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I have posted on this before, but thought I had tracked it down to the NW extension, however, memory leakage still occurs in the latest version. I found this thread, which discusses a similar issues, but attributes it to Behavior Space:

http://netlogo-users.18673.x6.nabble.com/Behaviorspace-Memory-Leak-td5003468.html

I have found the same symptoms. My model starts out at around 650mb, but over each run the private working set memory rises, to the point where it hits the 1024 limit. I have sufficient memory to raise this, but in reality it will only delay the onset. I am using the table output, as based on previous discussions this helps, and it does, but it only slows the rate of increase. However, eventually the memory usage rises to a point where the PC starts to struggle. I am clearing all data between runs so there should be no hangover. I noticed in the highlighted thread that they were going to run headless. I will try this, but I wondered if anyone else had noticed the issue? My other option is to break the BehSpc simulation into a few batches so the issues never arises, bit i would be nice to let the model run and walk away as it takes around 2 hours to go through.

Simon Bush
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  • Does the problem happen when not using the NW extension? – Bryan Head Jul 30 '14 at 21:55
  • previously: http://stackoverflow.com/q/24397338/86485 – Seth Tisue Jul 31 '14 at 07:21
  • also previously: http://stackoverflow.com/q/24521206/86485 – Seth Tisue Jul 31 '14 at 07:33
  • Which release candidate of 5.1 have you tried? It sounds like it could be [this issue](https://github.com/NetLogo/NW-Extension/pull/124), which has been fixed in [the final release of 5.1](http://ccl.northwestern.edu/netlogo/5.1.0/) – Nicolas Payette Jul 31 '14 at 14:18
  • I have now started using the new bundled NW extension with 5.1. Having carried out a few time tests there is no slowing down. The memory usage does rise quite quickly , but then levels out at the xmx limit. Also speeded the model up by simply loading the graphml instead of creating new all the time. – Simon Bush Aug 03 '14 at 23:21

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Some possible next steps:

1) Isolate the exact conditions under which the problem does or not occur. Can you make it happen without involving the nw extension, or not? Does it still happen if you remove some of the code from your model? What if you keep removing code — when does the problem go away? What is the smallest code that still causes the problem? Almost any bug can be demonstrated with only a small amount of code — and finding that smallest demonstration is exactly what is needed in order to track down the cause and fix it.

2) Use standard memory profiling tools for the JVM to see what kind of objects are using the memory. This might provide some clues to possible causes.

In general, we are not receiving other bug reports from users along these lines. It's routine, and has been for many years now, for people to use BehaviorSpace (both headless and not) and do experiments that last for hours or even for days. So whatever it is you're experiencing almost certainly has a more specific cause -- mostly likely, in the nw extension -- that could be isolated.

Seth Tisue
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