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Subject: Re: [OMPI devel] Component open
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2008-10-23 10:09:22


FWIW, this turned out to be a combination of two things:

1. Ralph's experimental DSO's were referencing a missing symbol,
causing the underlying dlopen() to fail

2. LT 2.2.6 is incorrectly (IMHO) reporting "file not found" instead
of "missing symbol" through lt_dlerror(), which is darned confusing
(because you look at the filesystem and say, "but the file is
there!!"). I have posted to the LT bug mailing list about it:

     http://lists.gnu.org/archive/html/bug-libtool/2008-10/msg00017.html

On Oct 22, 2008, at 3:36 PM, Ralph Castain wrote:

> Hmmm...interesting. I see what's going on - I'm having a build
> system issue that is causing some of the dynamic libraries to not be
> seen.
>
> Red herring - thanks for clarifying!
>
> Camille: thanks for fixing this way back when.
>
> Ralph
>
>
> On Oct 22, 2008, at 1:17 PM, George Bosilca wrote:
>
>> Ralph,
>>
>> This problem was fixed long ago by some of the work Camille did.
>> The exact revision number is r15402 (https://svn.open-mpi.org/trac/ompi/changeset/15402
>> ). I'm using this feature daily and so far I had any problems with
>> it.
>>
>> To reuse your example here is what Camille came up with.
>>
>> $ mpiexec --mca routed_base_verbose 30 -n 3 hostname
>> [dancer:09638] mca: base: components_open: Looking for routed
>> components
>> [dancer:09638] mca: base: components_open: opening routed components
>> [dancer:09638] mca: base: components_open: found loaded component
>> binomial
>> [dancer:09638] mca: base: components_open: component binomial has
>> no register function
>> [dancer:09638] mca: base: components_open: component binomial has
>> no open function
>> [dancer:09638] mca: base: components_open: found loaded component
>> direct
>> [dancer:09638] mca: base: components_open: component direct has no
>> register function
>> [dancer:09638] mca: base: components_open: component direct has no
>> open function
>> [dancer:09638] mca: base: components_open: found loaded component
>> linear
>> [dancer:09638] mca: base: components_open: component linear has no
>> register function
>> [dancer:09638] mca: base: components_open: component linear has no
>> open function
>> [dancer:09638] mca:base:select: Auto-selecting routed components
>> [...]
>>
>> And if we force a special component:
>>
>> $ mpiexec --mca routed linear --mca routed_base_verbose 30 -n 3
>> hostname
>> [dancer:09642] mca: base: components_open: Looking for routed
>> components
>> [dancer:09642] mca: base: components_open: opening routed components
>> [dancer:09642] mca: base: components_open: found loaded component
>> linear
>> [dancer:09642] mca: base: components_open: component linear has no
>> register function
>> [dancer:09642] mca: base: components_open: component linear has no
>> open function
>> [dancer:09642] mca:base:select: Auto-selecting routed components
>> [...]
>>
>> I wonder what are the configuration options you're using?
>>
>> george.
>>
>> On Oct 22, 2008, at 1:30 PM, Ralph Castain wrote:
>>
>>> I've been digging a little into optimization and found something
>>> that seems counterintuitive in the way OMPI is handling
>>> components. Specifically, if I specify a component I want used for
>>> a framework, OMPI still does a component load and open on every
>>> component in the framework - it only uses my specification during
>>> "select".
>>>
>>> Thus, the cmd line
>>>
>>> mpirun -mca routed linear
>>>
>>> still results in the loading and opening of the direct and
>>> binomial components - even though we have directed the framework
>>> not to use them.
>>>
>>> This causes us to waste memory when there is no possibility of a
>>> different component being selected. Is there a reason why "open"
>>> isn't using the mca params to guide the components it is loading?
>>>
>>> Ralph
>>>
>>> _______________________________________________
>>> devel mailing list
>>> devel_at_[hidden]
>>> http://www.open-mpi.org/mailman/listinfo.cgi/devel
>>
>> _______________________________________________
>> devel mailing list
>> devel_at_[hidden]
>> http://www.open-mpi.org/mailman/listinfo.cgi/devel
>
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-- 
Jeff Squyres
Cisco Systems