MPI_FILE_SET_INFO(3)

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version 5.0.10 · 7 versions
, in ubuntu stonking

💖 MPI_FILE_SET_INFO 💖

okay bestie, gather round, because today we're talking about an Open MPI classic: the MPI_FILE_SET_INFO(3) page. yes this is a real man page, yes it lives in section 3, and yes it's about to be your new obsession. it's giving "collective hint glow-up" and honestly? slay. 🎀

✨ NAME ✨

MPI_File_set_info — Sets new values for hints (collective). 🦋

🌸 SYNTAX 🌸

no cap, there's a syntax for basically every language you might be living in:

C Syntax

#include <mpi.h>

int MPI_File_set_info(MPI_File fh, MPI_Info info)

Fortran Syntax

USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_FILE_SET_INFO(FH, INFO, IERROR)
     INTEGER FH, INFO, IERROR

Fortran 2008 Syntax

USE mpi_f08
MPI_File_set_info(fh, info, ierror)
     TYPE(MPI_File), INTENT(IN) :: fh
     TYPE(MPI_Info), INTENT(IN) :: info
     INTEGER, OPTIONAL, INTENT(OUT) :: ierror

🫶 INPUT/OUTPUT PARAMETER 🫶

  • fh — File handle (handle). it's a handle. that's the whole vibe.

🍓 INPUT PARAMETER 🍓

  • info — Info object (handle). your little bundle of hints, holding all the gossip about how you want things done.

💜 OUTPUT PARAMETER 💜

  • ierror — Fortran only: Error status (integer).

👑 DESCRIPTION 👑

okay so MPI_File_set_info is a collective routine that sets new values for the hints of the file associated with fh. these hints get set for each file, and you do it using the MPI_File_open, MPI_File_delete, MPI_File_set_view, and MPI_File_set_info routines. 💅

the opaque info object — which is the whole mechanism letting you hand over hints so your code can get optimized — may be different on each process, no cap. BUT. and this is the important part, bestie: some info entries are required to be the same on all processes. in those cases they must appear with the same value in each process's info object. periodt. 🌈

peep the HINTS section below for the list of hints you can set. 🔥

🧚 HINTS 🧚

these are the hints you can use as values for the info argument. iconic lineup honestly.

✨ SETTABLE HINTS ✨

  • shared_file_timeout — Amount of time (in seconds) to wait for access to the shared file pointer before exiting with MPI_ERR_TIMEDOUT.
  • rwlock_timeout — Amount of time (in seconds) to wait for obtaining a read or write lock on a contiguous chunk of a UNIX file before exiting with MPI_ERR_TIMEDOUT.
  • noncoll_read_bufsize — Maximum size of the buffer used by MPI I/O to satisfy read requests in the noncollective data-access routines.
Note: 🚨 A buffer size smaller than the distance (in bytes) in a UNIX file between the first byte and the last byte of the access request causes MPI I/O to iterate and perform multiple UNIX read() or write() calls. If the request includes multiple noncontiguous chunks of data, and the buffer size is greater than the size of those chunks, then the UNIX read() or write() (made at the MPI I/O level) will access data not requested by this process in order to reduce the total number of write() calls made. If this is not desirable behavior, you should reduce this buffer size to equal the size of the contiguous chunks within the aggregate request.
  • noncoll_write_bufsize — Maximum size of the buffer used by MPI I/O to satisfy write requests in the noncollective data-access routines.

See the above note in noncoll_read_bufsize. 👀

  • coll_read_bufsize — Maximum size of the buffer used by MPI I/O to satisfy read requests in the collective data-access routines.

See the above note in noncoll_read_bufsize. 👀

  • coll_write_bufsize — Maximum size of the buffer used by MPI I/O to satisfy write requests in the collective data-access routines.

See the above note in noncoll_read_bufsize. 👀

  • mpiio_concurrency — (boolean) controls whether nonblocking I/O routines can bind an extra thread to an LWP.
  • mpiio_coll_contiguous — (boolean) controls whether subsequent collective data accesses will request collectively contiguous regions of the file.

🌙 NON-SETTABLE HINTS 🌙

  • filename — Access this hint to get the name of the file.

💀 ERRORS 💀

almost all MPI routines return an error value, bestie — C routines give it back as the return result of the function, and Fortran routines put it in the last argument.

before that error value comes back, the current MPI error handler associated with the communication object (e.g., communicator, window, file) gets called. if there's no communication object associated with the MPI call, then the call is considered attached to MPI_COMM_SELF and will call the associated MPI error handler. and when MPI_COMM_SELF is not initialized — i.e., before MPI_Init/MPI_Init_thread, after MPI_Finalize, or when using the Sessions Model exclusively — the error raises the initial error handler. 😭

that initial error handler can be changed by calling MPI_Comm_set_errhandler on MPI_COMM_SELF when you're using the World model, or via the mpi_initial_errhandler CLI argument to mpiexec, or via the info key to MPI_Comm_spawn/MPI_Comm_spawn_multiple. and if no other appropriate error handler has been set, then the MPI_ERRORS_RETURN error handler is called for MPI I/O functions, and the MPI_ERRORS_ABORT error handler is called for all other MPI functions.

Open MPI includes three predefined error handlers you can use, and they are:

  • MPI_ERRORS_ARE_FATAL — Causes the program to abort all connected MPI processes.
  • MPI_ERRORS_ABORT — An error handler that can be invoked on a communicator, window, file, or session. When called on a communicator, it acts as if MPI_Abort was called on that communicator. If called on a window or file, acts as if MPI_Abort was called on a communicator containing the group of processes in the corresponding window or file. If called on a session, aborts only the local process.
  • MPI_ERRORS_RETURN — Returns an error code to the application.

MPI applications can also implement their own error handlers by calling:

  • MPI_Comm_create_errhandler then MPI_Comm_set_errhandler
  • MPI_File_create_errhandler then MPI_File_set_errhandler
  • MPI_Session_create_errhandler then MPI_Session_set_errhandler or at MPI_Session_init
  • MPI_Win_create_errhandler then MPI_Win_set_errhandler
⚠️ Note that MPI does not guarantee that an MPI program can continue past an error. fr fr, that's the real tea.

See the MPI man page for a full list of MPI error codes.

See the Error Handling section of the MPI-3.1 standard for more information. 📚

2003-2026, The Open MPI Community

aaaand that's the whole page, bestie!! 🫶 this was MPI_FILE_SET_INFO(3) from the Open MPI manual, dated Sep 10, 2026, copyright 2003-2026, The Open MPI Community. you ate that. go set some hints. 💖✨

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