assumptions in tests.
+ *
+ * An assertion will throw a {@link RuntimeException} if the assertion isn't
+ * valid.  All the asserts can be imported into a test by using a static
+ * import:
+ *
+ * <pre>
+ * {@code
+ * import static com.oracle.java.testlibrary.Asserts.*;
+ * }
+ *
+ * Always provide a message describing the assumption if the line number of the
+ * failing assertion isn't enough to understand why the assumption failed. For
+ * example, if the assertion is in a loop or in a method that is called
+ * multiple times, then the line number won't provide enough context to
+ * understand the failure.
+ * </pre>
+ */
+public class Asserts {
+
+    /**
+     * Shorthand for {@link #assertLessThan(T, T)}.
+     *
+     * @see #assertLessThan(T, T)
+     */
+    public static <T extends Comparable<T>> void assertLT(T lhs, T rhs) {
+        assertLessThan(lhs, rhs);
+    }
+
+    /**
+     * Shorthand for {@link #assertLessThan(T, T, String)}.
+     *
+     * @see #assertLessThan(T, T, String)
+     */
+    public static <T extends Comparable<T>> void assertLT(T lhs, T rhs, String msg) {
+        assertLessThan(lhs, rhs, msg);
+    }
+
+    /**
+     * Calls {@link #assertLessThan(T, T, String)} with a default message.
+     *
+     * @see #assertLessThan(T, T, String)
+     */
+    public static <T extends Comparable<T>> void assertLessThan(T lhs, T rhs) {
+        String msg = "Expected that " + format(lhs) + " < " + format(rhs);
+        assertLessThan(lhs, rhs, msg);
+    }
+
+    /**
+     * Asserts that {@code lhs} is less than {@code rhs}.
+     *
+     * @param lhs The left hand side of the comparison.
+     * @param rhs The right hand side of the comparison.
+     * @param msg A description of the assumption.
+     * @throws RuntimeException if the assertion isn't valid.
+     */
+    public static <T extends Comparable<T>>void assertLessThan(T lhs, T rhs, String msg) {
+        assertTrue(compare(lhs, rhs, msg) < 0, msg);
+    }
+
+    /**
+     * Shorthand for {@link #assertLessThanOrEqual(T, T)}.
+     *
+     * @see #assertLessThanOrEqual(T, T)
+     */
+    public static <T extends Comparable<T>> void assertLTE(T lhs, T rhs) {
+        assertLessThanOrEqual(lhs, rhs);
+    }
+
+    /**
+     * Shorthand for {@link #assertLessThanOrEqual(T, T, String)}.
+     *
+     * @see #assertLessThanOrEqual(T, T, String)
+     */
+    public static <T extends Comparable<T>> void assertLTE(T lhs, T rhs, String msg) {
+        assertLessThanOrEqual(lhs, rhs, msg);
+    }
+
+    /**
+     * Calls {@link #assertLessThanOrEqual(T, T, String)} with a default message.
+     *
+     * @see #assertLessThanOrEqual(T, T, String)
+     */
+    public static <T extends Comparable<T>> void assertLessThanOrEqual(T lhs, T rhs) {
+        String msg = "Expected that " + format(lhs) + " <= " + format(rhs);
+        assertLessThanOrEqual(lhs, rhs, msg);
+    }
+
+    /**
+     * Asserts that {@code lhs} is less than or equal to {@code rhs}.
+     *
+     * @param lhs The left hand side of the comparison.
+     * @param rhs The right hand side of the comparison.
+     * @param msg A description of the assumption.
+     * @throws RuntimeException if the assertion isn't valid.
+     */
+    public static <T extends Comparable<T>> void assertLessThanOrEqual(T lhs, T rhs, String msg) {
+        assertTrue(compare(lhs, rhs, msg) <= 0, msg);
+    }
+
+    /**
+     * Shorthand for {@link #assertEquals(T, T)}.
