I think we already do, but I can check
> On Sep 4, 2015, at 6:06 AM, Gilles Gouaillardet
> <gilles.gouaillar...@gmail.com> wrote:
>
> iirc, hwloc can read input from an xml file.
> if not already the case, should we provide a simple mechanism to tell hwloc
> not to detect the topology from the os but from a config file.
> for example, if working on a new os and/or hardware, then manually generate
> the hwloc xml file on each node and do something like
> mpirun --mca hwloc_file /etc/hwloc.xml ...
>
> makes sense ?
>
> On Friday, September 4, 2015, Ralph Castain <r...@open-mpi.org
> <mailto:r...@open-mpi.org>> wrote:
> It sounds, then, like removing —without-hwloc will do no harm. At worst,
> hwloc might report inaccurate info, but that won’t stop us from running with
> appropriate cmd line options (e.g., to set the #slots and bind-to none).
>
> Unless there are any further concerns, I’ll prep the PR
>
>
>> On Sep 4, 2015, at 1:08 AM, Kawashima, Takahiro <t-kawash...@jp.fujitsu.com
>> <javascript:_e(%7B%7D,'cvml','t-kawash...@jp.fujitsu.com');>> wrote:
>>
>> Brice,
>>
>> I'm a developer of Fujitsu MPI for K computer and Fujitsu
>> PRIMEHPC FX10/FX100 (SPARC-based CPU).
>>
>> Though I'm not familiar with the hwloc code and didn't know
>> the issue reported by Gilles, I also would be able to help
>> you to fix the issue.
>>
>> Takahiro Kawashima,
>> MPI development team,
>> Fujitsu
>>
>>> Thanks Brice,
>>>
>>> bottom line, even if hwloc is not fully ported, it should build and ompi
>>> should get something usable.
>>> in this case, i have no objection removing the --without-hwloc configure
>>> option.
>>>
>>> you can contact me off-list regarding the FX10 specific issue
>>>
>>> Cheers,
>>>
>>> Gilles
>>>
>>> On 9/4/2015 2:31 PM, Brice Goglin wrote:
>>>> Le 04/09/2015 00:36, Gilles Gouaillardet a écrit :
>>>>> Ralph,
>>>>>
>>>>> just to be clear, your proposal is to abort if openmpi is configured
>>>>> with --without-hwloc, right ?
>>>>> ( the --with-hwloc option is not removed because we want to keep the
>>>>> option of using an external hwloc library )
>>>>>
>>>>> if I understand correctly, Paul's point is that if openmpi is ported
>>>>> to a new architecture for which hwloc has not been ported yet
>>>>> (embedded hwloc or external hwloc), then the very first step is to
>>>>> port hwloc before ompi can be built.
>>>>>
>>>>> did I get it right Paul ?
>>>>>
>>>>> Brice, what would happen in such a case ?
>>>>> embedded hwloc cannot be built ?
>>>>> hwloc returns little or no information ?
>>>>
>>>> If it's a new operating system and it supports at least things like
>>>> sysconf, you will get a Machine object with one PUs per logical processor.
>>>>
>>>> If it's a new platform running Linux, they are supposed to tell Linux
>>>> at least package/core/thread information. That's what we have for ARM
>>>> for instance.
>>>>
>>>> Missing topology detection can be worked around easily (with XML and
>>>> synthetic description, what we did for BlueGene/Q before adding manual
>>>> support for that specific processor). Binding support can't.
>>>> And once you get binding, you get x86-topology even if the operating
>>>> system isn't supported (using cpuid).
>>>>
>>>>> for example, on Fujitsu FX10 node (single socket, 16 cores), hwloc
>>>>> reports 16 sockets with one core each and no cache. though this is
>>>>> not correct, that can be seen as equivalent to the real config by
>>>>> ompi, so this is not really an issue for ompi.
>>>>
>>>> Can you help fixing this?
>>>>
>>>> The issue is indeed with supercomputers with uncommon architectures
>>>> like this one.
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