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Subject: Re: [OMPI users] Spawn_multiple with tight integration to SGE grid engine
From: Reuti (reuti_at_[hidden])
Date: 2012-01-31 05:02:19


Am 31.01.2012 um 06:33 schrieb Rayson Ho:

> On Mon, Jan 30, 2012 at 11:33 PM, Tom Bryan <tombry_at_[hidden]> wrote:
>> For our use, yes, spawn_multiple makes sense. We won't be spawning lots and
>> lots of jobs in quick succession. We're using MPI as an robust way to get
>> IPC as we spawn multiple child processes while using SGE to help us with
>> load balancing our compute nodes.
>
> Note that spawn_multiple is not going to buy you anything as SGE and
> Open Grid Scheduler (and most other batch systems) do not handle
> dynamic slot allocation. There is no way to change the number of slots
> that are used by a job once it's running.

Agreed, the problem is first to phrase it in a submission command like: I need 2 cores for 2 hours, 4 cores for one hour and finally 1 core for 8 hours. And the application must act accordingly. This all sounds more like a real-time queuing system and application, where this can be ensured to happen in time.

-- Reuti

> For this reason, I don't recall seeing any users using spawn_multiple
> (and also, IIRC, the call was introduced in MPI-2)... and you might
> want to make sure that normal MPI jobs work before debuging a
> spawn_multiple() job.
>
> Rayson
>
> =================================
> Grid Engine / Open Grid Scheduler
> http://gridscheduler.sourceforge.net/
>
> Scalable Grid Engine Support Program
> http://www.scalablelogic.com/
>
>
>>
>>> Anyway:
>>> do you see on the master node of the parallel job in:
>>
>> Yes, I should have included that kind of output. I'll have to run it again
>> with the cols option, but I used pstree to see that I have mpitest --child
>> processes as children of orted by way of sge_shepherd and sge_execd.
>>
>> Thanks,
>> ---Tom
>>
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>
>
>
> --
> Rayson
>
> ==================================================
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> http://gridscheduler.sourceforge.net/
>
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