mpich_quiet.tex

刚才是说明 现在是安装程序在 LINUX环境下进行编程的MPICH安装文件

\startmanpage
\mantitle{MPICH{\tt \char`\_}Quiet}{tex}{10/7/2002}
\manname{MPICH{\tt \char`\_}Quiet}
--- Call a user-specified function when a communicator is quiet 
\subhead{Synopsis}
\startvb\begin{verbatim}
int MPICH_Quiet( MPID_Comm *comm, 
                 int (*checkpointfunction)(MPI_Comm *, void *), 
                 void *extra_data )

\end{verbatim}
\endvb

\subhead{Input Parameters}
\startarg{comm }{Pointer to a communicator
}
\startarg{checkpointfunction }{User function to call.  The parameters are {\tt comm
}and {\tt extra{\tt \char`\_}data}.  
}
\startarg{extra{\tt \char`\_}data }{A pointer that is passed to {\tt checkpointfunction}.
}
\par
\subhead{Return value}
The function {\tt checkpointfunction} returns {\tt 0} on success and a negative
integer on failure.  This value is returned by {\tt MPICH{\tt \char`\_}Quiet}.  If
{\tt MPICH{\tt \char`\_}Quiet} fails for some other reason, it returns an MPI error code
(a positive value).
\par
\subhead{Notes}
This routine can be used to provide for checkpointing operations where
the user and the MPI implementation together guarantee that no communication
is taking place, even by the low levels of the implementation, on the
specified communicator while {\tt checkpointfunction} is running.  In addition,
all communication is completed if possible.  That is, if any {\tt MPI{\tt \char`\_}Request
}(made in the specified communicator) given to {\tt MPI{\tt \char`\_}Test} would cause
{\tt MPI{\tt \char`\_}Test} to return {\tt true} for the {\tt flag} value (i.e., the communication
described by the request was completed), the communication must be completed
before {\tt checkpointfunction} is called.
\par
This is a collective call with semantics similiar to {\tt MPI{\tt \char`\_}Barrier}, with
the change that after all processes have entered {\tt MPICH{\tt \char`\_}Quiet}, the
user-specified function {\tt checkpointfunction} is called (collectively), and
once that routine returns, a process can leave {\tt MPICH{\tt \char`\_}Quiet}.
\par
\subhead{Question}
An alternative to this is a variation on the two-phase collective routines,
using a begin and end pair to bracket the quiet period.  This allows the
user to call almost any function between the begin and end.  One advantage
to this approach is that it does not require that the user create a
structure for the {\tt extra{\tt \char`\_}data}, and it can make it easier to handle
problems encountered during {\tt checkpointfunction} (e.g., out of disk space
while writing the checkpoint).  This could be handled in a way similar to
attribute copying in {\tt MPI{\tt \char`\_}Comm{\tt \char`\_}dup}, but this is more convenient than the
MPI error handling.
\par
\subhead{Module}
Extension
\endmanpage