Administration Console Online Help

Previous Next Open TOC in new window
Content starts here

Servers: Monitoring: Performance

Configuration Options     Related Tasks     Related Topics

This page lets you monitor performance information about this server. You can also use this page to force garbage collection or a thread dump.

Configuration Options

Name Description
Execute Thread Current Idle Count

The number of idle threads assigned to the queue.

MBean Attribute:
ExecuteQueueRuntimeMBean.ExecuteThreadCurrentIdleCount

Oldest Pending Request

The time since the longest waiting request was placed in the queue.

MBean Attribute:
ExecuteQueueRuntimeMBean.PendingRequestOldestTime

Serviced Request Total Count

The number of requests that have been processed by the queue.

MBean Attribute:
ExecuteQueueRuntimeMBean.ServicedRequestTotalCount

Queue Length

The number of waiting requests in the queue.

MBean Attribute:
ExecuteQueueRuntimeMBean.PendingRequestCurrentCount

Heap Free Current

The current amount of memory (in bytes) that is available in the JVM heap.

MBean Attribute:
JVMRuntimeMBean.HeapFreeCurrent

Heap Size Current

The current size (in bytes) of the JVM heap.

MBean Attribute:
JVMRuntimeMBean.HeapSizeCurrent

Heap Size Max

The maximum free memory configured for this JVM.

MBean Attribute:
JVMRuntimeMBean.HeapSizeMax

Heap Free Percent

Percentage of the maximum memory that is free.

MBean Attribute:
JVMRuntimeMBean.HeapFreePercent

Total Physical Memory

The amount (in bytes) of physical memory on the host computer.

The value does not include memory that an operating system makes available through swap space on a disk or other types of virtual memory.

MBean Attribute:
JRockitRuntimeMBean.TotalPhysicalMemory

Free Physical Memory

The amount (in bytes) of physical memory that is currently free on the host computer.

MBean Attribute:
JRockitRuntimeMBean.FreePhysicalMemory

Used Physical Memory

The amount (in bytes) of physical memory that is currently being used on the host computer.

The value describes the memory that is being used by all processes on the computer, not just by the Virtual Machine.

MBean Attribute:
JRockitRuntimeMBean.UsedPhysicalMemory

Total Heap

The amount (in bytes) of memory currently allocated to the Virtual Machine's Java heap.

This value, which is also known as the "heap size," may grow up to the specified maximum heap size.

MBean Attribute:
JRockitRuntimeMBean.TotalHeap

Free Heap

The amount (in bytes) of Java heap memory that is currently free in the Virtual Machine.

MBean Attribute:
JRockitRuntimeMBean.FreeHeap

Used Heap

The amount (in bytes) of Java heap memory that is currently being used by the Virtual Machine.

MBean Attribute:
JRockitRuntimeMBean.UsedHeap

GC Algorithm

The type of garbage collector (GC) that the Virtual Machine is using.

JRockit provides the following types of GCs:

  • Generational Copying, which is suitable for testing applications on a desktop machine with a small (less then 128 MB) heap.

  • Single Spaced Concurrent, which reduces or eliminates pauses in the VM that are due to garbage collection. Because it trades memory throughput for reduced pause time, you generally need a larger heap size than with other GC types. If your ordinary Java threads create more garbage than this GC can collect, the VM will pause while the Java threads wait for the garbage collection to finish.

  • Generational Concurrent, which creates a "nursery" space within the heap. New objects are created within the nursery. When the nursery is full, JRockit "stops-the-world," removes the dead objects from the nursery, and moves live objects to a different space within the heap. Another thread runs in the background to remove dead objects from the non-nursery space. This GC type has a higher memory throughput than a single spaced concurrent GC.

  • Parallel, which allocates all objects to a single spaced heap. When the heap is full, all Java threads are stopped and every CPU is used to perform a complete garbage collection of the entire heap. This behavior causes longer pause times than for the concurrent collectors but maximizes memory throughput.

MBean Attribute:
JRockitRuntimeMBean.GcAlgorithm

Total GC Count

The number of garbage collection runs that have occurred since the Virtual Machine was started.

MBean Attribute:
JRockitRuntimeMBean.TotalGarbageCollectionCount

Last GC Start

The time at which the last garbage collection run started.

MBean Attribute:
JRockitRuntimeMBean.LastGCStart

Last GC End

The time at which the last garbage collection run ended.

MBean Attribute:
JRockitRuntimeMBean.LastGCEnd

Total GC Time

The number of milliseconds that the Virtual Machine has spent on all garbage collection runs since the VM was started.

MBean Attribute:
JRockitRuntimeMBean.TotalGarbageCollectionTime

Handles Compaction

Indicates whether the VM's garbage collector compacts the Java heap.

Usually the heap is scattered throughout available memory. A garbage collector that compacts the heap defragments the memory space in addition to deleting unused objects.

MBean Attribute:
JRockitRuntimeMBean.GCHandlesCompaction

Concurrent

Indicates whether the VM's garbage collector runs in a separate Java thread concurrently with other Java threads.

MBean Attribute:
JRockitRuntimeMBean.Concurrent

Generational

Indicates whether the VM's garbage collector uses a nursery space.

A nursery is the area of the Java heap that the VM allocates to most objects. Instead of garbage collecting the entire heap, generational garbage collectors focus on the nursery. Because most objects die young, most of the time it is sufficient to garbage collect only the nursery and not the entire heap.

MBean Attribute:
JRockitRuntimeMBean.Generational

Incremental

Indicates whether the VM's garbage collector collects (increments) garbage as it scans the memory space and dumps the garbage at the end of its cycle.

With a non-incremental garbage collector, garbage is dumped as soon as it is encountered.

MBean Attribute:
JRockitRuntimeMBean.Incremental

Parallel

Indicates whether the VM's garbage collector is able to run in parallel on multiple processors if multiple processors are available.

MBean Attribute:
JRockitRuntimeMBean.Parallel

Total Number Of Threads

The number of Java threads (daemon and non-daemon) that are currently running in the Virtual Machine across all processors.

MBean Attribute:
JRockitRuntimeMBean.TotalNumberOfThreads

Number Of Daemon Threads

The number of daemon Java threads currently running in the Virtual Machine across all processors.

MBean Attribute:
JRockitRuntimeMBean.NumberOfDaemonThreads

Number Of Processors

The number of processors on the Virtual Machine's host computer. If this is not a Symmetric Multi Processor (SMP) system, the value will be 1.

MBean Attribute:
JRockitRuntimeMBean.NumberOfProcessors

All Processors Average Load

A snapshot of the average load of all processors in the host computer. If the computer has only one processor, this method returns the same value as getJvmProcessorLoad(0).

The value is returned as a double, where 1.0 represents 100% load (no idle time) and 0.0 represents 0% load (pure idle time).

MBean Attribute:
JRockitRuntimeMBean.AllProcessorsAverageLoad

JVM Processor Load

A snapshot of the load that the Virtual Machine is placing on all processors in the host computer. If the host contains multiple processors, the value represents a snapshot of the average load.

The value is returned as a double, where 1.0 represents 100% load (no idle time) and 0.0 represents 0% load (pure idle time).

MBean Attribute:
JRockitRuntimeMBean.JvmProcessorLoad

Related Tasks

Related Topics


Back to Top