Re: [Condor-users] Understanding user priority and job preemption

[Jan Ploski <Jan.Ploski@xxxxxxxx>]

condor-users-bounces@xxxxxxxxxxx schrieb am 03/15/2007 04:53:16 PM:
> Jan Ploski wrote:
> > Today I analyzed my problem some more. In particular, I tested a 
variant 
> > without any nodes that don't match job requirements. That is, I tested 

> > with 20 rather than 60 total nodes.
> >
> > As before, user A has priority 4 and user B has priority 8.
> >
> > In the 20-node scenario, I can observe the following behavior:
> > 1. If user A submits jobs first, taking all machines, and user B comes 
in 
> > later, then user B does not get any machines - A's jobs are never 
> > preempted. User B does not get machines even if I remove some running 
jobs 
> > of user A. In this case A's jobs are preferred,
> > no matter what.
> > 
> 
> This is the scenario in which CLAIM_WORKLIFE should decrease the amount 
> of time it takes to balance out the share of the pool.  Without limiting 

> the lifespan of claims, it is expected that user A will retain 100% of 
> the pool in the case you describe.

Hmm... I think my tests were run with CLAIM_WORKLIFE = 1 and starvation 
still occurred. I will try again to be sure.

> > - Why is Condor assigning "pie slices" based on the total number of 
nodes 
> > in the pool rather than the total number of matching nodes?
> > 
> 
> The negotiator (as currently implemented) does not have a big list of 
> all the jobs from all the users.  It just has a list of submitters (i.e. 

> users), and it only ever considers one job at a time when making 
> matchmaking decisions.
> 
> > - Is there any way to achieve the expected 1:2 ratio between two users 

> > competing for N specific machines of a pool with a total size of M >= 
3*N?
> > 
> If you know in advance that users A and B will only ever be able to run 
> on N machines within your pool, then you could use group quotas to 
> specify their share of the N machines.

I will look into that. Thanks!

Best regards,
Jan Ploski

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