[torqueusers] Semaphores limit per job/user in torque?

Andrew Savchenko bircoph at gmail.com
Mon Sep 23 11:19:02 MDT 2013

Hello David,

On Mon, 23 Sep 2013 09:56:13 -0600 David Beer wrote:
> Andrew,
> Can you be more specific about what you mean when you say semaphores?

I mean System V IPC semaphores, they can be seen via ipcs -s and
their system wide limit is controlled via /proc/sys/kernel/sem.

> On Sat, Sep 21, 2013 at 3:09 PM, Andrew Savchenko <bircoph at gmail.com> wrote:
> > Hello,
> >
> > is it possible to limit or isolate semaphores per job or user at
> > worker node in torque?
> >
> > At our cluster we have a problem with buggy user jobs which left
> > semaphores behind leading to semaphore limit exhaustion. While limit
> > may be lifted, this is not a proper solution since it will be reached
> > again later. ATM we a running cron job using some heuristics to
> > determine which semaphores are safe to clear. But this is still
> > nothing but a workaround.
> >
> > The proper way is to isolate job or at least user IPC namespace on
> > nodes. This can be done using IPC namespace kernel feature, though I
> > don't know if torque is capable of this or any other ways to control
> > job's IPC.
> >
> > ATM we're using torque-3.0.6, though if 4.x branch is capable of this
> > feature, it will be a good reason to migrate.

Best regards,
Andrew Savchenko
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