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How to estimate the APM Agent footprint

Question asked by LutzM Champion on Jun 27, 2018
Latest reply on Jun 28, 2018 by LutzM

Hello all folks,

a short time ago we moved our application environment from Websphere to Liberty Profile. Unfortunately the CPU usage increase more than expacted. Any idea how to calculate the Java Agent footprint in a JVM (we use IBM Java 8, AIX 7.1, APM 10.5.1, the "Default Agent" package) in a easy and usefull way.

Thanks for any suggestion,

Lutz

 

p.s.

We use the javacore files (taken two times a day) to get a CPU usage overview (see "3XMCPUTIME") and assign all "Agent*" and "*Hub*" threads to the Java Agent footprint.

 

For example,

3XMTHREADINFO      "UnknownHub Hub Receive 189" J9VMThread:0x0000000034F4A400, j9thread_t:0x0000010043B443F0, java/lang/Thread:0x00000000F4BD6D20, state:R, prio=5
3XMJAVALTHREAD            (java/lang/Thread getId:0x5DE, isDaemon:true)
3XMTHREADINFO1            (native thread ID:0x9504B9, native priority:0x5, native policy:UNKNOWN, vmstate:R, vm thread flags:0x00000020)
3XMCPUTIME               CPU usage total: 0.191125000 secs, user: 0.076544000 secs, system: 0.114581000 secs, current category="Application"
3XMHEAPALLOC             Heap bytes allocated since last GC cycle=0 (0x0)
3XMTHREADINFO3           Java callstack:

3XMTHREADINFO      "Agent Heartbeat" J9VMThread:0x000000003064E100, j9thread_t:0x00000100225AE350, java/lang/Thread:0x00000000E01AF0B8, state:R, prio=5
3XMJAVALTHREAD            (java/lang/Thread getId:0x17, isDaemon:true)
3XMTHREADINFO1            (native thread ID:0x1A80457, native priority:0x5, native policy:UNKNOWN, vmstate:CW, vm thread flags:0x80000001)
3XMCPUTIME               CPU usage total: 14.973503000 secs, user: 14.859944000 secs, system: 0.113559000 secs, current category="Application"
3XMHEAPALLOC             Heap bytes allocated since last GC cycle=0 (0x0)
3XMTHREADINFO3           Java callstack:

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