+     *
+     * @see #assertEquals(T, T)
+     */
+    public static void assertEQ(Object lhs, Object rhs) {
+        assertEquals(lhs, rhs);
+    }
+
+    /**
+     * Shorthand for {@link #assertEquals(T, T, String)}.
+     *
+     * @see #assertEquals(T, T, String)
+     */
+    public static void assertEQ(Object lhs, Object rhs, String msg) {
+        assertEquals(lhs, rhs, msg);
+    }
+
+    /**
+     * Calls {@link #assertEquals(T, T, String)} with a default message.
+     *
+     * @see #assertEquals(T, T, String)
+     */
+    public static void assertEquals(Object lhs, Object rhs) {
+        String msg = "Expected " + format(lhs) + " to equal " + format(rhs);
+        assertEquals(lhs, rhs, msg);
+    }
+
+    /**
+     * Asserts that {@code lhs} is equal to {@code rhs}.
+     *
+     * @param lhs The left hand side of the comparison.
+     * @param rhs The right hand side of the comparison.
+     * @param msg A description of the assumption.
+     * @throws RuntimeException if the assertion isn't valid.
+     */
+    public static void assertEquals(Object lhs, Object rhs, String msg) {
+        if (lhs == null) {
+            if (rhs != null) {
+                error(msg);
+            }
+        } else {
+            assertTrue(lhs.equals(rhs), msg);
+        }
+    }
+
+    /**
+     * Shorthand for {@link #assertGreaterThanOrEqual(T, T)}.
+     *
+     * @see #assertGreaterThanOrEqual(T, T)
+     */
+    public static <T extends Comparable<T>> void assertGTE(T lhs, T rhs) {
+        assertGreaterThanOrEqual(lhs, rhs);
+    }
+
+    /**
+     * Shorthand for {@link #assertGreaterThanOrEqual(T, T, String)}.
+     *
+     * @see #assertGreaterThanOrEqual(T, T, String)
+     */
+    public static <T extends Comparable<T>> void assertGTE(T lhs, T rhs, String msg) {
+        assertGreaterThanOrEqual(lhs, rhs, msg);
+    }
+
+    /**
+     * Calls {@link #assertGreaterThanOrEqual(T, T, String)} with a default message.
+     *
+     * @see #assertGreaterThanOrEqual(T, T, String)
+     */
+    public static <T extends Comparable<T>> void assertGreaterThanOrEqual(T lhs, T rhs) {
+        String msg = "Expected that " + format(lhs) + " >= " + format(rhs);
+        assertGreaterThanOrEqual(lhs, rhs, msg);
+    }
+
+    /**
+     * Asserts that {@code lhs} is greater than or equal to {@code rhs}.
+     *
+     * @param lhs The left hand side of the comparison.
+     * @param rhs The right hand side of the comparison.
+     * @param msg A description of the assumption.
+     * @throws RuntimeException if the assertion isn't valid.
+     */
+    public static <T extends Comparable<T>> void assertGreaterThanOrEqual(T lhs, T rhs, String msg) {
+        assertTrue(compare(lhs, rhs, msg) >= 0, msg);
+    }
+
+    /**
+     * Shorthand for {@link #assertGreaterThan(T, T)}.
+     *
+     * @see #assertGreaterThan(T, T)
+     */
+    public static <T extends Comparable<T>> void assertGT(T lhs, T rhs) {
+        assertGreaterThan(lhs, rhs);
+    }
+
+    /**
+     * Shorthand for {@link #assertGreaterThan(T, T, String)}.
+     *
+     * @see #assertGreaterThan(T, T, String)
+     */
+    public static <T extends Comparable<T>> void assertGT(T lhs, T rhs, String msg) {
+        assertGreaterThan(lhs, rhs, msg);
+    }
+
+    /**
+     * Calls {@link #assertGreaterThan(T, T, String)} with a default message.
