Re: [condor-users] Questions about resource allocation and user priorites...

[Dan Bradley <dan@xxxxxxxxxxxx>]

Jonathan Giddy wrote:

> > Michael S. Root wrote:
> >
> >    
> >
> > > The thing is, the individual jobs that make up each dag usually only take
> > > between 1 and 20 minutes each, but there can be several hundred jobs per
> > > dag.  Why don't the second user's jobs acquire resources as the first
> > > user's dag's individual "sub-jobs" finish, which they do fairly often?
> > >      
> > Currently, there is no way to tell Condor you want preemption of
> > resource claims to be considered between job boundaries.  However, you
> > _can_ set PREEMPTION_REQUIREMENTS to allow preemption during the first
> > few minutes of a job's life, instead of the default expression which is
> > to allow preemption after the claim has existed for one hour:
> >    
>
> When a job completes, the machine returns to the Claimed/Idle state, where
> the START expression is checked before a new job for the user is started.
>
> So I add the following to my START expression:
>
> START = $(START) && ( State != "Claimed" || $(StateTimer) < 30 * $(MINUTE) )
>
> If the machine has been in the Claimed state for more than half an hour (a
> sign that at least one job has been run for the user), this evaluates to
> False and the Machine is returned to the Unclaimed state, where it can be
> matched to any user.

Very good point!

The effect of this is to relinquish the user's claim after 30 minutes 
when a job finishes (whether or not anybody else is in line to use the 
machine).  For a user with a lot of jobs in the queue, you will see a 
little more latency, since the claim will need to be re-established each 
time.  This delay will be on the order of a negotiation cycle--about 5 
minutes by default.  On the positive side, you get potentially faster 
reallocation of resources without any additional jobs being killed.

Dan Bradley


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