- * In addition, this class provides methods to create instrumentation
- * objects in the instrumentation buffer for the Java virtual machine
- * that is running these methods. It also contains methods for acquiring
- * the value of a platform specific high resolution clock for time
- * stamp and interval measurement purposes.
- *
- * @author Brian Doherty
- * @since 1.4.2
- * @see #getPerf
- * @see sun.misc.Perf$GetPerfAction
- * @see java.nio.ByteBuffer
- */
-public final class Perf {
-
- private static Perf instance;
-
- private static final int PERF_MODE_RO = 0;
- private static final int PERF_MODE_RW = 1;
-
- private Perf() { } // prevent instantiation
-
- /**
- * The GetPerfAction class is a convenience class for acquiring access
- * to the singleton Perf instance using the
- * AccessController.doPrivileged() method.
- *
- * An instance of this class can be used as the argument to
- * AccessController.doPrivileged(PrivilegedAction).
- *
Here is a suggested idiom for use of this class: - * - *
{@code
- * class MyTrustedClass {
- * private static final Perf perf =
- * AccessController.doPrivileged(new Perf.GetPerfAction());
- * ...
- * }
- * }
- * In the presence of a security manager, the MyTrustedClass
- * class in the above example will need to be granted the
- * "sun.misc.Perf.getPerf" RuntimePermission
- * permission in order to successfully acquire the singleton Perf instance.
- *
- * Please note that the "sun.misc.Perf.getPerf" permission
- * is not a JDK specified permission.
- *
- * @see java.security.AccessController#doPrivileged(PrivilegedAction)
- * @see java.lang.RuntimePermission
- */
- public static class GetPerfAction implements PrivilegedAction
- * The getPerf() method returns the singleton instance of the Perf
- * class. The returned object provides the caller with the capability
- * for accessing the instrumentation buffer for this or another local
- * Java virtual machine.
- *
- * If a security manager is installed, its
- * Access to the returned
- * Please note that the "sun.misc.Perf.getPerf" permission
- * is not a JDK specified permission.
- *
- * @return A reference to the singleton Perf instance.
- * @throws AccessControlException if a security manager exists and
- * its
- * This method will attach to the instrumentation buffer for the
- * specified virtual machine. It returns a
- * If the
- * If the
- * The attach mode specifies the access permissions requested for the
- * instrumentation buffer of the target virtual machine. The permitted
- * access permissions are:
- *
- * This method behaves just as the
- * This method calls into the Java virtual machine to perform the platform
- * specific attach method. Buffers returned from this method are
- * internally managed as
- * The implementation of this method may return distinct or identical
- *
- * For the Sun HotSpot JVM, two distinct calls to attach to the same
- * target Java virtual machine will result in two distinct ByteBuffer
- * objects returned by this method. This may change in a future release.
- *
- * @param user A
- * If this method is passed a
- * If this method is passed a
- * Access to the instrument is provided through the returned
- * The maximum length of the
- * The underlying implementation may further limit the length of the
- * value, but will continue to preserve the null terminator.
- *
- * Access to the instrument is provided through the returned
- * The maximum length of the
- * The underlying implementation may further limit the length of the
- * initial or subsequent value, but will continue to preserve the null
- * terminator.
- *
- * Access to the instrument is provided through the returned
- * The
- * The underlying implementation may further limit the length of the
- * length of the initial or subsequent value.
- *
- * Access to the instrument is provided through the returned
+ * In addition, this class provides methods to create instrumentation
+ * objects in the instrumentation buffer for the Java virtual machine
+ * that is running these methods. It also contains methods for acquiring
+ * the value of a platform specific high resolution clock for time
+ * stamp and interval measurement purposes.
+ *
+ * @author Brian Doherty
+ * @since 1.4.2
+ * @see #getPerf
+ * @see jdk.internal.perf.Perf.GetPerfAction
+ * @see java.nio.ByteBuffer
+ */
+public final class Perf {
+
+ private static Perf instance;
+
+ private static final int PERF_MODE_RO = 0;
+ private static final int PERF_MODE_RW = 1;
+
+ private Perf() { } // prevent instantiation
+
+ /**
+ * The GetPerfAction class is a convenience class for acquiring access
+ * to the singleton Perf instance using the
+ *
+ * An instance of this class can be used as the argument to
+ * Here is a suggested idiom for use of this class:
+ *
+ *
+ * In the presence of a security manager, the
+ * Please note that the "sun.misc.Perf.getPerf" permission
+ * is not a JDK specified permission.