+     *
+     * @see #assertGreaterThan(T, T, String)
+     */
+    public static <T extends Comparable<T>> void assertGreaterThan(T lhs, T rhs) {
+        String msg = "Expected that " + format(lhs) + " > " + format(rhs);
+        assertGreaterThan(lhs, rhs, msg);
+    }
+
+    /**
+     * Asserts that {@code lhs} is greater than {@code rhs}.
+     *
+     * @param lhs The left hand side of the comparison.
+     * @param rhs The right hand side of the comparison.
+     * @param msg A description of the assumption.
+     * @throws RuntimeException if the assertion isn't valid.
+     */
+    public static <T extends Comparable<T>> void assertGreaterThan(T lhs, T rhs, String msg) {
+        assertTrue(compare(lhs, rhs, msg) > 0, msg);
+    }
+
+    /**
+     * Shorthand for {@link #assertNotEquals(T, T)}.
+     *
+     * @see #assertNotEquals(T, T)
+     */
+    public static void assertNE(Object lhs, Object rhs) {
+        assertNotEquals(lhs, rhs);
+    }
+
+    /**
+     * Shorthand for {@link #assertNotEquals(T, T, String)}.
+     *
+     * @see #assertNotEquals(T, T, String)
+     */
+    public static void assertNE(Object lhs, Object rhs, String msg) {
+        assertNotEquals(lhs, rhs, msg);
+    }
+
+    /**
+     * Calls {@link #assertNotEquals(T, T, String)} with a default message.
+     *
+     * @see #assertNotEquals(T, T, String)
+     */
+    public static void assertNotEquals(Object lhs, Object rhs) {
+        String msg = "Expected " + format(lhs) + " to not equal " + format(rhs);
+        assertNotEquals(lhs, rhs, msg);
+    }
+
+    /**
+     * Asserts that {@code lhs} is not equal to {@code rhs}.
+     *
+     * @param lhs The left hand side of the comparison.
+     * @param rhs The right hand side of the comparison.
+     * @param msg A description of the assumption.
+     * @throws RuntimeException if the assertion isn't valid.
+     */
+    public static void assertNotEquals(Object lhs, Object rhs, String msg) {
+        if (lhs == null) {
+            if (rhs == null) {
+                error(msg);
+            }
+        } else {
+            assertFalse(lhs.equals(rhs), msg);
+        }
+    }
+
+    /**
+     * Calls {@link #assertNull(Object, String)} with a default message.
+     *
+     * @see #assertNull(Object, String)
+     */
+    public static void assertNull(Object o) {
+        assertNull(o, "Expected " + format(o) + " to be null");
+    }
+
+    /**
+     * Asserts that {@code o} is null.
+     *
+     * @param o The reference assumed to be null.
+     * @param msg A description of the assumption.
+     * @throws RuntimeException if the assertion isn't valid.
+     */
+    public static void assertNull(Object o, String msg) {
+        assertEquals(o, null, msg);
+    }
+
+    /**
+     * Calls {@link #assertNotNull(Object, String)} with a default message.
+     *
+     * @see #assertNotNull(Object, String)
+     */
+    public static void assertNotNull(Object o) {
+        assertNotNull(o, "Expected non null reference");
+    }
+
+    /**
+     * Asserts that {@code o} is <i>not</i> null.
+     *
+     * @param o The reference assumed <i>not</i> to be null,
+     * @param msg A description of the assumption.
+     * @throws RuntimeException if the assertion isn't valid.
+     */
+    public static void assertNotNull(Object o, String msg) {
+        assertNotEquals(o, null, msg);
+    }
+
+    /**
+     * Calls {@link #assertFalse(boolean, String)} with a default message.
+     *
+     * @see #assertFalse(boolean, String)
+     */
+    public static void assertFalse(boolean value) {
+        assertFalse(value, "Expected value to be false");
+    }
+
+    /**
+     * Asserts that {@code value} is {@code false}.
