VisualVM and Self Time

java performance profiling cpu visualvm
AndyF picture AndyF · Jan 31, 2013 · Viewed 24.5k times · Source

I've been searching all over for a consistent and clear explanation of what 'self time' actually refers to in the VisualVM context and how does it differ to 'self time (cpu)'. Also does 'self time [%]' refer to self time or self time cpu.

There doesn't appear to be much documentation on this or at least I haven't found it. So any thoughts/input will be appreciated.

Answer

Tomas Hurka picture Tomas Hurka · Feb 1, 2013
  • Self Time is a wall-clock time spent in the method itself (includes time waiting/sleeping).
  • Self Time (CPU) is a time processor time, so it does NOT include time spent waiting, sleeping, etc.

  • Both columns do NOT include time spent in methods invoked from that method.
  • Both Self Time and Self Time (CPU) in the sampler are approximation of actual data.
  • Self Time [%] refers to one of the two selected Self Time [(CPU)] columns.

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