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Subject: Re: [OMPI users] Number of processes and spawn
From: Federico Golfrè Andreasi (federico.golfre_at_[hidden])
Date: 2010-03-01 05:51:25


Ok, thank you !

where can I found instructions for download the developer's copy of OpenMPI,
if it is possibile?

I'd like to test it just to be sure that the problem is solved, with that
patch.

Can you let me know where that patch is available?

Thank you very much,

Federico

2010/2/27 Ralph Castain <rhc_at_[hidden]>

> Okay, thanks. It's the same problem as the other person encountered.
> Basically, it looks to OMPI as if you are launching > 128 independent app
> contexts, and our arrays were limited to 128.
>
> He has provided a patch that I'll review (couple of things I'd rather
> change) and then apply to our developer's trunk. I would expect it to
> migrate over to the 1.4 release series at some point (can't guarantee which
> one).
>
>
> On Feb 27, 2010, at 6:47 AM, Federico Golfrè Andreasi wrote:
>
> Hi,
>
> the program is executed as one application on 129 cpus defined by the
> hostfile.
> Than rank 0, inside the code, execute another program with 129 cpus, with a
> one-to-one relation, rank0 of the spawined process runs on the same host of
> rank0 of the spawning one and so on...
> Excuting the spawning program does not give any problem,
> but in the moment of spawning (with more than 128 cpus) it holds.
>
> Thank you!
>
> Federico
>
>
>
>
> 2010/2/27 Ralph Castain <rhc_at_[hidden]>
>
>> Since another user was doing something that caused a similar problem,
>> perhaps we are missing a key piece of info here. Are you launching one
>> app_context across 128 nodes? Or are you launching 128 app_contexts, each on
>> a separate node?
>>
>>
>> On Feb 26, 2010, at 10:23 AM, Federico Golfrè Andreasi wrote:
>>
>> I'm doing some tests and it seems that is not able to do a spawn multiple
>> with more than 128 nodes.
>>
>> It just hold, with no error message.
>>
>> What do you think? What can I try to understand the problem.
>>
>> Thanks,
>>
>> Federico
>>
>>
>>
>>
>> 2010/2/26 Ralph Castain <rhc_at_[hidden]>
>>
>>> No known limitations of which we are aware...the variables are all set to
>>> int32_t, so INT32_MAX would be the only limit I can imagine. In which case,
>>> you'll run out of memory long before you hit it.
>>>
>>>
>>> 2010/2/26 Federico Golfrè Andreasi <federico.golfre_at_[hidden]>
>>>
>>>> HI !
>>>>
>>>> have you ever did some analysis to understand if there is a limitation
>>>> in the number of nodes usable with OpenMPI-v1.4 ?
>>>> Using also the functions MPI_Comm_spawn o MPI_Comm_spawn_multiple.
>>>>
>>>> Thanks,
>>>> Federico
>>>>
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