DragonFly On-Line Manual Pages
MPI_Win_lock_all(3) MPI MPI_Win_lock_all(3)
MPI_Win_lock_all - Begin an RMA access epoch at all processes on the
int MPI_Win_lock_all(int assert, MPI_Win win)
Starts an RMA access epoch to all processes in win, with a lock type of
MPI_Lock_shared . During the epoch, the calling process can access the
window memory on all processes in win by using RMA operations. A window
locked with MPI_Win_lock_all must be unlocked with MPI_Win_unlock_all .
This routine is not collective -- the ALL refers to a lock on all
members of the group of the window.
assert - Used to optimize this call; zero may be used as a default.
See notes. (integer)
win - window object (handle)
This call is not collective.
The assert argument is used to indicate special conditions for the
fence that an implementation may use to optimize the MPI_Win_lock_all
operation. The value zero is always correct. Other assertion values
may be or'ed together. Assertions that are valid for MPI_Win_lock_all
- No other process holds, or will attempt to acquire a
conflicting lock, while the caller holds the window lock. This
is useful when mutual exclusion is achieved by other means, but
the coherence operations that may be attached to the lock and
unlock calls are still required.
There may be additional overheads associated with using
MPI_Win_lock and MPI_Win_lock_all concurrently on the same
window. These overheads could be avoided by specifying the
assertion MPI_MODE_NOCHECK when possible
THREAD AND INTERRUPT SAFETY
This routine is thread-safe. This means that this routine may be
safely used by multiple threads without the need for any user-provided
thread locks. However, the routine is not interrupt safe. Typically,
this is due to the use of memory allocation routines such as malloc or
other non-MPICH runtime routines that are themselves not interrupt-
NOTES FOR FORTRAN
All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have
an additional argument ierr at the end of the argument list. ierr is
an integer and has the same meaning as the return value of the routine
in C. In Fortran, MPI routines are subroutines, and are invoked with
the call statement.
All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in
All MPI routines (except MPI_Wtime and MPI_Wtick ) return an error
value; C routines as the value of the function and Fortran routines in
the last argument. Before the value is returned, the current MPI error
handler is called. By default, this error handler aborts the MPI job.
The error handler may be changed with MPI_Comm_set_errhandler (for
communicators), MPI_File_set_errhandler (for files), and
MPI_Win_set_errhandler (for RMA windows). The MPI-1 routine
MPI_Errhandler_set may be used but its use is deprecated. The
predefined error handler MPI_ERRORS_RETURN may be used to cause error
values to be returned. Note that MPI does not guarentee that an MPI
program can continue past an error; however, MPI implementations will
attempt to continue whenever possible.
- No error; MPI routine completed successfully.
- Invalid source or destination rank. Ranks must be between
zero and the size of the communicator minus one; ranks in a
receive ( MPI_Recv , MPI_Irecv , MPI_Sendrecv , etc.) may also
be MPI_ANY_SOURCE .
- Invalid MPI window object
- Other error; use MPI_Error_string to get more information
about this error code.