Sorry, I just saw that my response to you was off list.

In my experience, even giving java 4G (-l h_vmem=4G) isn't enough for
all but the most trivial jobs. Somehow java seems to size its memory
requests based on total available system memory and I have to allocate
ridiculous amounts of RAM to satisfy it. What tweaks do you use to make
java jobs run successfully?

Thanks,
Peter

On 08/29/2012 06:28 PM, Ian Kaufman wrote:
>> We found h_vmem to be highly unpredictable, especially with java-based
>> applications.  Stack settings were screwed up, certain applications wouldn't
>> launch (segfaults), and hard limits were hard to determine for things like
>> MPI applications.  When your master has to launch 1024 MPI sub-tasks (qrsh),
>> it generally eats up more VMEM than the slave tasks do.  It was just hard to
>> get right.
>>
>>
> Sadly, my users are using Java as well. Java and HPC do not mix very
> well, especially on 64 bit systems where a JVM will consume at least
> 4GB of RAM by default without mucking with any flags. Additionally,
> the crew I work with use a workflow/job management tool that isn't
> thread aware, so every child Java app that gets launched gets its own
> JVM. That is high on the list of things to fix!
>
> Ian
>

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