+ *
+ * @see java.security.AccessController#doPrivileged(PrivilegedAction)
+ * @see java.lang.RuntimePermission
+ */
+ public static class GetPerfAction implements PrivilegedAction
+ * The getPerf() method returns the singleton instance of the Perf
+ * class. The returned object provides the caller with the capability
+ * for accessing the instrumentation buffer for this or another local
+ * Java virtual machine.
+ *
+ * If a security manager is installed, its
+ * Access to the returned
+ * Please note that the "sun.misc.Perf.getPerf" permission
+ * is not a JDK specified permission.
+ *
+ * @return A reference to the singleton Perf instance.
+ * @throws SecurityException if a security manager exists and its
+ *
+ * This method will attach to the instrumentation buffer for the
+ * specified virtual machine. It returns a
+ * If the
+ * If the
+ * The attach mode specifies the access permissions requested for the
+ * instrumentation buffer of the target virtual machine. The permitted
+ * access permissions are:
+ *
+ * This method behaves just as the
+ * This method calls into the Java virtual machine to perform the platform
+ * specific attach method. Buffers returned from this method are
+ * internally managed as
+ * The implementation of this method may return distinct or identical
+ *
+ * For the Sun HotSpot JVM, two distinct calls to attach to the same
+ * target Java virtual machine will result in two distinct ByteBuffer
+ * objects returned by this method. This may change in a future release.
+ *
+ * @param user A
+ * If this method is passed a
+ * If this method is passed a
+ * Access to the instrument is provided through the returned
+ * The maximum length of the
+ * The underlying implementation may further limit the length of the
+ * value, but will continue to preserve the null terminator.
+ *
+ * Access to the instrument is provided through the returned
+ * The maximum length of the
+ * The underlying implementation may further limit the length of the
+ * initial or subsequent value, but will continue to preserve the null
+ * terminator.
+ *
+ * Access to the instrument is provided through the returned
+ * The
+ * The underlying implementation may further limit the length of the
+ * length of the initial or subsequent value.
+ *
+ * Access to the instrument is provided through the returned Perf.getPerf() method in a privileged context.
- *
- * @see #getPerf
- */
- public Perf run() {
- return getPerf();
- }
- }
-
- /**
- * Return a reference to the singleton Perf instance.
- * checkPermission
- * method is called with a RuntimePermission with a target
- * of "sun.misc.Perf.getPerf". A security exception will result
- * if the caller has not been granted this permission.
- * Perf object should be protected
- * by its caller and not passed on to untrusted code. This object can
- * be used to attach to the instrumentation buffer provided by this Java
- * virtual machine or for those of other Java virtual machines running
- * on the same system. The instrumentation buffer may contain senstitive
- * information. API's built on top of this interface may want to provide
- * finer grained access control to the contents of individual
- * instrumentation objects contained within the buffer.
- * checkPermission method doesn't allow
- * access to the "sun.misc.Perf.getPerf" target.
- * @see java.lang.RuntimePermission
- * @see #attach
- */
- public static Perf getPerf()
- {
- SecurityManager security = System.getSecurityManager();
- if (security != null) {
- Permission perm = new RuntimePermission("sun.misc.Perf.getPerf");
- security.checkPermission(perm);
- }
-
- return instance;
- }
-
- /**
- * Attach to the instrumentation buffer for the specified Java virtual
- * machine.
- * ByteBuffer object
- * that is initialized to access the instrumentation buffer for the
- * indicated Java virtual machine. The lvmid parameter is
- * a integer value that uniquely identifies the target local Java virtual
- * machine. It is typically, but not necessarily, the process id of
- * the target Java virtual machine.
- * lvmid identifies a Java virtual machine different
- * from the one running this method, then the coherency characteristics
- * of the buffer are implementation dependent. Implementations that do
- * not support named, coherent, shared memory may return a
- * ByteBuffer object that contains only a snap shot of the
- * data in the instrumentation buffer. Implementations that support named,
- * coherent, shared memory, may return a ByteBuffer object
- * that will be changing dynamically over time as the target Java virtual
- * machine updates its mapping of this buffer.
- * lvmid is 0 or equal to the actual lvmid
- * for the Java virtual machine running this method, then the returned
- * ByteBuffer object will always be coherent and dynamically
- * changing.
