Using the VM Operations Page

The VM Operations page contains time and duration statistics for VM operations.

This page presents VM operations data in tables, graphs, and subtabs.

Using the VM Operations Page: Selections and Aspects

Use the drop-down menus at the top of the page to choose a selection and aspect if desired. Data from other pages can be saved to the selection drop-down menu by dragging an area of a chart (or selecting data from a table) and choosing Store Selection or Store Selection and Set As Focused Selection from the context menu.

The following controls provide additional behavior:

Show concurrent: Show all events concurrent to the selected aspect.
Contained: Only show events that are fully contained in the time range from the active selection aspect
Same threads: Only show events in threads related to the active selection aspect.

Using the VM Operations Page: Tables and Graphs

Table columns are labeled as follows:

VM Operation: The kind of VM operation.
Longest Duration: The longest duration for this VM operation.
Total Duration: The total duration time for this VM operation.
StdDev(P): The duration standard deviation.
Count: The number of times this VM operation was executed.

This page also contains three additional subtabs: Timeline, Durations, or Event Log.

Timeline

The graph on this subtab plots VM operations along a timeline.

Durations

The graph on this subtab plots VM operations by duration.

Event Log

This table on this subtab provides the following information:

Start Time: The time that the VM operation began at.
VM Operation: The kind of VM operation.
Blocking: Whether the thread calling the VM operation was blocked or not.
Safepoint: Whether the VM operation occurred at a safepoint or not.
Duration: The duration of the VM operation
Caller: The thread requesting the operation.

Using the VM Operations Page: Configuring Rules

You can set configuration attributes for the rules associated with this page by clicking the Edit Configuration icon.

The following options are available:

Biased Locking Revocation

Biased locking warning limit time: The total time spent blocked on revoking biased locks needed to trigger a warning.

VMOperation Peak Duration

Blocking vm operation duration warning limit: The minimum duration for a blocking VM operation needed to trigger a warning.