This chapter describes the new features and enhancements in Oracle JRockit Mission Control.
This chapter includes the following topics:
Oracle JRockit Mission Control 4.1 release includes the following new features and enhancements:
You can use Oracle JRockit Mission Control 4.1 with Java SE 7. Oracle JRockit Mission Control can also start the local management on Hotspot JDK 1.6 and later. However, you will still need to connect to a JRockit JVM to be able to use most of the JRockit Mission Control tools.
Note that some of the features of the Management Console are not available when JRockit Mission Control 4.1.x client is used to monitor Java SE 7 JVM.
Oracle JRockit Mission Control client 4.1 works on new platforms. Oracle JRockit Mission Control is available as technology previews on Mac OS X, Solaris x86, and Solaris SPARC. The technology previews are available as Eclipse plug-ins. For more information about how to install the plug-ins, vist the Eclipse Update Site at: http://download.oracle.com/technology/products/missioncontrol/updatesites/base/4.1.0/eclipse/.
Oracle JRockit Mission Control 4.1 client is built to run on Eclipse 3.7 and later.
Starting with Oracle JRockit Mission Control 4.1, the installers for Oracle JRockit JDK with Oracle JRockit Mission Control on Windows associate JRockit Flight Recorder (.jfr) files with the highest version of JRockit Mission Control client installed in your machine. The files with the .jfr extension are opened in the JRockit Mission Control client by default when you run the following command:
product_install_dir\bin\jrmc.exe -open recording.jfr
DTrace Plug-in for JRockit Mission Control is now available at the Update site.
To install the plug-in for the stand-alone version of JRockit Mission Control, select Install plug-ins... from the Help menu of JRockit Mission Control client. To install the DTrace plug-in for Eclipse, first install the Eclipse plug-in version of JRockit Mission Control and then install the DTrace plug-in from the JRockit Mission Control Experimental Update Site.
JRockit Mission Control provides a domain specific language (DSL) for defining DTrace events. This DSL extends the DScript syntax to make the data self describing. The default .de script provides probes for recording both HotSpot as well as the data from the operating system. This makes it easier to bring the the data into the JRockit Mission Control event model. If you run JRockit Mission Control on Eclipse, the DSL provides an editor with features such as syntax highlighting.
The DTrace Recording wizard allows you to configure the parameters declared in the .de file as well as to enable and disable probe sets.
The DTrace Analysis GUI provided with the DTrace plug-in uses the JRockit Flight Recorder components and GUI editor.
The Management Console of the JRockit Mission Control 4.1 client includes the following new features and enhancements:
Improved file resource operations in the Eclipse environment.
Improved zooming in capability for charts.
Default trigger rules are available for deadlocks.
Coherence plug-in is available at the Update site.
Introduced two new tabs, Server Information and Native Memory.
Enhancements in Overview and Thread tabs to support HotSpot JVM.
JRockit Flight Recorder includes the following new features and enhancements:
The Thread graph renders thread transition information.
Improved selection and zooming in the Thread graph.
Long thread names in the Thread graph will be truncated and only the important information will be displayed.
A new operative set action adds all events occurring during the same time and in the same thread as a selection of events to the operative set.
The performance of the parser as well as the memory footprint has been optimized.
The built-in GUI editor of JRockit Mission Control has been improved.
JRockit Memory Leak Detector includes the following new features and enhancements:
Introduced context menu options for selecting a random instance and class loader of the type.
An extension point is now available for better instance visualization.
The Trend Analysis table now includes columns that show the instance count and memory growth. You can reset these columns.
Introduces an option to increase the instance limit directly from the instance view.
Introduces a toggle switch in the toolbar to switch between the graph and tree representations.
The JRockit Mission Control 4.0 release includes the following new features and enhancements:
Restart Prompt Added When High Contrast Mode is Enabled or Disabled
Welcome Page Added to RCP Version of JRockit Mission Control
The Oracle JRockit Mission Control update site now requires Eclipse 3.5.