- *
- *
- *
- * @param lvmid an integer that uniquely identifies the
- * target local Java virtual machine.
- * @param mode a string indicating the attach mode.
- * @return ByteBuffer a direct allocated byte buffer
- * @throws IllegalArgumentException The lvmid or mode was invalid.
- * @throws IOException An I/O error occurred while trying to acquire
- * the instrumentation buffer.
- * @throws OutOfMemoryError The instrumentation buffer could not be mapped
- * into the virtual machine's address space.
- * @see java.nio.ByteBuffer
- */
- public ByteBuffer attach(int lvmid, String mode)
- throws IllegalArgumentException, IOException
- {
- if (mode.compareTo("r") == 0) {
- return attachImpl(null, lvmid, PERF_MODE_RO);
- }
- else if (mode.compareTo("rw") == 0) {
- return attachImpl(null, lvmid, PERF_MODE_RW);
- }
- else {
- throw new IllegalArgumentException("unknown mode");
- }
- }
-
- /**
- * Attach to the instrumentation buffer for the specified Java virtual
- * machine owned by the given user.
- * attach(int lvmid, String mode)
- * method, except that it only searches for Java virtual machines
- * owned by the specified user.
- *
- * @param user A String object containing the
- * name of the user that owns the target Java
- * virtual machine.
- * @param lvmid an integer that uniquely identifies the
- * target local Java virtual machine.
- * @param mode a string indicating the attach mode.
- * @return ByteBuffer a direct allocated byte buffer
- * @throws IllegalArgumentException The lvmid or mode was invalid.
- * @throws IOException An I/O error occurred while trying to acquire
- * the instrumentation buffer.
- * @throws OutOfMemoryError The instrumentation buffer could not be mapped
- * into the virtual machine's address space.
- * @see java.nio.ByteBuffer
- */
- public ByteBuffer attach(String user, int lvmid, String mode)
- throws IllegalArgumentException, IOException
- {
- if (mode.compareTo("r") == 0) {
- return attachImpl(user, lvmid, PERF_MODE_RO);
- }
- else if (mode.compareTo("rw") == 0) {
- return attachImpl(user, lvmid, PERF_MODE_RW);
- }
- else {
- throw new IllegalArgumentException("unknown mode");
- }
- }
-
- /**
- * Call the implementation specific attach method.
- * PhantomRefereces to provide for
- * guaranteed, secure release of the native resources.
- *
- * @param user A String object containing the
- * name of the user that owns the target Java
- * virtual machine.
- * @param lvmid an integer that uniquely identifies the
- * target local Java virtual machine.
- * @param mode a string indicating the attach mode.
- * @return ByteBuffer a direct allocated byte buffer
- * @throws IllegalArgumentException The lvmid or mode was invalid.
- * @throws IOException An I/O error occurred while trying to acquire
- * the instrumentation buffer.
- * @throws OutOfMemoryError The instrumentation buffer could not be mapped
- * into the virtual machine's address space.
- */
- private ByteBuffer attachImpl(String user, int lvmid, int mode)
- throws IllegalArgumentException, IOException
- {
- final ByteBuffer b = attach(user, lvmid, mode);
-
- if (lvmid == 0) {
- // The native instrumentation buffer for this Java virtual
- // machine is never unmapped.
- return b;
- }
- else {
- // This is an instrumentation buffer for another Java virtual
- // machine with native resources that need to be managed. We
- // create a duplicate of the native ByteBuffer and manage it
- // with a Cleaner object (PhantomReference). When the duplicate
- // becomes only phantomly reachable, the native resources will
- // be released.
-
- final ByteBuffer dup = b.duplicate();
- Cleaner.create(dup, new Runnable() {
- public void run() {
- try {
- instance.detach(b);
- }
- catch (Throwable th) {
- // avoid crashing the reference handler thread,
- // but provide for some diagnosability
- assert false : th.toString();
- }
- }
- });
- return dup;
- }
- }
-
- /**
- * Native method to perform the implementation specific attach mechanism.
- * ByteBuffer objects for two distinct calls requesting
- * attachment to the same Java virtual machine.
- * String object containing the
- * name of the user that owns the target Java
- * virtual machine.
- * @param lvmid an integer that uniquely identifies the
- * target local Java virtual machine.
- * @param mode a string indicating the attach mode.
- * @return ByteBuffer a direct allocated byte buffer
- * @throws IllegalArgumentException The lvmid or mode was invalid.
