We are trying to improve our app performance and are doing a performance testing. We have a Linux VM with 4 cores and 16 GB memory. The application has more then 100 users and are complaining of slowness. Here are the performance tuning we have done so far
<heap size="8192m" max-size="8192m"/>
***<jvm-options>
<option value="-XX:+UseG1GC"/>
<option value="-XX:+UseStringDeduplication"/>
<option value="-verbose:gc"/>
<option value="-XX:+PrintGCDetails"/>
<option value="-XX:+PrintGCDateStamps"/>
<option value="-XX:+PrintGCTimeStamps"/>
<option value="-XX:+PrintGCApplicationStoppedTime"/>
<option value="-XX:+UseGCLogFileRotation"/>
<option value="-XX:NumberOfGCLogFiles=5"/>
<option value="-XX:GCLogFileSize=3M"/>
<option value="-XX:-TraceClassUnloading"/>
<option value="-XX:+HeapDumpOnOutOfMemoryError"/>***
we are seeing a 11 second garbage collection time as below
2021-09-14T18:43:27.186+1000: 14806.057: [GC pause (G1 Evacuation Pause) (young), 0.1189389 secs]
[Parallel Time: 71.8 ms, GC Workers: 4]
[GC Worker Start (ms): Min: 14806057.7, Avg: 14806057.7, Max: 14806057.7, Diff: 0.1]
[Ext Root Scanning (ms): Min: 5.4, Avg: 6.9, Max: 8.9, Diff: 3.5, Sum: 27.5]
[Update RS (ms): Min: 7.2, Avg: 9.0, Max: 9.7, Diff: 2.6, Sum: 35.8]
[Processed Buffers: Min: 30, Avg: 33.2, Max: 38, Diff: 8, Sum: 133]
[Scan RS (ms): Min: 0.3, Avg: 0.3, Max: 0.3, Diff: 0.1, Sum: 1.2]
[Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.1, Diff: 0.1, Sum: 0.1]
[Object Copy (ms): Min: 54.7, Avg: 55.3, Max: 56.0, Diff: 1.4, Sum: 221.3]
[Termination (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
[Termination Attempts: Min: 1, Avg: 1.0, Max: 1, Diff: 0, Sum: 4]
[GC Worker Other (ms): Min: 0.0, Avg: 0.1, Max: 0.1, Diff: 0.1, Sum: 0.3]
[GC Worker Total (ms): Min: 71.5, Avg: 71.6, Max: 71.6, Diff: 0.1, Sum: 286.2]
[GC Worker End (ms): Min: 14806129.2, Avg: 14806129.3, Max: 14806129.3, Diff: 0.1]
[Code Root Fixup: 0.0 ms]
[Code Root Purge: 0.0 ms]
[String Dedup Fixup: 16.8 ms, GC Workers: 4]
[Queue Fixup (ms): Min: 0.0, Avg: 0.0, Max: 0.1, Diff: 0.1, Sum: 0.1]
[Table Fixup (ms): Min: 16.0, Avg: 16.3, Max: 16.6, Diff: 0.6, Sum: 65.3]
[Clear CT: 0.5 ms]
[Other: 29.8 ms]
[Choose CSet: 0.0 ms]
[Ref Proc: 26.7 ms]
[Ref Enq: 0.9 ms]
[Redirty Cards: 0.1 ms]
[Humongous Register: 0.2 ms]
[Humongous Reclaim: 0.1 ms]
[Free CSet: 1.3 ms]
[Eden: 4072.0M(4072.0M)->0.0B(4096.0M) Survivors: 98304.0K->86016.0K Heap: 7267.0M(8192.0M)->3187.9M(8192.0M)]
[Times: user=0.38 sys=0.00, real=0.12 secs]
How do we bring it down? we are planning to add 32 GB memory to the server and have the heap size (min and max at 20 GB)
