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Re: [argouml-users] Heap limits in OS X

Author tfmorris
Full name Tom Morris
Date 2011-09-14 19:58:16 PDT
Message Hi Jack. It's been a while since I coded this up, but

On Wed, Sep 14, 2011 at 8:53 PM, Jack Repenning <jrepenning at collab dot net> wrote:

> Contents/Info.plist includes a dict key [Java][VMOptions] that contains an -Xmx value, so I changed that and restarted ArgoUML … but it doesn't seem like the change had the expected effect: I set it to 1024M, but the little heap indicator in the bottom right of the main window is saying "503M used of 600M total" and showing a warning orange band.
> I suppose a "warn at 500 for a limit of 600" is not unduly alarmist … but I gave it 1024, not just 600, why's it whining at me?

I hope it's not whining too loudly, but, as I remember it, the orange
line limit is arbitrary (ie picked out of the air by me) and full
scale on the graph is the *current* (not max) heap size. Typical JVM
behavior is for heap allocations to ratchet up towards some limit
(e.g. 90% of the current heap) which triggers a garbage collection and
when heap usage stays too close to the total heap size for a period of
time to increase the size of the heap (by asking the O/S for more
memory) and, finally, when the heap has been expanded as much as
possible, to give an OutOfMemory error.

> Should I have set this elsewhere? Should I adjust my execrations? Are there things (like, say, extensions) I can remove to free some heap?
> And, is this heap usage reasonable? I only have one diagram (a Sequence diagram), with four Classifiers, and 22 Actions.

Pretty much impossible to say without more info. If that's 500 MB out
of 600 MB, of which, 250 MB could be garbage collected if needed, I'd
say it's not an issue. There used to be a menu command to force a
garbage collection, but I'm not sure it's still there. Even if it is,
it's really only a way to establish a benchmark of actual heap usage
-- it's not a way to reduce memory usage or improve efficiency.

The real warning size to watch for is that the heap indicator, instead
of going from 90% to 50% continually, stays pegged at 90%+ (which will
also mean that you've maxed out your heap expansion opportunities.

With the limited time I have available to commit, I'm much more
focused on ArgoEclipse than ArgoUML, but I'd be happy to tweak the
current implementation of the heap monitor dispaly if folks can come
up with a consensus for a more valuable display (e.g. don't show the
alarming orange color at whatever the threshold is set at).


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[argouml-users] Heap limits in OS X jrepenning Jack Repenning 2011-09-14 17:53:42 PDT
     Re: [argouml-users] Heap limits in OS X tfmorris Tom Morris 2011-09-14 19:58:16 PDT
         Re: [argouml-users] Heap limits in OS X tfmorris Tom Morris 2011-10-03 20:13:54 PDT
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