- * @throws IOException An I/O error occurred while trying to acquire
- * the instrumentation buffer.
- * @throws OutOfMemoryError The instrumentation buffer could not be mapped
- * into the virtual machine's address space.
- */
- private native ByteBuffer attach(String user, int lvmid, int mode)
- throws IllegalArgumentException, IOException;
-
- /**
- * Native method to perform the implementation specific detach mechanism.
- * ByteBuffer object that is
- * not created by the attach method, then the results of
- * this method are undefined, with unpredictable and potentially damaging
- * effects to the Java virtual machine. To prevent accidental or malicious
- * use of this method, all native ByteBuffer created by the
- * attach method are managed internally as PhantomReferences
- * and resources are freed by the system.
- * ByteBuffer object created
- * by the attach method with a lvmid for the Java virtual
- * machine running this method (lvmid=0, for example), then the detach
- * request is silently ignored.
- *
- * @param ByteBuffer A direct allocated byte buffer created by the
- * attach method.
- * @see java.nio.ByteBuffer
- * @see #attach
- */
- private native void detach(ByteBuffer bb);
-
- /**
- * Create a long scalar entry in the instrumentation buffer
- * with the given variability characteristic, units, and initial value.
- *
- * ByteBuffer object. Typically, this object should be wrapped
- * with LongBuffer view object.
- *
- * @param variability the variability characteristic for this entry.
- * @param units the units for this entry.
- * @param name the name of this entry.
- * @param value the initial value for this entry.
- * @return ByteBuffer a direct allocated ByteBuffer object that
- * allows write access to a native memory location
- * containing a long value.
- *
- * see sun.misc.perf.Variability
- * see sun.misc.perf.Units
- * @see java.nio.ByteBuffer
- */
- public native ByteBuffer createLong(String name, int variability,
- int units, long value);
-
- /**
- * Create a String entry in the instrumentation buffer with
- * the given variability characteristic, units, and initial value.
- * String stored in this string
- * instrument is given in by maxLength parameter. Updates
- * to this instrument with String values with lengths greater
- * than maxLength will be truncated to maxLength.
- * The truncated value will be terminated by a null character.
- *
- * ByteBuffer object.
- *
- * @param variability the variability characteristic for this entry.
- * @param units the units for this entry.
- * @param name the name of this entry.
- * @param value the initial value for this entry.
- * @param maxLength the maximum string length for this string
- * instrument.
- * @return ByteBuffer a direct allocated ByteBuffer that allows
- * write access to a native memory location
- * containing a long value.
- *
- * see sun.misc.perf.Variability
- * see sun.misc.perf.Units
- * @see java.nio.ByteBuffer
- */
- public ByteBuffer createString(String name, int variability,
- int units, String value, int maxLength)
- {
- byte[] v = getBytes(value);
- byte[] v1 = new byte[v.length+1];
- System.arraycopy(v, 0, v1, 0, v.length);
- v1[v.length] = '\0';
- return createByteArray(name, variability, units, v1, Math.max(v1.length, maxLength));
- }
-
- /**
- * Create a String entry in the instrumentation buffer with
- * the given variability characteristic, units, and initial value.
- * String stored in this string
- * instrument is implied by the length of the value parameter.
- * Subsequent updates to the value of this instrument will be truncated
- * to this implied maximum length. The truncated value will be terminated
- * by a null character.
- *
- * ByteBuffer object.
- *
- * @param variability the variability characteristic for this entry.
- * @param units the units for this entry.
- * @param name the name of this entry.
- * @param value the initial value for this entry.
- * @return ByteBuffer a direct allocated ByteBuffer that allows
- * write access to a native memory location
- * containing a long value.
- *
- * see sun.misc.perf.Variability
- * see sun.misc.perf.Units
- * @see java.nio.ByteBuffer
- */
- public ByteBuffer createString(String name, int variability,
- int units, String value)
- {
- byte[] v = getBytes(value);
- byte[] v1 = new byte[v.length+1];
- System.arraycopy(v, 0, v1, 0, v.length);
- v1[v.length] = '\0';
- return createByteArray(name, variability, units, v1, v1.length);
- }
-
- /**
- * Create a byte vector entry in the instrumentation buffer
- * with the given variability characteristic, units, and initial value.
- * maxLength parameter limits the size of the byte
- * array instrument such that the initial or subsequent updates beyond
- * this length are silently ignored. No special handling of truncated
- * updates is provided.
