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Subject: Re: [OMPI devel] Orte collectives
From: Richard Graham (rlgraham_at_[hidden])
Date: 2008-01-29 14:37:12


Sounds like xcast will do what I need.

If I don't pull data on all the procs, only the ones calling the recv, will
I basically create a memory leak ?

Thanks,
Rich

On 1/29/08 2:27 PM, "Ralph H Castain" <rhc_at_[hidden]> wrote:

> Depends upon which one you are using. For example, allgather operates across
> the entire job, so all procs in that jobid have to invoke it. On the other
> hand, allgather_list only operates across the procs specified in the list,
> so only they need to invoke it.
>
> Xcast sends a message to all procs in the job, but none of those procs needs
> to invoke anything - we just deliver the message to the specified RML tag on
> each proc. Of course, we assume that there is a recv (typically
> non-blocking) posted on that tag (or that it will be posted eventually). If
> not, then the message will just sit in the local oob waiting to be delivered
> - no harm done, it just gets ignored.
>
> Hope that helps. Let me know if you need some variant as I am adding (not
> reducing or changing) grpcomm capabilities on the tmp branch.
>
> Ralph
>
>
>
> On 1/29/08 12:19 PM, "Richard Graham" <rlgraham_at_[hidden]> wrote:
>
>> Are the group operations in ORTE (I assume this is what the grpcomm
>> component does) available to subsets of a job, or do all procs in the
>> orte_jobid_t need to invoke this ?
>>
>> Thanks,
>> Rich
>>
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>
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