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From "Weldon Washburn" <weldon...@gmail.com>
Subject Re: Stack Overflow Error support issues
Date Wed, 26 Jul 2006 18:41:11 GMT
On 7/26/06, Gregory Shimansky <gshimansky@gmail.com> wrote:
> On Wednesday 26 July 2006 20:05 Rana Dasgupta wrote:
> > In general, I am not too keen to implement a feature to mitigate a bug. I
> > also think that we need some real usage based test cases for SOE failure (
> > not our dev tests for unbounded recursion which force it to happen )
> > to understand how serious the problem is in usage scenarios. Most server
> > environments eg., web servers, recycle host processes, so I have some
> > doubts on how often this kind of resource scarcity problem really occurs.
> > Thread stacks are also not shared resources, even on clients. Anyway, we
> > may want to wait till Harmony identifies some signature apps or benchmarks
> > and we see failures due to SOE. In the meantime, my suggestion/vote would
> > be to proactively check for exception state in unwindable code sections in
> > the jit, or when returning from suspension state in the VM. That would be
> > my 2 cents.
>
> To make SOE more likely to happen in real applications it is easy to
> use "ulimit -s" command to limit the stack size to some small value. The
> default on Linux is 8Mb which is quite a lot.

All good points.  Forcing the JVM into an SOE condition, then
analyzing what happens is a valuable tool.  However, it is more
important to know when/where the JVM runs into SOE problems with real
workloads.  And what we need to do to address this particular
situation.  While it is conceivable that real workloads could cause
substantial redesign to make SOE work as expected, we need to be
convinced this is indeed the situation.  In other words, premature
overengineering is the little brother of premature optimization.

>
> Both drlvm and Sun VM honor this stack limit and it is possible to make even
> the very simple applications to fail on stack shortage or even crash the VM
> (Sun crashes too) when stack is very small like 32Kb.
>
> Also playing with ulimit -s it is possible to try to catch situations when SOE
> happens in VM code like in JIT or class loader.
>
> --
> Gregory Shimansky, Intel Middleware Products Division
>
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>


-- 
Weldon Washburn
Intel Middleware Products Division

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