- *
- * ByteBuffer object.
- *
- * @param variability the variability characteristic for this entry.
- * @param units the units for this entry.
- * @param name the name of this entry.
- * @param value the initial value for this entry.
- * @param maxLength the maximum length of this byte array.
- * @return ByteBuffer a direct allocated byte buffer that allows
- * write access to a native memory location
- * containing a long value.
- *
- * see sun.misc.perf.Variability
- * see sun.misc.perf.Units
- * @see java.nio.ByteBuffer
- */
- public native ByteBuffer createByteArray(String name, int variability,
- int units, byte[] value,
- int maxLength);
-
-
- /**
- * convert string to an array of UTF-8 bytes
- */
- private static byte[] getBytes(String s)
- {
- byte[] bytes = null;
-
- try {
- bytes = s.getBytes("UTF-8");
- }
- catch (UnsupportedEncodingException e) {
- // ignore, UTF-8 encoding is always known
- }
-
- return bytes;
- }
-
- /**
- * Return the value of the High Resolution Counter.
- *
- * The High Resolution Counter returns the number of ticks since
- * since the start of the Java virtual machine. The resolution of
- * the counter is machine dependent and can be determined from the
- * value return by the {@link #highResFrequency} method.
- *
- * @return the number of ticks of machine dependent resolution since
- * the start of the Java virtual machine.
- *
- * @see #highResFrequency
- * @see java.lang.System#currentTimeMillis()
- */
- public native long highResCounter();
-
- /**
- * Returns the frequency of the High Resolution Counter, in ticks per
- * second.
- *
- * This value can be used to convert the value of the High Resolution
- * Counter, as returned from a call to the {@link #highResCounter} method,
- * into the number of seconds since the start of the Java virtual machine.
- *
- * @return the frequency of the High Resolution Counter.
- * @see #highResCounter
- */
- public native long highResFrequency();
-
- private static native void registerNatives();
-
- static {
- registerNatives();
- instance = new Perf();
- }
-}
--- /dev/null 2015-10-21 15:25:26.827416476 +0100
+++ new/src/java.base/share/classes/jdk/internal/perf/Perf.java 2016-01-08 18:52:07.213331880 +0000
@@ -0,0 +1,547 @@
+/*
+ * Copyright (c) 2002, 2006, 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. Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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 jdk.internal.perf;
+
+import java.nio.ByteBuffer;
+import java.security.Permission;
+import java.security.PrivilegedAction;
+import java.io.IOException;
+import java.io.UnsupportedEncodingException;
+import jdk.internal.ref.CleanerFactory;
+
+/**
+ * The Perf class provides the ability to attach to an instrumentation
+ * buffer maintained by a Java virtual machine. The instrumentation
+ * buffer may be for the Java virtual machine running the methods of
+ * this class or it may be for another Java virtual machine on the
+ * same system.
+ * AccessController.doPrivileged() method.
+ * AccessController.doPrivileged(PrivilegedAction).
+ *
+ * {@code
+ * class MyTrustedClass {
+ * private static final Perf perf =
+ * AccessController.doPrivileged(new Perf.GetPerfActionMyTrustedClass
+ * class in the above example will need to be granted the
+ * "sun.misc.Perf.getPerf" RuntimePermission
+ * permission in order to successfully acquire the singleton Perf instance.
+ * Perf.getPerf() method in a privileged context.
+ *
+ * @see #getPerf
+ */
+ public Perf run() {
+ return getPerf();
+ }
+ }
+
+ /**
+ * Return a reference to the singleton Perf instance.
+ * checkPermission
+ * method is called with a RuntimePermission with a target
+ * of "sun.misc.Perf.getPerf". A security exception will result
+ * if the caller has not been granted this permission.
+ * Perf object should be protected
+ * by its caller and not passed on to untrusted code. This object can
+ * be used to attach to the instrumentation buffer provided by this Java
+ * virtual machine or for those of other Java virtual machines running
+ * on the same system. The instrumentation buffer may contain senstitive
+ * information. API's built on top of this interface may want to provide
+ * finer grained access control to the contents of individual
+ * instrumentation objects contained within the buffer.
+ * checkPermission method doesn't allow access
+ * to the "jdk.internal.perf.Perf.getPerf"" target.