The JRockit Flight Recorder is a performance monitoring and profiling tool that makes diagnostics information always available, even in the wake of catastrophic failure, such as a system crash. At its most basic, JFR is a rotating buffer of diagnostics and profiling data that is always available, on demand. You might consider it a sort of "time machine" that enables you to go back in time to gather diagnostics data leading up to an event. The data stored in the rotating buffer includes JVM and application events.
In JRockit Mission Control 4.0 Client, the Flight Recorder allows users who are running a Flight Recorder-compliant version of the Oracle JRockit JVM (that is, version R28.0 or later) to view the JVM's recordings, current recording settings, and runtime parameters on a series of tabs that aggregate performance data into logical, task-based groups. The data on these tabs is presented by way of an assortment of dials, chart, and tables. At the top of each tab is a sliding window, called the Range Navigator, with which you can expand or narrow the range of reporting; for example, if you see a group of events clustered around a specific time period, you can adjust the Range Navigator to include just those events, with the resulting data for just those events appearing on the tab components.
Making flight recordings is simplified by using Flight Recording Wizard, which allows you to create recordings by using templates that define the sort of event information you want reported. When you use the Wizard, you select the template that you want to use, the duration of the recording, and the file name under which you wan the recording stored. You can also use the Wizard for such advanced tasks as modifying an existing template, saving a modified template for future use, or importing and using a template from another server
The Flight Recorder supplants the JRockit Runtime Analyzer available in earlier versions of JRockit Mission Control.
The JRockit Memory Leak Detector has been updates, as described in these sections:
Versions of the Memory Leak Detector in JRockit Mission Control 3.1 and earlier were basically Swing applications. This was required to enable support for J2SE 1.4 on all platforms. JRockit Mission Control 4.0 Client is a component of Oracle JRockit JDK R28.0, from which support for J2SE 1.4 has been dropped, and can now use SWT/JFace components for its graphical user interface. The ultimate result of this change is the Memory Leak Detector GUI has the same look and feel as the other JRockit Mission Control plug-ins.
For any instance, you can now see multiple levels of back references at once by automatically expanding the shortest path to a garbage collection root. In previous versions of JRockit Mission Control, a user would need to follow references back to the root when, for instance, using large frameworks. When the depth was more than a trivial amount of references deep and/or the branching factor was large (that is, with many instance variables or references), this was a very inefficient and often confusing process. Now, you can expand to the garbage collection root simply by selecting Expand to Root from a context menu on a highlighted node.
Earlier versions of the Memory Leak Detector made it difficult to find all instances of a specific type. Now, wherever there is a type, the context menu enables you to List All Instances. The instances will appear on an Instances table in the left-hand panel of the Memory Leak Detector GUI.
You can now investigate memory leaks based upon their class loader. In previous versions, no matter how many actual types you had with a certain class name (each loaded by a different class loader) they were all lumped together and displayed as a single type. Now, you may, per view, switch between this mode and to actually show all the loaded classes, including the class loader that loaded each of them.
JRockit Mission Control Client now displays a message dialog box and prompts you to restart Mission Control when high contrast mode is turned on or off in the operating system.
The RCP/standalone version of JRockit Mission Control 4.0.0 features a welcome page that provides a brief introduction to the product.
The auto-scale feature in this version of JRockit Mission Control Client has been improved:
Auto-scale in graphs has been improved and is now based only on values visible in the graph.
You can now use auto-scale while always showing the zero level in graphs in the Management Console.
You can now sort the columns in a table from the context menu (as well as by clicking on the column header as before).
Data series with only a single value are now easier to see in graphs. The single value is marked with an X in line graphs and you can optionally extrapolate line graphs and filled graphs to mark the "missing" data on both sides of a data series.
The new accessibility option Show labels on buttons enables text labels on buttons and icons that otherwise only have a description in a tool tip.