How is the metric "GCMonitor : Percentage of Java Heap Used" calculated.

Document ID : KB000014181
Last Modified Date : 14/02/2018
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Question:

How is the metric "GCMonitor : Percentage of Java Heap Used" calculated?

Environment:
Apm 9.6 to 10.x
Answer:

GC Monitor:Percentage of Java Heap Used" metric is calculated with this formula:

(GC Heap:Bytes In Use ÷ GC Heap:Bytes Total) * 100

Solution:

  1. "GC Monitor:Percentage of Java Heap Used" metric is calculated with this formula: 

    (GC Heap:Bytes In Use ÷ GC Heap:Bytes Total) * 100 

  2. The above metric when calculated should be approximately equal to the average obtained by doing the below calculation for each of the memory pools(for example: old space, nursery, class memory in case of Jrockit JVM). 

    (Amount of Space used ÷ Current capacity) * 100
Additional Information:

For more info on GC metrics,

https://docops.ca.com/ca-apm/10/en/using/apm-metrics/resource-metrics/memory-related-metrics