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Subject: Re: [OMPI users] Valgrind Warning
From: Gabriele Fatigati (g.fatigati_at_[hidden])
Date: 2008-12-15 09:34:51


PS: i'm using openmpi 1.2.5..

2008/12/15 Gabriele Fatigati <g.fatigati_at_[hidden]>:
> Hi Jeff,
> i recompiled libibverbs and libmthca with valgrind flas, but for
> strage reasons, only warning over MPI_Send are disappears, but
> warnings over MPI_Recv remains!
>
> 2008/12/15 Jeff Squyres <jsquyres_at_[hidden]>:
>> Whoops; that was a reply to the wrong message. :-)
>>
>> You'll need to recompile both libiverbs and libmthca with the valgrind flag,
>> and use the enhanced memchecker support in v1.3.
>>
>> I have not personally verified that all the warnings disappear in this
>> configuration (I was hoping to verify this somewhere during the v1.3
>> series).
>>
>>
>>
>>>
>>> On Dec 15, 2008, at 6:37 AM, Gabriele Fatigati wrote:
>>>
>>>> Hi Jeff,
>>>> i recompiled libmthca with --with-valgrind flag, and modified
>>>> enviroment variables, but warnings doesnt' disappears..
>>>>
>>>> 2008/12/14 Jeff Squyres <jsquyres_at_[hidden]>:
>>>>>
>>>>> On Dec 14, 2008, at 8:21 AM, Gabriele Fatigati wrote:
>>>>>
>>>>>> i have a strage problems with OpenMPI 1.2.5 Intel Compiled when i
>>>>>> debug my code under Valgrind 3.3. In a very simple ping-pong MPI
>>>>>> application, i retrieve strange warnings about MPI Communications,
>>>>>> like MPI_Send,MPI_Recv. Valgrind tells me that there are uninitialized
>>>>>> values in send/recv buffers, but there are initialized, i'm absolutely
>>>>>> sure!
>>>>>>
>>>>>> There warnings are detected when my application runs over Infiniband
>>>>>> net,
>>>>>
>>>>> This is because IB uses memory that does not come from the memory
>>>>> allocator
>>>>> that Valgrind is aware of (e.g., it may be memory that was allocated by
>>>>> the
>>>>> kernel itself). Hence, since Valgrind is unaware of the memory, it
>>>>> thinks
>>>>> that its contents are undefined. As such, it's quite likely that you're
>>>>> seeing false positives.
>>>>>
>>>>> The memchecker support in the upcoming v1.3 series made quite a few
>>>>> advancements in the area of valgrind memory checking, and recent
>>>>> versions of
>>>>> libibverbs allow you to compile in valgrind extensions that tell
>>>>> valgrind
>>>>> "this memory is ok" (which prevents these false positives). I'm pretty
>>>>> sure
>>>>> that the OFED install does not enable these libibverbs valgrind
>>>>> extensions;
>>>>> you will likely need your own installation of libibverbs and your verbs
>>>>> plugin (libmthca for you, I think...?) that explicitly has the valgrind
>>>>> extensions enabled.
>>>>>
>>>>> --
>>>>> Jeff Squyres
>>>>> Cisco Systems
>>>>>
>>>>> _______________________________________________
>>>>> users mailing list
>>>>> users_at_[hidden]
>>>>> http://www.open-mpi.org/mailman/listinfo.cgi/users
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Ing. Gabriele Fatigati
>>>>
>>>> Parallel programmer
>>>>
>>>> CINECA Systems & Tecnologies Department
>>>>
>>>> Supercomputing Group
>>>>
>>>> Via Magnanelli 6/3, Casalecchio di Reno (BO) Italy
>>>>
>>>> www.cineca.it Tel: +39 051 6171722
>>>>
>>>> g.fatigati_at_[hidden]
>>>> _______________________________________________
>>>> users mailing list
>>>> users_at_[hidden]
>>>> http://www.open-mpi.org/mailman/listinfo.cgi/users
>>>
>>>
>>> --
>>> Jeff Squyres
>>> Cisco Systems
>>>
>>> _______________________________________________
>>> users mailing list
>>> users_at_[hidden]
>>> http://www.open-mpi.org/mailman/listinfo.cgi/users
>>
>>
>> --
>> Jeff Squyres
>> Cisco Systems
>>
>> _______________________________________________
>> users mailing list
>> users_at_[hidden]
>> http://www.open-mpi.org/mailman/listinfo.cgi/users
>>
>>
>
>
>
> --
> Ing. Gabriele Fatigati
>
> Parallel programmer
>
> CINECA Systems & Tecnologies Department
>
> Supercomputing Group
>
> Via Magnanelli 6/3, Casalecchio di Reno (BO) Italy
>
> www.cineca.it Tel: +39 051 6171722
>
> g.fatigati_at_[hidden]
>

-- 
Ing. Gabriele Fatigati
Parallel programmer
CINECA Systems & Tecnologies Department
Supercomputing Group
Via Magnanelli 6/3, Casalecchio di Reno (BO) Italy
www.cineca.it                    Tel:   +39 051 6171722
g.fatigati_at_[hidden]