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Subject: Re: [hwloc-users] Patch to disable GCC __builtin_ operations
From: Josh Hursey (jjhursey_at_[hidden])
Date: 2011-06-08 17:14:14


In short, I haven't yet. I figured out the problem was in hwloc, and
started with the hwloc branch by itself.

In Open MPI, we should be able to pass the --disable-gcc-builtin from
the main configure, right (since we pull in config/hwloc_internal.m4)?
So we would pass it similar to how we had to pass --disable-xml to
turn off that feature in the builtin hwloc (before it was turned off
by default).

-- Josh

On Wed, Jun 8, 2011 at 4:50 PM, Jeff Squyres <jsquyres_at_[hidden]> wrote:
> Josh --
>
> How did you get this disabled from within OMPI?  We don't invoke hwloc's configure via sub-shell; we directly invoke its m4, so we don't have an opportunity to pass --disable-gcc-builtin.  Unless you passed that to the top-level OMPI configure script...?
>
>
> On Jun 8, 2011, at 4:28 PM, Josh Hursey wrote:
>
>> (This should have gone to the devel list)
>>
>> The attached patch adds a configure option (--disable-gcc-builtin) to
>> disable the use of GCC __builtin_ operations, even if the GCC compiler
>> supports them. The patch is a diff from the r3509 revision of the
>> hwloc trunk.
>>
>> I hit a problem when installing hwloc statically on a machine with a
>> slightly different gcc support libraries and OSs on the head/compile
>> node versus the compute nodes. The builtin functions would cause hwloc
>> to segfault when run on the compute nodes. By disabling the builtin
>> operations, and using the more portable techniques seemed to do the
>> trick.
>>
>> This problem first became apparent when using hwloc as part of Open
>> MPI. In Open MPI the mpirun process runs on the headnode, so the hwloc
>> install would work in the mpirun process but cause the compute
>> processes to segv.
>>
>> Can you review the patch, and apply it to the trunk? Once the patch is
>> in the trunk, then I'll work on the Open MPI folks to update their
>> revision.
>>
>> Thanks,
>> Josh
>>
>> --
>> Joshua Hursey
>> Postdoctoral Research Associate
>> Oak Ridge National Laboratory
>> http://users.nccs.gov/~jjhursey
>> <hwloc-diff-r3509.diff>_______________________________________________
>> hwloc-users mailing list
>> hwloc-users_at_[hidden]
>> http://www.open-mpi.org/mailman/listinfo.cgi/hwloc-users
>
>
> --
> Jeff Squyres
> jsquyres_at_[hidden]
> For corporate legal information go to:
> http://www.cisco.com/web/about/doing_business/legal/cri/
>
>
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> hwloc-users_at_[hidden]
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>
>

-- 
Joshua Hursey
Postdoctoral Research Associate
Oak Ridge National Laboratory
http://users.nccs.gov/~jjhursey