Re: [condor-users] preemption_requirements, once again

[Dan Bradley <dan@xxxxxxxxxxxx>]

Paulo Amado Mendes wrote:

> Despite some help provided by list members, I still don't understand 
> the behaviour of
> the PREEMPTION_REQUIREMENTS expression in our pool since we have upgraded
> to version 6.6.2 and, some days ago, to 6.6.4.
>
> We are using the following expression to avoid the pool being used 
> only by long
> running jobs:
> PREEMPTION_REQUIREMENTS    = $(ActivationTimer) < (5 * $(MINUTE)) \
>                            && RemoteUserPrio > SubmittorPrio * 1.5


How would this prevent your pool from being used by only long running 
jobs?  It looks to me like once a job is more than 5 minutes old, this 
expression prevents it from being preempted.

> It seems also that if a set of machines is claimed by a user with many 
> subprocesses,
> even if a subprocess finishes, that set of machines will only be 
> avalible for the same user. 


What you are seeing is the fact that there is no renegotiation of 
resources when a job happens to end.  A users claim to a machine lasts 
for as long as the schedd holds onto the claim (i.e. as long as there 
are more jobs to run) or until the claim gets preempted.

If you have preemption working, then this shouldn't be a problem for 
you.  If you don't have preemption working, or you don't want it to be 
working, then there are a few workarounds.  A feature being added to 
6.7.X will allow you to simply prevent preemption of jobs while still 
having preemption of claims (i.e. preemption on job boundaries).

--Dan


Condor Support Information:
http://www.cs.wisc.edu/condor/condor-support/
To Unsubscribe, send mail to majordomo@xxxxxxxxxxx with
unsubscribe condor-users <your_email_address>