Note that the application must be started by the user running the host VisualVM instance, otherwise the profiling data may not be available.Īfter submitting the Profile Startup dialog, the profiler checks whether the target Java platform has already been calibrated for profiling. The profiler checks whether the application hasn't been started prior to submitting the dialog and eventually asks the user to terminate it if started too soon.
Once the target application is configured, it is important to submit the Profile Startup dialog first and after that start the application.
This will provide you with additional monitoring and troubleshooting features for the application like displaying CPU usage or taking heap dumps which are not available by default. When profiling startup of a Java 5 application, you may also want to add another parameter before the -agentpath parameter to enable the JMX agent in profiled application. The command to start the profiled application typically looks like this:Ĭ:\jdk1.7.0_64b\bin\java.exe -agentpath:C:/VisualVM/profiler/lib/deployed/jdk16/windows-amd64/profilerinterface.dll=C:\VisualVM\profiler\lib,5140 -jar MyApp.jar Note that the parameter changes by selecting different configurations in the first step. Add the provided parameter to its JVM arguments. Make sure the application is configured to run using the defined Java platform and architecture.
Visualvm vs jprofiler how to#
The third step instructs how to setup the target application and start the profiling session. To see the call trees for CPU data or stack traces for memory allocations, take a snapshot of the profiling results! Once the profiling session starts and the profiled application opens in VisualVM, you can see the live profiling data, which is just a subset of the information provided by the profiler.
Visualvm vs jprofiler code#
If you want to find out from where in the code the objects are being allocated, select the Record allocations stack traces option. Tracking each 10th object (the default) is typically enough to see the allocation trends and/or monitor the Generations count. The profiling overhead is always significant when profiling memory, but can be reduced a bit by not tracking each object's allocation.
The Profile object allocations mode can be used to see live instances and their trends. The Profile object allocations and GC mode is useful for uncovering slow memory leaks as it provides the Generations count (see the What Do The Surviving Generations Metrics Mean? article for details). When custom starting points are defined, the Profile new Runnables option should typically be unchecked.įor Memory profiling, you can continue with the defaults. The more concrete starting point and restrictive Profile only/Do not profile filter you define, the lower is the profiling overhead. To get a reasonable profiling data, you should define custom starting point like org.mypackage.** or a more specific .* or 圜lass. Note that the profiling overhead will be significant in this case. At least you should clear the text field, which will setup the profiler to start profiling from the application's main method and will also profile each new Thread and/or Runnable. See the tooltip for a hint on the required format. See the Profiling With VisualVM, Part 2 article for detailed information on the profiling settings.įor CPU profiling, you have to define the profiling starting point(s). Choose whether you want to profile performance or memory of the application and define the desired settings. The second step defines profiling settings used for the session.
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