[petsc-dev] [buildsystem] support for --start-group/--end-group

[Matthew Knepley]

On Mon, Apr 11, 2011 at 2:02 AM, Chen Shen <hashhsah at gmail.com> wrote:

> Hi all,
>
> Currently, there is an option to specify the blas/lapack library
> files --with-scalapack-lib=[<list of .a files>]. This is indeed necessary,
> because MKL provides a large choice of libraries to link against.
>
> However, MKL static libraries have object inter-dependencies, and requires
> --start-group/--end-group linker options. All libraries in the group are
> searched repeatedly until all inter-dependencies resolved.
> For example, the following options is suggested for a configuration (
> http://software.intel.com/en-us/articles/intel-mkl-link-line-advisor/):
>
> $(MKLROOT)/lib/intel64/libmkl_scalapack_lp64.a  -Wl,--start-group
> $(MKLROOT)/lib/intel64/libmkl_intel_lp64.a
> $(MKLROOT)/lib/intel64/libmkl_sequential.a
> $(MKLROOT)/lib/intel64/libmkl_core.a
> $(MKLROOT)/lib/intel64/libmkl_blacs_intelmpi_lp64.a -Wl,--end-group
> -lpthread
>
> I'd like to propose an extension to the --with-scalapack-lib syntax to
> support start/end group. Consider the following example:
> --with-blas-lapack-lib=[ /xxx/scalapack_lp64.a,
> [/xxx/libmkl_intel_lp64.a, /xxx/libmkl_sequential.a, libmkl_core.a,
> /xxx/libmkl_blacs_intelmpi_lp64.a] ]
>
> The embedded list indicates a set of libraries to be grouped up. Would this
> be possible?
>

Is there a problem with just including these options in the list of
libraries? I think we keep anything that begins with a '-'.

  Thanks,

     Matt


> This isn't a problem if we link to dynamic libraries, because -l for
> dynamic libraries doesn't have to be ordered as in the case of static
> libraries.
> I hate the wicked order rule for .a libraries, but have to live with it...
>
> Further, I guess -Bstatic options are dropped somewhere (I haven't checked
> it in detail). The final PACKAGES_LIBS macro never contains -Bstatic, so end
> application will always link to the static libraries.
>
>
> Regards,
> Shen Chen
>
>
>


-- 
What most experimenters take for granted before they begin their experiments
is infinitely more interesting than any results to which their experiments
lead.
-- Norbert Wiener
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