[Ironpython-users] Analyzing the Memory Leak

[Markus Schaber]

Hi,

I'm currently trying to analyze the memory leak http://ironpython.codeplex.com/workitem/31764

One thing I found out so far is that sys.settrace (which is called by Python.SetTrace internally) seems to call pyContext.PushTracebackHandler without ever pulling that handler. 

I did insert some debug output, and it really seems that we're leaking one PythonTracebackListener instance (which internally references the PythonContext) on the thread static _tracebackListeners stack, which keeps all PythonContext instances which ever set a trace alive forever.

However, it seems this is not the only place where the PythonContexts are kept alive, because I tried to replace the Reference within the PythonTracebackListener with a Weak Reference, and the memory still leaked.

But when just not enabling ScriptTracing, the memory leak is reduced drastically, so I'm sure I'm on the right way to uncover at least one of the culprits.


PS:
One annoying thing is that "ClrProfiler" throws Exceptions when trying to get the memory dumps:

System.NullReferenceException: Der Objektverweis wurde nicht auf eine Objektinstanz festgelegt.
   bei CLRProfiler.LiveObjectTable.InsertObject(UInt64 id, Int32 typeSizeStacktraceIndex, Int32 allocTickIndex, Int32 nowTickIndex, Boolean newAlloc, SampleObjectTable sampleObjectTable) in C:\CLRProfilerHelper\CLRProfiler\Sources\CLRProfiler\ReadNewLog.cs:Zeile 1030.
   bei CLRProfiler.ReadNewLog.ReadFile(Int64 startFileOffset, Int64 endFileOffset, ReadLogResult readLogResult, Int32 requestedIndex) in C:\CLRProfilerHelper\CLRProfiler\Sources\CLRProfiler\ReadNewLog.cs:Zeile 2440.
   bei CLRProfiler.MainForm.showHeapButton_Click(Object sender, EventArgs e) in C:\CLRProfilerHelper\CLRProfiler\Sources\CLRProfiler\MainForm.cs:Zeile 2874.

Do you know of any other good and free (as in beer) tool for memory debugging?



Best regards

Markus Schaber
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