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Subject: Re: [OMPI users] After OS Update MPI_Init fails on one host
From: Ralph Castain (rhc_at_[hidden])
Date: 2013-07-23 08:54:19


On Jul 23, 2013, at 3:56 AM, Jeff Squyres (jsquyres) <jsquyres_at_[hidden]> wrote:

> On Jul 21, 2013, at 8:50 AM, Kevin H. Hobbs <hobbsk_at_[hidden]> wrote:
>
>>> Ah! That would indicate an issue with the external hwloc
>>> package they provided, which is the big reason we don't
>>> recommend installing from packages.
>>
>> I'll happily report the bug to the hwloc developers.
>
> I don't think that this is necessarily an hwloc bug.
>
>> I'll also add what we've found here to the bug on the Fedora
>> bugzilla.
>>
>> Is there anything more I can do on this list to figure out the
>> nature of the bug?
>>
>>> We have internal copies of hwloc and libevent that ensure (a)
>>> they are at the proper level, and (b) they are configured
>>> properly for OMPI's use.
>>
>> It does look like Fedora's hwloc is ahead of OMPI's.
>>
>> Fedora 18 has openmpi-1.6.3 and hwloc-1.4.2.
>>
>> The source of openmpi-1.6.5 has hwloc-1.3.2.
>
> Hypothetically, hwloc 1.4.x is backwards source-compatible with hwloc 1.3.x, but we have not tested this. I don't know if hwloc has, either (I'm sure they haven't tested with Open MPI 1.6.x).
>
>> How can I tell what the configuration differences are?
>>
>> The entire configure section of the .spec file in
>> hwloc-1.4.2-2.fc18.src.rpm is :
>>
>> %configure
>> %{__make} %{?_smp_mflags} V=1
>
> OMPI builds hwloc in "embedded" mode, which means that OMPI's configure line is used to build hwloc (vs. having a separate configure invocation for hwloc). They're hypothetically the moral equivalent of each other, but perhaps something is different somehow...
>
>> I don't see anything that looks like any hwloc configure options
>> are being set.
>>
>> How do I tell how OMPI configures it's bundled hwloc?
>
> With this embedded mechanism, we're calling hwloc's configury with the moral equivalent of:
>
> ./configure --disable-cairo --disable-libxml2 --enable-xml --with-hwloc-symbol-prefix=opal_hwloc152_ --enable-embedded-mode
>
>> Better yet, I'd like to figure out the actual nature of the bug
>> and report it in the proper place.
>
>
> Yes, it's curious that they can't reproduce your issue,

Guess I missed this - where does it say that they can't reproduce the issue?? I'm suspicious because build-from-source produced a working result.

> which suggests that the hwloc issue is a red herring (because, as stated above, hwloc *should* be backwards compatible).
>
> Ralph: is there an easy way to find out more detail on why orte_util_nidmap_init() failed without attaching a debugger?

A debugger would be the best way.

>
> --
> Jeff Squyres
> jsquyres_at_[hidden]
> For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/
>