+ * @see java.lang.RuntimePermission
+ * @see #attach
+ */
+ public static Perf getPerf()
+ {
+ SecurityManager security = System.getSecurityManager();
+ if (security != null) {
+ Permission perm = new RuntimePermission("jdk.internal.perf.Perf.getPerf");
+ security.checkPermission(perm);
+ }
+
+ return instance;
+ }
+
+ /**
+ * Attach to the instrumentation buffer for the specified Java virtual
+ * machine.
+ * ByteBuffer object
+ * that is initialized to access the instrumentation buffer for the
+ * indicated Java virtual machine. The lvmid parameter is
+ * a integer value that uniquely identifies the target local Java virtual
+ * machine. It is typically, but not necessarily, the process id of
+ * the target Java virtual machine.
+ * lvmid identifies a Java virtual machine different
+ * from the one running this method, then the coherency characteristics
+ * of the buffer are implementation dependent. Implementations that do
+ * not support named, coherent, shared memory may return a
+ * ByteBuffer object that contains only a snap shot of the
+ * data in the instrumentation buffer. Implementations that support named,
+ * coherent, shared memory, may return a ByteBuffer object
+ * that will be changing dynamically over time as the target Java virtual
+ * machine updates its mapping of this buffer.
+ * lvmid is 0 or equal to the actual lvmid
+ * for the Java virtual machine running this method, then the returned
+ * ByteBuffer object will always be coherent and dynamically
+ * changing.
+ *
+ *
+ *
+ * @param lvmid an integer that uniquely identifies the
+ * target local Java virtual machine.
+ * @param mode a string indicating the attach mode.
+ * @return ByteBuffer a direct allocated byte buffer
+ * @throws IllegalArgumentException The lvmid or mode was invalid.
+ * @throws IOException An I/O error occurred while trying to acquire
+ * the instrumentation buffer.
+ * @throws OutOfMemoryError The instrumentation buffer could not be mapped
+ * into the virtual machine's address space.
+ * @see java.nio.ByteBuffer
+ */
+ public ByteBuffer attach(int lvmid, String mode)
+ throws IllegalArgumentException, IOException
+ {
+ if (mode.compareTo("r") == 0) {
+ return attachImpl(null, lvmid, PERF_MODE_RO);
+ }
+ else if (mode.compareTo("rw") == 0) {
+ return attachImpl(null, lvmid, PERF_MODE_RW);
+ }
+ else {
+ throw new IllegalArgumentException("unknown mode");
+ }
+ }
+
+ /**
+ * Attach to the instrumentation buffer for the specified Java virtual
+ * machine owned by the given user.
+ * attach(int lvmid, String mode)
+ * method, except that it only searches for Java virtual machines
+ * owned by the specified user.
+ *
+ * @param user A String object containing the
+ * name of the user that owns the target Java
+ * virtual machine.
+ * @param lvmid an integer that uniquely identifies the
+ * target local Java virtual machine.
+ * @param mode a string indicating the attach mode.
+ * @return ByteBuffer a direct allocated byte buffer
+ * @throws IllegalArgumentException The lvmid or mode was invalid.
+ * @throws IOException An I/O error occurred while trying to acquire
+ * the instrumentation buffer.
+ * @throws OutOfMemoryError The instrumentation buffer could not be mapped
+ * into the virtual machine's address space.
+ * @see java.nio.ByteBuffer
+ */
+ public ByteBuffer attach(String user, int lvmid, String mode)
+ throws IllegalArgumentException, IOException
+ {
+ if (mode.compareTo("r") == 0) {
+ return attachImpl(user, lvmid, PERF_MODE_RO);
+ }
+ else if (mode.compareTo("rw") == 0) {
+ return attachImpl(user, lvmid, PERF_MODE_RW);
+ }
+ else {
+ throw new IllegalArgumentException("unknown mode");
+ }
+ }
+
+ /**
+ * Call the implementation specific attach method.
+ * PhantomRefereces to provide for
+ * guaranteed, secure release of the native resources.
+ *
+ * @param user A String object containing the
+ * name of the user that owns the target Java
+ * virtual machine.
+ * @param lvmid an integer that uniquely identifies the
+ * target local Java virtual machine.
+ * @param mode a string indicating the attach mode.
+ * @return ByteBuffer a direct allocated byte buffer
+ * @throws IllegalArgumentException The lvmid or mode was invalid.
+ * @throws IOException An I/O error occurred while trying to acquire
+ * the instrumentation buffer.
