New Relic JVM graphs on Tomcat

Question

I am currently trying to optimise my Tomcat on a 64bit sever with 4 GB of memory. Here are my current settings and its ticking over nicely:

-Xms256m
-Xmx1024m
-XX:MaxPermSize=256m
-XX:+UseParNewGC
-XX:+UseConcMarkSweepGC
-XX:+CMSClassUnloadingEnabled

What I don't quite understand is how they relate to the New Relic charts - is the Eden space heap usage optimal - what should I be aiming on seeing in the reports?

Answer 1

The information in the charts don't exactly have a correlation to the parameters specified fro the JVM at startup because the information provided is a trend. Most, if not all, of the metrics used for the charts for the JVM are averages over the period of time specified in the picker.

To help explain, I'll share the metrics used for each chart:

Heap Memory Usage (MB)

• Memory/Heap/Committed with value_fn: average_value
• Memory/Heap/Max with value_fn: average_value
• Memory/Heap/Used with value_fn: average_value

PS Eden Space heap usage (MB)

• MemoryPool/Heap/PS Eden Space/Committed with value_fn: average_value
• MemoryPool/Heap/PS Eden Space/Max with value_fn: average_value
• MemoryPool/Heap/PS Eden Space/Used with value_fn: average_value

PS Survivor Space heap usage (MB)

• MemoryPool/Heap/PS Survivor Space/Committed with value_fn: average_value
• MemoryPool/Heap/PS Survivor Space/Max with value_fn: average_value -MemoryPool/Heap/PS Survivor Space/Used with value_fn: average_value

PS Old Gen heap usage (MB)

• MemoryPool/Heap/PS Old Gen/Committed with value_fn: average_value
• MemoryPool/Heap/PS Old Gen/Max with value_fn: average_value
• MemoryPool/Heap/PS Old Gen/Used with value_fn: average_value

Non-heap memory pool usage (MB)

• MemoryPool/Non-Heap/Code Cache/Used with value_fn: average_value
• MemoryPool/Non-Heap/PS Perm Gen/Used with value_fn: average_value

Garbage collection CPU time

• GC/PS Scavenge with value_fn: average_call_time

Class count

• JmxBuiltIn/Classes/Loaded with value_fn: average_value
• JmxBuiltIn/Classes/Unloaded with value_fn: average_value

Does this help explain the information in the charts sufficiently? Let us know if you need further assistance with this issue.