Open MPI logo

Open MPI User's Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Open MPI User's mailing list

Subject: Re: [OMPI users] [openib] segfault when using openib btl
From: Eloi Gaudry (eg_at_[hidden])
Date: 2010-07-14 04:59:53


Hi Rolf,

thanks for your input. You're right, I miss the coll_tuned_use_dynamic_rules option.

I'll check if I the segmentation fault disappears when using the basic bcast linear algorithm using the proper command line you provided.

Regards,
Eloi

On Tuesday 13 July 2010 20:39:59 Rolf vandeVaart wrote:
> Hi Eloi:
> To select the different bcast algorithms, you need to add an extra mca
> parameter that tells the library to use dynamic selection.
> --mca coll_tuned_use_dynamic_rules 1
>
> One way to make sure you are typing this in correctly is to use it with
> ompi_info. Do the following:
> ompi_info -mca coll_tuned_use_dynamic_rules 1 --param coll
>
> You should see lots of output with all the different algorithms that can
> be selected for the various collectives.
> Therefore, you need this:
>
> --mca coll_tuned_use_dynamic_rules 1 --mca coll_tuned_bcast_algorithm 1
>
> Rolf
>
> On 07/13/10 11:28, Eloi Gaudry wrote:
> > Hi,
> >
> > I've found that "--mca coll_tuned_bcast_algorithm 1" allowed to switch to
> > the basic linear algorithm. Anyway whatever the algorithm used, the
> > segmentation fault remains.
> >
> > Does anyone could give some advice on ways to diagnose the issue I'm
> > facing ?
> >
> > Regards,
> > Eloi
> >
> > On Monday 12 July 2010 10:53:58 Eloi Gaudry wrote:
> >> Hi,
> >>
> >> I'm focusing on the MPI_Bcast routine that seems to randomly segfault
> >> when using the openib btl. I'd like to know if there is any way to make
> >> OpenMPI switch to a different algorithm than the default one being
> >> selected for MPI_Bcast.
> >>
> >> Thanks for your help,
> >> Eloi
> >>
> >> On Friday 02 July 2010 11:06:52 Eloi Gaudry wrote:
> >>> Hi,
> >>>
> >>> I'm observing a random segmentation fault during an internode parallel
> >>> computation involving the openib btl and OpenMPI-1.4.2 (the same issue
> >>> can be observed with OpenMPI-1.3.3).
> >>>
> >>> mpirun (Open MPI) 1.4.2
> >>> Report bugs to http://www.open-mpi.org/community/help/
> >>> [pbn08:02624] *** Process received signal ***
> >>> [pbn08:02624] Signal: Segmentation fault (11)
> >>> [pbn08:02624] Signal code: Address not mapped (1)
> >>> [pbn08:02624] Failing at address: (nil)
> >>> [pbn08:02624] [ 0] /lib64/libpthread.so.0 [0x349540e4c0]
> >>> [pbn08:02624] *** End of error message ***
> >>> sh: line 1: 2624 Segmentation fault
> >>>
> >>> \/share\/hpc3\/actran_suite\/Actran_11\.0\.rc2\.41872\/RedHatEL\-5\/x86
> >>> _6 4\ /bin\/actranpy_mp
> >>> '--apl=/share/hpc3/actran_suite/Actran_11.0.rc2.41872/RedHatEL-5/x86_64
> >>> /A c tran_11.0.rc2.41872'
> >>> '--inputfile=/work/st25652/LSF_130073_0_47696_0/Case1_3Dreal_m4_n2.dat'
> >>> '--scratch=/scratch/st25652/LSF_130073_0_47696_0/scratch' '--mem=3200'
> >>> '--threads=1' '--errorlevel=FATAL' '--t_max=0.1' '--parallel=domain'
> >>>
> >>> If I choose not to use the openib btl (by using --mca btl self,sm,tcp
> >>> on the command line, for instance), I don't encounter any problem and
> >>> the parallel computation runs flawlessly.
> >>>
> >>> I would like to get some help to be able:
> >>> - to diagnose the issue I'm facing with the openib btl
> >>> - understand why this issue is observed only when using the openib btl
> >>> and not when using self,sm,tcp
> >>>
> >>> Any help would be very much appreciated.
> >>>
> >>> The outputs of ompi_info and the configure scripts of OpenMPI are
> >>> enclosed to this email, and some information on the infiniband drivers
> >>> as well.
> >>>
> >>> Here is the command line used when launching a parallel computation
> >>>
> >>> using infiniband:
> >>> path_to_openmpi/bin/mpirun -np $NPROCESS --hostfile host.list --mca
> >>>
> >>> btl openib,sm,self,tcp --display-map --verbose --version --mca
> >>> mpi_warn_on_fork 0 --mca btl_openib_want_fork_support 0 [...]
> >>>
> >>> and the command line used if not using infiniband:
> >>> path_to_openmpi/bin/mpirun -np $NPROCESS --hostfile host.list --mca
> >>>
> >>> btl self,sm,tcp --display-map --verbose --version --mca
> >>> mpi_warn_on_fork 0 --mca btl_openib_want_fork_support 0 [...]
> >>>
> >>> Thanks,
> >>> Eloi
> >
> > _______________________________________________
> > users mailing list
> > users_at_[hidden]
> > http://www.open-mpi.org/mailman/listinfo.cgi/users

-- 
Eloi Gaudry
Free Field Technologies
Company Website: http://www.fft.be
Company Phone:   +32 10 487 959