+     *
+     * @param value The value assumed to be false.
+     * @param msg A description of the assumption.
+     * @throws RuntimeException if the assertion isn't valid.
+     */
+    public static void assertFalse(boolean value, String msg) {
+        assertTrue(!value, msg);
+    }
+
+    /**
+     * Calls {@link #assertTrue(boolean, String)} with a default message.
+     *
+     * @see #assertTrue(boolean, String)
+     */
+    public static void assertTrue(boolean value) {
+        assertTrue(value, "Expected value to be true");
+    }
+
+    /**
+     * Asserts that {@code value} is {@code true}.
+     *
+     * @param value The value assumed to be true.
+     * @param msg A description of the assumption.
+     * @throws RuntimeException if the assertion isn't valid.
+     */
+    public static void assertTrue(boolean value, String msg) {
+        if (!value) {
+            error(msg);
+        }
+    }
+
+    private static <T extends Comparable<T>> int compare(T lhs, T rhs, String msg) {
+        assertNotNull(lhs, msg);
+        assertNotNull(rhs, msg);
+        return lhs.compareTo(rhs);
+    }
+
+    private static String format(Object o) {
+        return o == null? "null" : o.toString();
+    }
+
+    private static void error(String msg) {
+        throw new RuntimeException(msg);
+    }
+
+}

hotspot/test/testlibrary/com/oracle/java/testlibrary/ByteCodeLoader.java

@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package com.oracle.java.testlibrary;
+
+import java.security.SecureClassLoader;
+
+/**
+ * {@code ByteCodeLoader} can be used for easy loading of byte code already
+ * present in memory.
+ *
+ * {@code InMemoryCompiler} can be used for compiling source code in a string
+ * into byte code, which then can be loaded with {@code ByteCodeLoader}.
+ *
+ * @see InMemoryCompiler
+ */
+public class ByteCodeLoader extends SecureClassLoader {
+    private final String className;
+    private final byte[] byteCode;
+
+    /**
+     * Creates a new {@code ByteCodeLoader} ready to load a class with the
+     * given name and the given byte code.
+     *
+     * @param className The name of the class
+     * @param byteCode The byte code of the class
+     */
+    public ByteCodeLoader(String className, byte[] byteCode) {
+        this.className = className;
+        this.byteCode = byteCode;
+    }
+
+    @Override
+    protected Class<?> findClass(String name) throws ClassNotFoundException {
+        if (!name.equals(className)) {
+            throw new ClassNotFoundException(name);
+        }
+
+        return defineClass(name, byteCode, 0, byteCode.length);
+    }
+
+    /**
+     * Utility method for creating a new {@code ByteCodeLoader} and then
+     * directly load the given byte code.
+     *
+     * @param className The name of the class
+     * @param byteCode The byte code for the class
+     * @throws ClassNotFoundException if the class can't be loaded
+     * @return A {@see Class} object representing the class
+     */
+    public static Class<?> load(String className, byte[] byteCode) throws ClassNotFoundException {
+        return new ByteCodeLoader(className, byteCode).loadClass(className);
+    }
+}

hotspot/test/testlibrary/com/oracle/java/testlibrary/InMemoryJavaCompiler.java

@@ -0,0 +1,154 @@
+/*
+ * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package com.oracle.java.testlibrary;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+
+import java.net.URI;
+import java.util.Arrays;
+
+import javax.tools.ForwardingJavaFileManager;
+import javax.tools.ForwardingJavaFileManager;
+import javax.tools.FileObject;
+import javax.tools.JavaCompiler;
+import javax.tools.JavaCompiler.CompilationTask;
+import javax.tools.JavaFileManager;
+import javax.tools.JavaFileObject;
+import javax.tools.JavaFileObject.Kind;
+import javax.tools.SimpleJavaFileObject;
+import javax.tools.ToolProvider;
+
+/**
+ * {@code InMemoryJavaCompiler} can be used for compiling a {@link
+ * CharSequence} to a {@code byte[]}.
