Re: [Jython-users] Why Memory Usage Increase with a PythonInterpreter and running eval in aloop?

[Samuele P. <pe...@in...>]

Hi.

> Can anyone explain why the attached simple Java program which creates one
> PythonInterpreter and then does an eval in a continuous loop using so much
> memory on Windows 2000 and Linux?  Is it a Java problem or a Jython
> problem?  Can it be fixed?
Given your data it seems an IBM Java problem ;)
Seriously the only potential memory leak that I see is with the all
classes dynamically loaded if the VM does not discard them at some point,
which is not mandatory (see the JLS) but should be a reasonable behavior ;)
With the Sun HotSpot you have a -verbose:class option. Don't know
about the IBM VM. Here is what you see running your code:

a bunch of dynamical class loading:
[Loaded org.python.pycode._pyx4667]
[Loaded org.python.pycode._pyx4668]
[Loaded org.python.pycode._pyx4669]
[Loaded org.python.pycode._pyx4670]
[Loaded org.python.pycode._pyx4671]
[Loaded org.python.pycode._pyx4672]
[Loaded org.python.pycode._pyx4673]
[Loaded org.python.pycode._pyx4674]
[Loaded org.python.pycode._pyx4675]
[Loaded org.python.pycode._pyx4676]
[Loaded org.python.pycode._pyx4677]
[Loaded org.python.pycode._pyx4678]
[Loaded org.python.pycode._pyx4679]
...
[Unloading class org.python.pycode._pyx6636]
[Unloading class org.python.pycode._pyx6538]
[Unloading class org.python.pycode._pyx6593]
[Unloading class org.python.pycode._pyx6598]
[Unloading class org.python.pycode._pyx7066]
[Unloading class org.python.pycode._pyx7002]
[Unloading class org.python.pycode._pyx6510]
[Unloading class org.python.pycode._pyx6785]
[Unloading class org.python.pycode._pyx6621]
[Unloading class org.python.pycode._pyx6892]
[Unloading class org.python.pycode._pyx6863]
[Unloading class org.python.pycode._pyx6707]
[Unloading class org.python.pycode._pyx6633]
but also a bunch of class unloading.

If the IBM VM have similar tools, you could try to investigate the problem.
With the old sun 1.2 -verbose:class did'nt show class unloading but -verbose:gc
did.

regards.

> On  a Windows 2000 system with 128M memory using IBM Java 1.3.0 (20010609)
> with the JIT on, java.exe's memory usage for this program steadily
> increases and performance decreases.  Eventually I get an OutOfMemory
> message.
>
> Elapsed time  Memory Usage  Time to complete 10,000 loops
> ------------  ------------  -----------------------------
>  1 minute      26,108 K      31 seconds
> 20 minutes    121,696 K      70 seconds
> 54 minutes    185,132 K     116 seconds
>
> A similar memory increase and performance degradation is true running this
> program on a Linux Redhat 7.1 system with 256M memory and using IBM Java
> 1.3.0 (20010626) with the JIT on.
>
> However, on a Windows ME system with 64M memory using Sun Java 1.3.1
> (HotSpot), there is no increase in memory usage and no performance
> degradation, even after this program has run for 24 hours.
>
> Here's the code for the SimpleEmbedded Java program that's running:
>
> import org.python.util.PythonInterpreter;
> import org.python.core.*;
>
> public class SimpleEmbedded {
>
>     public static void main(String []args) throws PyException {
>
>         PythonInterpreter interp = new PythonInterpreter();
>
>         interp.exec("import time");
>         interp.exec("LoopStartTime = time.time()");
>
>         int i = 1;
>         while (i > 0)
>         {
>             interp.eval("'This is a test'");
>
>             if (i % 10000 == 0)
>             {
>                 interp.exec("LoopStopTime = time.time()");
>                 interp.exec("LoopElapsedSecs = LoopStopTime -
> LoopStartTime");
>                 System.out.println("Completed Loop " + i +
>                     " - elapsed time: " + interp.get("LoopElapsedSecs") +
>                     " secs");
>                 interp.exec("LoopStartTime = time.time()");
>             }
>             i++;
>        }
>
>     }
> }