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Subject: Re: [OMPI devel] GROUP_EMPTY fixes break intel tests :-(
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2007-12-06 13:46:42


Done: r16872.

On Dec 6, 2007, at 1:34 PM, Terry Dontje wrote:

>
> Jeff Squyres wrote:
>> I should also note the following:
>>
>> - LAM/MPI does the same thing (increments refcount when GROUP_EMPTY
>> is
>> returned to the user, and allows GROUP_EMPTY in GROUP_FREE)
>>
>> - MPICH2 has the following comment in GROUP_FREE (and code to match):
>>
>> /* Cannot free the predefined groups, but allow
>> GROUP_EMPTY
>> because otherwise many tests fail */
>>
>> So I'm thinking that we should allow GROUP_EMPTY in GROUP_FREE --
>> back
>> out Edgar's changed and put in some big comments about exactly
>> why. :-)
>>
>> Comments?
>>
>>
> Note, CT6 (Sun's previous implemention) also passed these tests. Sun
> would like this test passing
> to be maintained until some concrete message is made by the forum.
> That
> being said I would agree
> with Jeff's proposal of backing out the change and putting in
> comments why.
>
> --td
>
>> On Dec 6, 2007, at 11:01 AM, Jeff Squyres wrote:
>>
>>
>>> So the changes that we debated and had Edgar put in *do* break some
>>> intel tests. Doh! :-(
>>>
>>> MPI_Group_compare_f
>>> MPI_Group_intersection2_c
>>> MPI_Group_intersection2_f
>>>
>>> It looks like these tests are specifically calling MPI_GROUP_FREE on
>>> MPI_GROUP_EMPTY.
>>>
>>> I note that there is code in the ompi/group/group_*.c code that
>>> specifically calls OBJ_RETAIN on ompi_group_empty when we return
>>> MPI_GROUP_EMPTY. I wonder if this RETAIN was added (and the MPI
>>> param
>>> check removed) in reaction to the intel tests...?
>>>
>>> Can someone cite again where we thought the spec said that we should
>>> not free GROUP_EMPTY? Was is just on the argument that it's a
>>> predefined handle and therefore should never be freed?
>>>
>>> I cannot find any specific text in 1.2 or the errata stating that
>>> it's
>>> bad to free GROUP_EMPTY. I agree that this is somewhat counter to
>>> the
>>> rest of the MPI philosophy of not freeing predefined handles,
>>> though.
>>>
>>> --
>>> Jeff Squyres
>>> Cisco Systems
>>> _______________________________________________
>>> devel mailing list
>>> devel_at_[hidden]
>>> http://www.open-mpi.org/mailman/listinfo.cgi/devel
>>>
>>
>>
>>
>
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-- 
Jeff Squyres
Cisco Systems