+ *
+ * The compiler will not use the file system at all, instead using a {@link
+ * ByteArrayOutputStream} for storing the byte code. For the source code, any
+ * kind of {@link CharSequence} can be used, e.g. {@link String}, {@link
+ * StringBuffer} or {@link StringBuilder}.
+ *
+ * The {@code InMemoryCompiler} can easily be used together with a {@code
+ * ByteClassLoader} to easily compile and load source code in a {@link String}:
+ *
+ * <pre>
+ * {@code
+ * import com.oracle.java.testlibrary.InMemoryJavaCompiler;
+ * import com.oracle.java.testlibrary.ByteClassLoader;
+ *
+ * class Example {
+ *     public static void main(String[] args) {
+ *         String className = "Foo";
+ *         String sourceCode = "public class " + className + " {" +
+ *                             "    public void bar() {" +
+ *                             "        System.out.println("Hello from bar!");" +
+ *                             "    }" +
+ *                             "}";
+ *         byte[] byteCode = InMemoryJavaCompiler.compile(className, sourceCode);
+ *         Class fooClass = ByteClassLoader.load(className, byteCode);
+ *     }
+ * }
+ * }
+ * </pre>
+ */
+public class InMemoryJavaCompiler {
+    private static class MemoryJavaFileObject extends SimpleJavaFileObject {
+        private final String className;
+        private final CharSequence sourceCode;
+        private final ByteArrayOutputStream byteCode;
+
+        public MemoryJavaFileObject(String className, CharSequence sourceCode) {
+            super(URI.create("string:///" + className.replace('.','/') + Kind.SOURCE.extension), Kind.SOURCE);
+            this.className = className;
+            this.sourceCode = sourceCode;
+            this.byteCode = new ByteArrayOutputStream();
+        }
+
+        @Override
+        public CharSequence getCharContent(boolean ignoreEncodingErrors) {
+            return sourceCode;
+        }
+
+        @Override
+        public OutputStream openOutputStream() throws IOException {
+            return byteCode;
+        }
+
+        public byte[] getByteCode() {
+            return byteCode.toByteArray();
+        }
+
+        public String getClassName() {
+            return className;
+        }
+    }
+
+    private static class FileManagerWrapper extends ForwardingJavaFileManager {
+        private MemoryJavaFileObject file;
+
+        public FileManagerWrapper(MemoryJavaFileObject file) {
+            super(getCompiler().getStandardFileManager(null, null, null));
+            this.file = file;
+        }
+
+        @Override
+        public JavaFileObject getJavaFileForOutput(Location location, String className,
+                                                   Kind kind, FileObject sibling)
+            throws IOException {
+            if (!file.getClassName().equals(className)) {
+                throw new IOException("Expected class with name " + file.getClassName() +
+                                      ", but got " + className);
+            }
+            return file;
+        }
+    }
+
+    /**
+     * Compiles the class with the given name and source code.
+     *
+     * @param className The name of the class
+     * @param sourceCode The source code for the class with name {@code className}
+     * @throws RuntimeException if the compilation did not succeed
+     * @return The resulting byte code from the compilation
+     */
+    public static byte[] compile(String className, CharSequence sourceCode) {
+        MemoryJavaFileObject file = new MemoryJavaFileObject(className, sourceCode);
+        CompilationTask task = getCompilationTask(file);
+
+        if(!task.call()) {
+            throw new RuntimeException("Could not compile " + className + " with source code " + sourceCode);
+        }
+
+        return file.getByteCode();
+    }
+
+    private static JavaCompiler getCompiler() {
+        return ToolProvider.getSystemJavaCompiler();
+    }
+
+    private static CompilationTask getCompilationTask(MemoryJavaFileObject file) {
+        return getCompiler().getTask(null, new FileManagerWrapper(file), null, null, null, Arrays.asList(file));
+    }
+}

hotspot/test/testlibrary/com/oracle/java/testlibrary/InputArguments.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package com.oracle.java.testlibrary;
+
+import java.lang.management.RuntimeMXBean;
+import java.lang.management.ManagementFactory;
+import java.util.List;
+
+/**
+ * This class provides access to the input arguments to the VM.
