Hi Rob, As you pointed out in April that there are many cases that could arouse ADIOI_Set_lock error. My code writes to a file at a location specified by a shared file pointer (it is a blocking and collective call): MPI_File_write_ordered(contactFile, const_cast<char*> (inf.str().c_str()), length, MPI_CHAR, &status);
That is why disabling data-sieving does not work for me, even if I tested it with latest openmpi-1.8.2 and gcc-4.9.1. Can I ask a question? Except that Lustre is mounted with "flock" option, is there other workaround to avoid this ADIOI_Set_lock error in MPI-2 parallel IO? Thanks, Beichuan -----Original Message----- From: users [mailto:users-boun...@open-mpi.org] On Behalf Of Rob Latham Sent: Monday, April 14, 2014 14:24 To: Open MPI Users Subject: Re: [OMPI users] File locking in ADIO, OpenMPI 1.6.4 On 04/08/2014 05:49 PM, Daniel Milroy wrote: > Hello, > > The file system in question is indeed Lustre, and mounting with flock > isn't possible in our environment. I recommended the following > changes to the users' code: Hi. I'm the ROMIO guy, though I do rely on the community to help me keep the lustre driver up to snuff. > MPI_Info_set(info, "collective_buffering", "true"); MPI_Info_set(info, > "romio_lustre_ds_in_coll", "disable"); MPI_Info_set(info, > "romio_ds_read", "disable"); MPI_Info_set(info, "romio_ds_write", > "disable"); > > Which results in the same error as before. Are there any other MPI > options I can set? I'd like to hear more about the workload generating these lock messages, but I can tell you the situations in which ADIOI_SetLock gets called: - everywhere in NFS. If you have a Lustre file system exported to some clients as NFS, you'll get NFS (er, that might not be true unless you pick up a recent patch) - when writing a non-contiguous region in file, unless you disable data sieving, as you did above. - note: you don't need to disable data sieving for reads, though you might want to if the data sieving algorithm is wasting a lot of data. - if atomic mode was set on the file (i.e. you called MPI_File_set_atomicity) - if you use any of the shared file pointer operations - if you use any of the ordered mode collective operations you've turned off data sieving writes, which is what I would have first guessed would trigger this lock message. So I guess you are hitting one of the other cases. ==rob -- Rob Latham Mathematics and Computer Science Division Argonne National Lab, IL USA _______________________________________________ users mailing list us...@open-mpi.org http://www.open-mpi.org/mailman/listinfo.cgi/users
