JVM

This function monitors JVMInfo, JVMMonitor, GC, thread, and JavaMethod.

Going to the JVM Page

Log in to the management console.
Click on the left and choose Application > Application Performance Management.
In the navigation pane, choose Application Monitoring > Metrics.
In the tree on the left, click next to the target environment.
Click the JVM tab. By default, the JVMMonitor information of all instances is displayed.

Figure 1 Going to the JVM page
On the displayed JVM tab page, select a target instance and metric to view the monitoring data in different metric sets.

Figure 2 Selecting a target instance and metric
Select a time dimension. Default: Last 20 minutes.

Options: Last 20 minutes, Last hour, Last 3 hours, Last 6 hours, Last day, Today, Yesterday, Last 7 days, Last 30 days, or Custom.

Figure 3 Selecting a time dimension
Click in the upper right corner of the list and select the metric data you want to view.

Viewing JVM Information

On the JVM tab page, view the JVM metrics of the corresponding instance. For details about the metrics, see Table 1.

Figure 4 Viewing JVM information
Click to enlarge

**Table 1** JVMInfo metrics
Metric Set	Metric	Description
JVMInfo	JavaAgent Version	Java Agent version
	Started	JVM startup time
	Startup Parameter	JVM startup parameter
	Java Class Library Path	Java class library path
	Java Version	Java version
	Java Specification Version	Java specification version
	OS	OS name
	OS Version	OS version
	arch	CPU architecture
	Processors	Number of processors
	SDK Version	SDK version

Viewing JVM Monitoring Data

APM monitors JVM metrics. For details about the metrics, see Table 2. JVM monitoring metrics are displayed in graphs, so that you can view and analyze JVM monitoring data more easily.

Figure 5 Viewing JVM monitoring data
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**Table 2** JVM monitoring metrics
Metric Set	Metric	Description
Thread	Current Threads	Number of current threads
	Deadlock Threads	Number of deadlock threads
	Daemon Threads	Number of daemon threads
	Started Threads	Number of started threads
	Peak Threads	Peak number of threads
Thread Status	Waiting Threads	Number of waiting threads
	Initial Threads	Number of threads in the initial state
	Running Threads	Number of running threads
	Blocked Threads	Number of blocked threads
	Terminated Threads	Number of terminated threads
	Timed Waiting Threads	Number of threads that timed out
Memory	Used Non-Heap Memory	Size of the used non-heap memory
	Used Heap Memory	Size of the used heap memory
	Used Direct Memory	Size of the used direct memory
Class loading	Current Classes	Number of current classes
	Total Loaded Classes	Total number of loaded classes
	Unloaded Classes	Number of unloaded classes
Memory pool	Available Memory	Size of available memory
	Initialized Memory	Size of the initialized memory
	Max. Memory	Size of the maximum memory
	Name	Memory pool name
	Used Memory	Size of the used memory
CPU	CPU Usage	CPU usage of the Java process

Viewing GC Information

APM monitors GC metrics. For details about the metrics, see Table 2.

Figure 6 Viewing GC information
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**Table 3** GC metrics
Metric Set	Metric	Description
GC statistics	Full GC (times)	Number of full GC times in a collection period
	Full GC Duration (ms)	Full GC duration in a collection period
	Young GC (times)	Number of young GC times in a collection period
	Young GC Duration (ms)	Young GC duration in a collection period
GC Details	GC Type	GC type, which can be major or minor
	GC Cause	GC cause
	Count	Number of times that GC has occurred
	Total GC Duration (ms)	GC duration
	Max GC Duration (ms)	Time consumed by the slowest GC
	GC Recycler	GC recycler name
	Slowest GC Details	Details about the slowest GC

Click the digits in blue (such as those in the Count, Total GC Duration (ms), or Max GC Duration (ms) column) to view the corresponding GC trend graph in a certain period (default: 20 minutes).
On the GC details area, you can view the GC type, GC cause, count, total GC duration (ms), maximum GC duration (ms), GC recycler, and slowest GC details (details and history).

Viewing Threads

You can view the thread details of the corresponding instance on APM. For details, see Table 4.

Figure 7 Viewing threads
Click to enlarge

**Table 4** Thread metrics
Metric Set	Metric	Description
Thread details	Thread Name	Thread name
	Threads	Number of threads
	CPU Time (ms)	Thread CPU time
	Memory (MB)	Memory (MB)
	Thread Stack	Thread stack

Click a number in the Threads column to view the trend of the thread in a specified period.
Click Details in the Thread Stack column to view the thread details.
Click History in the Thread Stack column to view the historical thread stack list.

Viewing Java Methods

By default, APM does not monitor Java methods. To monitor them, configure the JavaMethod monitoring item first.
After the configuration is complete, the system monitors the methods and classes of JavaMethod.
On the JVM page, select a target instance and JavaMethod to view details. For details, see Table 5.

**Table 5** JavaMethod metrics
Metric Set	Metric	Description
JavaMethod	Class	Class
	Method	Method
	Calls	Number of times that the method is called
	Avg RT (ms)	Average response time
	Errors	Number of times that the method fails to be called
	Max Concurrency	Maximum concurrency of the method
	Max RT (ms)	Maximum response time of the method
	0–10 ms	Number of requests with 0–10 ms response time
	10–100 ms	Number of requests with 10–100 ms response time
	100–500 ms	Number of requests with 100–500 ms response time
	500–1000 ms	Number of requests with 500–1000 ms response time
	1–10s	Number of requests with 1–10s response time
	> 10s	Number of requests with response time longer than 10s