[Pkg-openmpi-maintainers] Bug#502232: Bug#502232: Bug#502232: Bug#502232: Bug#502232: Bug#502232: libopenmpi-dev: No static libraries in the package

[Jeff Squyres]

Static libraries are definitely a Good Thing in some scenarios.  We  
have a few features in this arena, which we consider separately:

- building libmpi (and friends) as .a instead of .so
- slurping all the plugins into libmpi (and friends) instead of  
creating them as standalone DLLs
- disabling dlopen altogether

When someone says "building static", they usually mean enabling all 3  
of those options.  This can be really helpful for running massive  
scale MPI jobs, for example.  It also helps decrease complexity by  
decreasing the number of run-time variables for problematic or  
production environments.  In short, we recognize that everyone has  
different requirements, so we try to enable everyone to do what they  
need.

So yes, we believe that building statically is a Good Thing.  But by  
default, we disable all of those options and build everything  
dynamically because it's the most flexible and results in the smallest  
user MPI executables.  That is the "usual" case that users care  
about.  Make sense?

Building statically is certainly an option; I confess to not knowing  
enough about deb's to know if you can embed conditional logic in there  
to build dynamically if the user doesn't specify anything, or enable  
some/all of the 3 above features if requested.  E.g., RPM's have a  
kinda kludgey way to pass in build options.

However, keep in mind that compiling statically with OpenFabrics adds  
an unfortunate new dimension of complexity in terms of creating fully- 
static MPI libraries and applications:

     http://www.open-mpi.org/faq/?category=openfabrics#ib-static-mpi- 
apps

For this reason, we don't usually recommend static building -- you  
really have to know and understand what you're doing.  Most users  
aren't willing to go to this level of effort for static; that's really  
the only reason that the FAQ says that static linking is "not  
recommended."


On Oct 15, 2008, at 11:15 AM, Gary Hennigan wrote:

> Dirk Eddelbuettel wrote:
>> On 15 October 2008 at 08:43, Dirk Eddelbuettel wrote:
>> | We had request by a Gary from Sandia about providing static libs,  
>> which we
>>
>> Yeepers. Not sure how that pejorative 'a' landed in there. My  
>> apologies to Gary!
>>
> Well, while I consider myself important I'd feel even worse if you  
> had written *THE*. ;) No worries!
>
> One other thing, while it would be convenient for me to have this  
> feature in the Debian package it is by no means a show stopper. As  
> you pointed out I can easily build the static libraries myself and  
> get my work done. That's also why I filed it as a "wishlist" item. I  
> didn't want you guys prioritizing this because of one whiny guy. I  
> just wanted to bring it to your attention and let you decide how you  
> wanted to prioritize it.
>
> That said, I appreciate all the work you've already done on  
> packaging OpenMPI for Debian and for the time you've spent bouncing  
> my request around. Thanks!
>
> Gary
>
>


-- 
Jeff Squyres
Cisco Systems