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Subject: Re: [hwloc-users] Patch to disable GCC __builtin_ operations
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2011-06-08 17:21:47


Is there a reason we wouldn't disable it in OMPI's hwloc by default?

On Jun 8, 2011, at 5:14 PM, Josh Hursey wrote:

> 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/
>>
>>
>> _______________________________________________
>> hwloc-users mailing list
>> hwloc-users_at_[hidden]
>> http://www.open-mpi.org/mailman/listinfo.cgi/hwloc-users
>>
>>
>
>
>
> --
> Joshua Hursey
> Postdoctoral Research Associate
> Oak Ridge National Laboratory
> http://users.nccs.gov/~jjhursey
>
> _______________________________________________
> 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/