Menu
On a multicore machine, does the JVisualVM CPU usage graph show total machine CPU capacity or something else?
As an example, on a machine with 16 cores, if I see CPU usage in JVisualVM going up to 50 percent, does that mean the equivalent of 8 cores fully in use?
830
JConsole uses only JMX, but VisualVM uses other monitoring technologies like Jvmstat, Attach API and SA in addition to JMX. It can merge data from all those monitoring technologies in one place and the user does not need to think which technology he should use in particular situation.
There are two ways to connect a remote JVM application to VisualVM: Either using jstatd or Java Management Extensions (JMX). The jstatd program is an RMI server that bundled with the JDK and monitors JVM and provides an interface to allow remote monitoring tools to attach to JVM running on the localhost.
GC (Garbage Collection) is a automatic process of clamming unused allocated memory which was previously allocated. It is an important process to make room for further memory allocation and developer need not to explicitly deallocate memory. it helps in eliminating memory leaks and other memory-related problems.
The Profiler tab of an application enables you to start and stop the profiling session of a local application. Profiling results are displayed in the Profiler tab. You can use the toolbar to refresh the profiling results, invoke garbage collection and save the profiling data.
I just tested with VisualVM 1.3.2 and the CPU display is calibrated so that 100% is 100% of all cores.
I tested by creating a simple application that entered a tight while loop upon launch. I verified using Activity Monitor that Java was using 100% of one core. In VisualVM it showed approximately 12% CPU usage.
131
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
