io.prometheus.client.utility.jvmstat

Class JvmstatMonitor

java.lang.Object

io.prometheus.client.utility.jvmstat.JvmstatMonitor

All Implemented Interfaces:

Prometheus.ExpositionHook, Runnable

public class JvmstatMonitor
extends Object
implements Prometheus.ExpositionHook

JvmstatMonitor provides HotSpot-specific JVM metrics through the MonitoredVm facilities.

These low-level metrics are defined in the C++ bowels of the HotSpot VM through internal measurement types. The VM exposes these through the HSPerfData interface for customers. Typically one accesses this data via a MMAPed direct buffer—namely Java native I/O (nio).

Important Notes

Due to inconsistencies of virtual machine packages and vendoring, the following remarks should be carefully observed:

• Users may need to explicitly add ${JAVA_HOME}/lib/tools.jar to the CLASSPATH when using this helper. This is because the sun.jvmstat.monitor package hierarchy is not a part of the standard Java library. These packages are, however, typically included in Sun-, Oracle-, and OpenJDK-provided virtual machines, which is to say they are ubiquitous in most deployment environments.
• Users may need to explicitly set -XX:+UsePerfData in the VM's flags to enable low-level telemetric export.

The metrics that this class exposes are dependent upon the release of HotSpot, including even minor releases. Depending on that, it may be possible to use adapt this utility to be more flexible by incorporating support for common metric aliases, as defined in sun/jvmstat/perfdata/resources/aliasmap.

Author:

Matt T. Proud (matt.proud@gmail.com)

See Also:

Prometheus.addPreexpositionHook(io.prometheus.client.Prometheus.ExpositionHook), MonitoredVm

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	JvmstatMonitor.AttachmentError A JvmstatMonitor.AttachmentError indicates that it was impossible to attach to the requested virtual machine.
static class	JvmstatMonitor.ClassLoaderInstrumentation Provide visibility about the internals of the JVM's class loader.
static class	JvmstatMonitor.GarbageCollectionInstrumentation Provide visibility about the internals of the JVM's garbage collector.
static class	JvmstatMonitor.ManagedMemoryInstrumentation Provide visibility about the internals of the JVM memory regions.
static class	JvmstatMonitor.NativeCodeCompilerInstrumentation Provide visibility about the internals of the JVM's just-in-time (JIT) compiler.

Constructor Summary

Constructors

Constructor and Description
JvmstatMonitor() Create a JvmstatMonitor for the local virtual machine associated with this specific Java server.
JvmstatMonitor(sun.jvmstat.monitor.MonitoredVm b) Create a JvmstatMonitor monitoring bridge with a supplied MonitoredVm.

Method Summary

Methods

Modifier and Type	Method and Description
void	run()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

JvmstatMonitor

public JvmstatMonitor()
               throws JvmstatMonitor.AttachmentError

Create a JvmstatMonitor for the local virtual machine associated with this specific Java server.

Throws:

{@link - AttachmentError} if the VM cannot be attached to.

JvmstatMonitor.AttachmentError

JvmstatMonitor

public JvmstatMonitor(sun.jvmstat.monitor.MonitoredVm b)

Create a JvmstatMonitor monitoring bridge with a supplied MonitoredVm.

This is only useful for reusing an existing MonitoredVm or for testing purposes. Users are encouraged to use the JvmstatMonitor() default constructor.

Parameters:

b -

Method Detail

run

public void run()

Specified by:

run in interface Runnable