[Mauiusers] Re: maui not schedulling jobs in avaliable resources

Brian Christiansen bchristiansen at clusterresources.com
Thu Mar 26 10:22:15 MDT 2009


Roy, or anyone else seeing this,

I'm trying to reproduce the behavior that you are seeing and haven't 
been successful. Could you give me some tips, or send me your maui.cfg?


Roy Dragseth wrote:
> On Thursday 19 March 2009 00:23:02 Brian Christiansen wrote:
>   
>> Roy,
>>
>> Thinking about the issue, it seems like backfill is not working. I would
>> expect that once maui hits the maxijob limit, maui would quit making
>> priority reservations in MQueueScheduleIJobs and then perform backfill
>> (MQueueBackFill) on the jobs that do have available resources to run.
>> Could this be what you are seeing?
>>     
>
> I have no idea, you're pushing me towards the edge of my competence here...
>
> Anyhow I cannot see why it should need to backfill when there are nodes without 
> reservations on them available.  Isn't it so that it should try to first 
> schedule the jobs that have a priority reservation, then backfill with as many 
> jobs as  possible and then schedule any other idle jobs?
>
> r.
>
>   
A maui scheduling iteration:

1) Schedule Suspended and Reserved Jobs
2) Schedule Idle priority jobs
3) Backfill

A quick scenario:
4 nodes 1 proc each.

Submit 3, 1 node 10 minute, jobs.
Submit 1, 4 node 10 minute, job
Maui starts the first 3 and the 4th sits idle with a reservation.

For a job to run on the one available node, a job must be able to 
complete before the 4 node job starts. showbf will you show how much 
time is available.

Submit 2, 1 node 10 minute, jobs. This should trigger the Idle Job 
Reached area of the code (can see in the logs). The 4 node job isn't 
considered because it already has a reservation, the second idle job 
can't get a reservation because of the 4 node job's reservation, and the 
third idle job isn't considered because the IdleJobFound is set.

Submit 1, 1 node 1 minute, job. This job won't be considered during idle 
priority job scheduling because IdleJobFound is set by the time it looks 
at the job, but will be backfilled because it fits in the available 
window before the 4 node job should start.

Hope this helps.

Thanks,
Brian



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