true Thread ID Hidden 0 Thread ID Thread ID Hidden GROUP Wait Time (ns) BUCKET Count true true BUCKET_FREQUENCY true <html>Example distribution of monitor wait times from<br> <b>DTrace and Java: Exposing Performance Problems That Once Were Hidden</b><br> by <i>Jarod Jensen</i><br> <br> (Quoted from the article):<br> 'Perhaps you are seeing monitor contention that is affecting scalability in your application. One question you might have is: "How long do I wait from the time I attempt to acquire the contended monitor until I actually enter the monitor?" Now you can create a little DTrace script to answer that question.'<br> <br> See http://www.devx.com/Java/Article/33943 <br><br> See also <b>DTrace Probes in HotSpot VM</b><br> http://java.sun.com/javase/6/docs/technotes/guides/vm/dtrace.html</html> zdefs set hotspot$target:::monitor-contended-enter { self->ts = timestamp; } hotspot$target:::monitor-contended-entered / self->ts / { @[tid] = quantize(timestamp - self->ts); self->ts = 0; } true 400 541 Monitor Wait Times 2