+ * @throws OutOfMemoryError The instrumentation buffer could not be mapped
+ * into the virtual machine's address space.
+ */
+ private ByteBuffer attachImpl(String user, int lvmid, int mode)
+ throws IllegalArgumentException, IOException
+ {
+ final ByteBuffer b = attach(user, lvmid, mode);
+
+ if (lvmid == 0) {
+ // The native instrumentation buffer for this Java virtual
+ // machine is never unmapped.
+ return b;
+ }
+ else {
+ // This is an instrumentation buffer for another Java virtual
+ // machine with native resources that need to be managed. We
+ // create a duplicate of the native ByteBuffer and manage it
+ // with a Cleaner. When the duplicate becomes phantom reachable,
+ // the native resources will be released.
+
+ final ByteBuffer dup = b.duplicate();
+
+ CleanerFactory.cleaner()
+ .register(dup, new CleanerAction(instance, b));
+ return dup;
+ }
+ }
+
+ private static class CleanerAction implements Runnable {
+ private final ByteBuffer bb;
+ private final Perf perf;
+ CleanerAction(Perf perf, ByteBuffer bb) {
+ this.perf = perf;
+ this.bb = bb;
+ }
+ public void run() {
+ try {
+ perf.detach(bb);
+ } catch (Throwable th) {
+ // avoid crashing the reference handler thread,
+ // but provide for some diagnosability
+ assert false : th.toString();
+ }
+ }
+ }
+
+ /**
+ * Native method to perform the implementation specific attach mechanism.
+ * ByteBuffer objects for two distinct calls requesting
+ * attachment to the same Java virtual machine.
+ * String object containing the
+ * name of the user that owns the target Java
+ * virtual machine.
+ * @param lvmid an integer that uniquely identifies the
+ * target local Java virtual machine.
+ * @param mode a string indicating the attach mode.
+ * @return ByteBuffer a direct allocated byte buffer
+ * @throws IllegalArgumentException The lvmid or mode was invalid.
+ * @throws IOException An I/O error occurred while trying to acquire
+ * the instrumentation buffer.
+ * @throws OutOfMemoryError The instrumentation buffer could not be mapped
+ * into the virtual machine's address space.
+ */
+ private native ByteBuffer attach(String user, int lvmid, int mode)
+ throws IllegalArgumentException, IOException;
+
+ /**
+ * Native method to perform the implementation specific detach mechanism.
+ * ByteBuffer object that is
+ * not created by the attach method, then the results of
+ * this method are undefined, with unpredictable and potentially damaging
+ * effects to the Java virtual machine. To prevent accidental or malicious
+ * use of this method, all native ByteBuffer created by the
+ * attach method are managed internally as PhantomReferences
+ * and resources are freed by the system.
+ * ByteBuffer object created
+ * by the attach method with a lvmid for the Java virtual
+ * machine running this method (lvmid=0, for example), then the detach
+ * request is silently ignored.
+ *
+ * @param bb A direct allocated byte buffer created by the
+ * attach method.
+ * @see java.nio.ByteBuffer
+ * @see #attach
+ */
+ private native void detach(ByteBuffer bb);
+
+ /**
+ * Create a long scalar entry in the instrumentation buffer
+ * with the given variability characteristic, units, and initial value.
+ *
+ * ByteBuffer object. Typically, this object should be wrapped
+ * with LongBuffer view object.
+ *
+ * @param variability the variability characteristic for this entry.
+ * @param units the units for this entry.
+ * @param name the name of this entry.
+ * @param value the initial value for this entry.
+ * @return ByteBuffer a direct allocated ByteBuffer object that
+ * allows write access to a native memory location
+ * containing a long value.
+ *
+ * see sun.misc.perf.Variability
+ * see sun.misc.perf.Units
+ * @see java.nio.ByteBuffer
+ */
+ public native ByteBuffer createLong(String name, int variability,
+ int units, long value);
+
+ /**
+ * Create a String entry in the instrumentation buffer with
+ * the given variability characteristic, units, and initial value.
+ * String stored in this string
+ * instrument is given in by maxLength parameter. Updates
+ * to this instrument with String values with lengths greater
+ * than maxLength will be truncated to maxLength.
+ * The truncated value will be terminated by a null character.
+ *
+ * ByteBuffer object.
+ *
+ * @param variability the variability characteristic for this entry.
+ * @param units the units for this entry.
+ * @param name the name of this entry.