+ */
+public class InputArguments {
+    private static final List<String> args;
+
+    static {
+        RuntimeMXBean runtimeMxBean = ManagementFactory.getRuntimeMXBean();
+        args = runtimeMxBean.getInputArguments();
+    }
+
+    /**
+     * Returns true if {@code arg} is an input argument to the VM.
+     *
+     * @param arg The name of the argument.
+     * @return {@code true} if the given argument is an input argument,
+     *         otherwise {@code false}.
+     */
+    public static boolean contains(String arg) {
+        return args.contains(arg);
+    }
+}

hotspot/test/testlibrary/com/oracle/java/testlibrary/PerfCounter.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package com.oracle.java.testlibrary;
+
+import sun.jvmstat.monitor.Monitor;
+
+/**
+ * Represents a performance counter in the JVM.
+ *
+ * See http://openjdk.java.net/groups/hotspot/docs/Serviceability.html#bjvmstat
+ * for more details about performance counters.
+ */
+public class PerfCounter {
+    private final Monitor monitor;
+    private final String name;
+
+    PerfCounter(Monitor monitor, String name) {
+        this.monitor = monitor;
+        this.name = name;
+    }
+
+    /**
+     * Returns the value of this performance counter as a long.
+     *
+     * @return The long value of this performance counter
+     * @throws RuntimeException If the value of the performance counter isn't a long
+     */
+    public long longValue() {
+        Object value = monitor.getValue();
+        if (value instanceof Long) {
+            return ((Long) value).longValue();
+        }
+        throw new RuntimeException("Expected " + monitor.getName() + " to have a long value");
+    }
+
+    /**
+     * Returns the name of the performance counter.
+     *
+     * @return The name of the performance counter.
+     */
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public String toString() {
+        return name;
+    }
+}

hotspot/test/testlibrary/com/oracle/java/testlibrary/PerfCounters.java

@@ -0,0 +1,69 @@
+/*
+ * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package com.oracle.java.testlibrary;
+
+import sun.jvmstat.monitor.Monitor;
+import sun.jvmstat.monitor.MonitorException;
+import sun.jvmstat.monitor.MonitoredHost;
+import sun.jvmstat.monitor.MonitoredVm;
+import sun.jvmstat.monitor.VmIdentifier;
+
+/**
+ * PerfCounters can be used to get a performance counter from the currently
+ * executing VM.
+ *
+ * Throws a runtime exception if an error occurs while communicating with the
+ * currently executing VM.
+ */
+public class PerfCounters {
+    private final static MonitoredVm vm;
+
+    static {
+        try {
+            String pid = Integer.toString(ProcessTools.getProcessId());
+            VmIdentifier vmId = new VmIdentifier(pid);
+            MonitoredHost host = MonitoredHost.getMonitoredHost(vmId);
+            vm = host.getMonitoredVm(vmId);
+        } catch (Exception e) {
+            throw new RuntimeException("Could not connect to the VM");
+        }
+    }
+
+    /**
+     * Returns the performance counter with the given name.
+     *
+     * @param name The name of the performance counter.
+     * @throws IllegalArgumentException If no counter with the given name exists.
+     * @throws MonitorException If an error occurs while communicating with the VM.
+     * @return The performance counter with the given name.
+     */
+    public static PerfCounter findByName(String name)
+        throws MonitorException, IllegalArgumentException {
+        Monitor m = vm.findByName(name);
+        if (m == null) {
+            throw new IllegalArgumentException("Did not find a performance counter with name " + name);
+        }
+        return new PerfCounter(m, name);
+    }
+}