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Subject: Re: [OMPI devel] MCA component open
From: Josh Hursey (jjhursey_at_[hidden])
Date: 2008-05-02 16:40:50


We could also call it 'null' for the empty set of components? Or maybe
OMPI-NULL.

Outside of the naming do others this this is a useful feature to
implement?

-- Josh

On May 2, 2008, at 10:51 AM, Ralph Castain wrote:

> I would think that adding a special keyword would be the correct
> method. I
> would suggest something with an "ompi" in it, perhaps capitalized so
> there
> is no confusion...something like "OMPI-NONE"?
>
>
> On 5/2/08 8:37 AM, "Josh Hursey" <jjhursey_at_[hidden]> wrote:
>
>> I don't believe we have the logic in place to tell mca_component_open
>> 'do not open anything'. (I could be wrong though).
>>
>> Adding such an option might be useful, but we would have to consider
>> how that option should be specified by the user. Currently if you do
>> not set a value (leave empty space in mca-params.conf) then the MCA
>> system takes this to indicate that all components are eligible for
>> selection. If you specify any options then only those options should
>> be opened. We could add a special keyword (such as 'none') to
>> indicate
>> 'open nothing'.
>>
>> What do people think about that?
>>
>> -- Josh
>>
>>
>> On May 2, 2008, at 10:22 AM, Ralph Castain wrote:
>>
>>> I see what the problem is. In the case of slurm, I don't want -any-
>>> components to be opened, even though I am going to call plm open/
>>> select. I
>>> have to leave that logic in place for those environments that -do-
>>> want to
>>> specify some backend secondary launcher.
>>>
>>> So the question is: how do I tell mca_component_open "do not open
>>> anything"?
>>>
>>> If we don't have a mechanism for doing that, can we create one?
>>>
>>>
>>> On 5/2/08 8:02 AM, "Ralph Castain" <rhc_at_[hidden]> wrote:
>>>
>>>> Well, I have a current version of the trunk. I add an MCA param to
>>>> the
>>>> environment indicating that only rsh is to be used by the orted.
>>>> Yet I get
>>>> an output from every orted indicating that slurm (misspelled!) is
>>>> available
>>>> for selection.
>>>>
>>>> This tells me that the slurm component is being opened, even though
>>>> the
>>>> param is set.
>>>>
>>>> I can check again to ensure that the param is set...
>>>>
>>>>
>>>> On 5/2/08 7:53 AM, "Jeff Squyres" <jsquyres_at_[hidden]> wrote:
>>>>
>>>>> (moving to devel list for wider audience)
>>>>>
>>>>> Hmm. I thought the UTK stuff from a while ago supposedly changed
>>>>> this
>>>>> behavior to only open the components that were specifically
>>>>> requested.
>>>>>
>>>>> This behavior looks like the *original* MCA behavior -- open them
>>>>> all,
>>>>> then discard what we don't want (but doesn't necessarily reclaim
>>>>> the
>>>>> memory because of how dlclose works).
>>>>>
>>>>>
>>>>> On May 2, 2008, at 9:48 AM, Ralph Castain wrote:
>>>>>
>>>>>> Yo guys
>>>>>>
>>>>>> I've noticed something on the trunk that just doesn't strike me
>>>>>> as
>>>>>> correct.
>>>>>> If I specify "-mca plm rsh", it is my expectation that (a) only
>>>>>> the
>>>>>> rsh
>>>>>> component will be opened, and (b) only the rsh module will be
>>>>>> selected,
>>>>>> unless that component indicates that it cannot run.
>>>>>>
>>>>>> What I am seeing, though, is that -all- the plm components are
>>>>>> being
>>>>>> opened.
>>>>>> This is not only unnecessary, but consumes memory and leads to
>>>>>> concern over
>>>>>> whether or not some other module could become active.
>>>>>>
>>>>>> Is this the intended behavior? If so, may I suggest we change
>>>>>> it in
>>>>>> Josh's
>>>>>> branch prior to bringing it over?
>>>>>>
>>>>>> Ralph
>>>>>>
>>>>>>
>>>>>
>>>>
>>>>
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>>>
>>>
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