+ * @param value the initial value for this entry.
+ * @param maxLength the maximum string length for this string
+ * instrument.
+ * @return ByteBuffer a direct allocated ByteBuffer that allows
+ * write access to a native memory location
+ * containing a long value.
+ *
+ * see sun.misc.perf.Variability
+ * see sun.misc.perf.Units
+ * @see java.nio.ByteBuffer
+ */
+ public ByteBuffer createString(String name, int variability,
+ int units, String value, int maxLength)
+ {
+ byte[] v = getBytes(value);
+ byte[] v1 = new byte[v.length+1];
+ System.arraycopy(v, 0, v1, 0, v.length);
+ v1[v.length] = '\0';
+ return createByteArray(name, variability, units, v1, Math.max(v1.length, maxLength));
+ }
+
+ /**
+ * Create a String entry in the instrumentation buffer with
+ * the given variability characteristic, units, and initial value.
+ * String stored in this string
+ * instrument is implied by the length of the value parameter.
+ * Subsequent updates to the value of this instrument will be truncated
+ * to this implied maximum length. The truncated value will be terminated
+ * by a null character.
+ *
+ * ByteBuffer object.
+ *
+ * @param variability the variability characteristic for this entry.
+ * @param units the units for this entry.
+ * @param name the name of this entry.
+ * @param value the initial value for this entry.
+ * @return ByteBuffer a direct allocated ByteBuffer that allows
+ * write access to a native memory location
+ * containing a long value.
+ *
+ * see sun.misc.perf.Variability
+ * see sun.misc.perf.Units
+ * @see java.nio.ByteBuffer
+ */
+ public ByteBuffer createString(String name, int variability,
+ int units, String value)
+ {
+ byte[] v = getBytes(value);
+ byte[] v1 = new byte[v.length+1];
+ System.arraycopy(v, 0, v1, 0, v.length);
+ v1[v.length] = '\0';
+ return createByteArray(name, variability, units, v1, v1.length);
+ }
+
+ /**
+ * Create a byte vector entry in the instrumentation buffer
+ * with the given variability characteristic, units, and initial value.
+ * maxLength parameter limits the size of the byte
+ * array instrument such that the initial or subsequent updates beyond
+ * this length are silently ignored. No special handling of truncated
+ * updates is provided.
+ *
+ * ByteBuffer object.
+ *
+ * @param variability the variability characteristic for this entry.
+ * @param units the units for this entry.
+ * @param name the name of this entry.
+ * @param value the initial value for this entry.
+ * @param maxLength the maximum length of this byte array.
+ * @return ByteBuffer a direct allocated byte buffer that allows
+ * write access to a native memory location
+ * containing a long value.
+ *
+ * see sun.misc.perf.Variability
+ * see sun.misc.perf.Units
+ * @see java.nio.ByteBuffer
+ */
+ public native ByteBuffer createByteArray(String name, int variability,
+ int units, byte[] value,
+ int maxLength);
+
+
+ /**
+ * convert string to an array of UTF-8 bytes
+ */
+ private static byte[] getBytes(String s)
+ {
+ byte[] bytes = null;
+
+ try {
+ bytes = s.getBytes("UTF-8");
+ }
+ catch (UnsupportedEncodingException e) {
+ // ignore, UTF-8 encoding is always known
+ }
+
+ return bytes;
+ }
+
+ /**
+ * Return the value of the High Resolution Counter.
+ *
+ * The High Resolution Counter returns the number of ticks since
+ * since the start of the Java virtual machine. The resolution of
+ * the counter is machine dependent and can be determined from the
+ * value return by the {@link #highResFrequency} method.
+ *
+ * @return the number of ticks of machine dependent resolution since
+ * the start of the Java virtual machine.
+ *
+ * @see #highResFrequency
+ * @see java.lang.System#currentTimeMillis()
+ */
+ public native long highResCounter();
+
+ /**
+ * Returns the frequency of the High Resolution Counter, in ticks per
+ * second.
+ *
+ * This value can be used to convert the value of the High Resolution
+ * Counter, as returned from a call to the {@link #highResCounter} method,
+ * into the number of seconds since the start of the Java virtual machine.
+ *
+ * @return the frequency of the High Resolution Counter.
+ * @see #highResCounter
+ */
+ public native long highResFrequency();
+
+ private static native void registerNatives();
+
+ static {
+ registerNatives();
+ instance = new Perf();
+ }
+}