Thank you Markus.
That was helpful.
Kind regards,
Djordje Spasic
From: Markus Schaber <[email protected]>
To: Djordje Spasic <[email protected]>
Cc: Discussion of IronPython <[email protected]>
Sent: Tuesday, December 22, 2015 11:04 AM
Subject: RE: [Ironpython-users] Delete a large object in ironpython, and
releasing the memory?
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div.yiv9528227099WordSection1 {}#yiv9528227099 Hi, IronPython runs on .NET
which has a very different garbage collector than the one used in cPython.
cPython uses reference counting, and a synchronous collector which collects
cyclic garbage. Thus, objects which are not parts of cycles are guaranteed to
be collected in the very moment when the last reference to them is removed, and
the “del” statement is one way this could happen. (Just setting the variable
reference None or some other object, or the variable dropping out of scope are
some other possibilities.) However, collection of cyclic garbage happens
somewhere later, depending on the thresholds of newly allocated objects.
(Seehttps://docs.python.org/2/library/gc.html). IronPython uses the .NET
garbage collector which does not employ reference counting (at least not in
Microsoft .NET, Mono and Rotor). Garbage collection always happens at a
non-deterministic time – usually triggered by the “memory pressure” of the
current process, which is mostly related to the amount of allocated memory over
time. In both cases, gc.collect() forces a complete garbage collection to
occur now. (Actually, gc.collect() on IronPython mainly calls to
System.GC.Collect() for this purpose, apart from performing some IronPython
specific cleanups.) Usually, there is no need to actively call the garbage
collector – however, if you really have several hundred MBs of Memory which you
want to release back to the OS immediately, I think it is justified to call the
garbage collector. Especially if your process will not allocate any memory
soon, the GC might not kick in for a long time if you don’t call it explicitly.
However, I want to emphasize that this is a special case, and generally,
“normal” applications do not need to call the garbage collector explicitly, and
should not (as frequent calls to the GC will impact performance negatively).
Best regards
Markus Schaber
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Ironpython-users
[mailto:[email protected]]On Behalf Of
Djordje Spasic via Ironpython-users
Sent: Monday, December 21, 2015 5:19 PM
To: [email protected]
Subject: [Ironpython-users] Delete a large object in ironpython, and releasing
the memory? I am a creating a huge mesh object (some 900 megabytes in size)
in Rhino3d application by using its ironpython 2.7 interpreter. Once I am done
with analysing this mesh, I would like to somehow delete it from the memory.
I did a bit of search on stackoverflow.com, and I found out that "del"
statement will only delete the reference to mentioned mesh. Not the mesh object
itself.
And that after some time, the mesh object will eventually get garbage
collected. At least this is what some users on stackoverflow say about the
regular cpython.
Is "gc.collect()" the only way by which I could instantly release the memory,
and there for somehow remove the mentioned large mesh from the memory?
I've also found replies on stackoverflow.com which state that "gc.collect()"
should be avoided (at least when it comes to regular python, not specifically
ironpython).
I've also find comments on stackoverflow which claim that in IronPython it is
not even guaranteed the memory will be released if nothing else is holding a
reference.
Any comments on all these issues?
Is it even possible to instantly free the memory from the deleted large object
in ironpython (2.7)?
Thank you for the reply.
Kind regards,
Djordje Spasic
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