hi edgar, thanks for the tips, I'm gonna try this option as well. the segmentation fault i'm observing always happened during a collective communication indeed... does it basically switch all collective communication to basic mode, right ?
sorry for my ignorance, but what's a NCA ? thanks, éloi On Thursday 15 July 2010 16:20:54 Edgar Gabriel wrote: > you could try first to use the algorithms in the basic module, e.g. > > mpirun -np x --mca coll basic ./mytest > > and see whether this makes a difference. I used to observe sometimes a > (similar ?) problem in the openib btl triggered from the tuned > collective component, in cases where the ofed libraries were installed > but no NCA was found on a node. It used to work however with the basic > component. > > Thanks > Edgar > > On 7/15/2010 3:08 AM, Eloi Gaudry wrote: > > hi Rolf, > > > > unfortunately, i couldn't get rid of that annoying segmentation fault > > when selecting another bcast algorithm. i'm now going to replace > > MPI_Bcast with a naive implementation (using MPI_Send and MPI_Recv) and > > see if that helps. > > > > regards, > > éloi > > > > On Wednesday 14 July 2010 10:59:53 Eloi Gaudry wrote: > >> 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\/ > >>>>>> x 86 _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.d > >>>>>> a t' '--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 > >>>> us...@open-mpi.org > >>>> 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
