[Mauiusers] Urgent jobs

David Jackson jacksond at clusterresources.com
Sat Apr 2 09:26:01 MST 2005


  Thanks for responding.  On behalf of the Maui gurus, we apologize for
being so non-responsive.  We are swamped like you wouldn't believe.  We
keep hiring people but we can't keep up!  We are very happy about all
the growth but we apologize we are stretched thin on some fronts.

  Regarding the question, would there be the possibility of using
TORQUE/OpenPBS's virtual processors ('np' attribute) to set the absolute
maximum bound per node and use standing reservations to reserve a
portion of these virtual processors for use only by 'special' jobs.  For
example, for each node you could set the number of virtual processors to
8.  You could then create a standing reservation with a CLASSLIST ACL of
'short' which reserved 4 of those 8 nodes exclusively for 'short' jobs.
Thus, normal jobs could use up to 4 processors, short jobs could use up
to 8 processors, and the total of all jobs would also be limited to 8

  Would this work?  Please let us know how things go.


On Sat, 2005-04-02 at 10:42 -0500, Yaroslav Halchenko wrote:
> Hi Torsten,
> Because all maui gurus seems to keep respectable silence, I will try to
> help you at least the way I solved similar problem.
> I'm pretty sure that dynamic extension of maxload is not possible and I
> didn't succeed with seting up timeshared nodes... So what I've done is
> simple
> double number of available CPUs, ie np=2*realcpunumber for each node
> set queue main max_running = nodes*realcpunumber
> set queue short max_running = nodes*realcpunumber
> and in maui choose nodes by the job count:
> so I favor fast jobs
> such method is far from being optimal because in some cases you can get
> more than realcpunumber jobs on the same host, which you dont' want. but
> if regularly you run long jobs in main and short in short then such
> non-desired scheduling is rare
> I would be glad to hear any better ideas
> -- 
> Yarik
> On Thu, Mar 31, 2005 at 06:23:48PM +0200, Torsten Wolf wrote:
> > My first guess was, to divide the nodes into one half of exclusive nodes
> > and another half of timeshared nodes. Then I could use loadleveling with
> > a value of 2 per node and would have the same behaviour on the system as
> > before. But with this I hoped that, I could create a queue/scheduler
> > policy which allows me to extend the maximum load for such urgent jobs.
> > A user would request 5 minutes in that special queue, the maximim load
> > would be increased to e.g. 4 and his job could start at once. Yes, there
> > should be an upper load limit, so that the machine is not flooded by
> > such jobs. But actually, I have no idea how to do this with OpenPBS. The
> > ideal and maximum load is configured per mom and cannot be altered by
> > queues/jobs.
> > So I came across to Maui and would like to know, if this scheduler would
> > fit my needs. Or can this be achieved even with the scheduler shipped
> > with OpenPBS? Hopefully, I have not bothered you too much.
> > Best wishes,
> > Torsten
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> > mauiusers at supercluster.org
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