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From: Graham E Fagg (fagg_at_[hidden])
Date: 2006-09-11 19:31:10


Hi Christian, do you have the ticket #, I just looked and didn't see it
listed...

G.

On Tue, 12 Sep 2006, Christian Siebert wrote:

> Hi,
>
> I stumbled across a serious bug in the tuned component of Open MPI,
> which crashes for example the well-known HPL benchmark in conjunction
> with the "native MPI_Bcast() patch" [1].
>
> The problem is within the function ompi_coll_tuned_bcast_intra_chain(),
> which does mainly the following:
>
> ompi_ddt_type_size( datatype, &typelng );
> segcount = segsize / typelng;
> num_segments = count / segcount;
>
> Whenever you have a constructed type with a size larger than 'segsize'
> (16384), you'll get a 'seqcount' of zero and finally a division by zero.
>
> Happy fixing!
>
> Christian
>
> [1] http://www-user.tu-chemnitz.de/~chsi/hpl/
>
>
> _______________________________________________
> devel mailing list
> devel_at_[hidden]
> http://www.open-mpi.org/mailman/listinfo.cgi/devel
>

Thanks,
         Graham.
----------------------------------------------------------------------
Dr Graham E. Fagg | Distributed, Parallel and Meta-Computing
Innovative Computing Lab. PVM3.4, HARNESS, FT-MPI, SNIPE & Open MPI
Computer Science Dept | Suite 203, 1122 Volunteer Blvd,
University of Tennessee | Knoxville, Tennessee, USA. TN 37996-3450
Email: fagg_at_[hidden] | Phone:+1(865)974-5790 | Fax:+1(865)974-8296
Broken complex systems are always derived from working simple systems
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