MPITASK(1)                                                         LAM COMMANDS                                                         MPITASK(1)

NAME

       mpitask - Monitor MPI processes under LAM.

SYNOPSIS

       mpitask [-cdh] [-gps] [nodes] [processes]

OPTIONS

       -c      Print communicator descriptions.  See "Communicators".

       -d      Print datatype descriptions.  See "Datatypes".

       -gps    Print process information in GPS format.

       -h      Print useful information on this command.

       The -c and -d options are mutually exclusive.

DESCRIPTION

       The  mpitask  command  displays  information on processes which are using MPI.  One line is printed for each reported MPI process.  With no
       processes or nodes explicitly specified on the command line, all MPI processes on all nodes are reported.

       % mpitask

       TASK (G/L)    FUNCTION   PEER|ROOT   TAG   COMM    COUNT   DATATYPE
       0/0 trivial   Ssend      1/1         123   WORLD   64      INT
       1/1 trivial   Recv       0/0         456   WORLD   64      INT

       For each process mpitask normally prints the following information:

       TASK      an identification of the process - If the process is currently communicating, a `/' followed by the  process's  rank  within  the
                 current communicator is also displayed.  The executable name, if available, is also displayed.  See "MPI Process Identification".

       FUNCTION  an abbreviated form of the function name if the process is blocked inside an MPI function - Otherwise one of the following execu-
                 tion states is printed:

                 running   free to run on the underlying OS

                 paused    blocked on lam_kpause(2)

                 stopped   stopped by the LAM signal, LAM_SIGARREST - See doom(1).

                 blocked   blocked in a LAM function - In general this should be a transitory state.  Further information on a LAM process's state
                           can be obtained with state(1).

       PEER|ROOT the source or destination of a point-to-point communication or the root process of certain collective communications, followed by
                 a '/' and the process's rank within the current communicator -

       TAG       the message tag, if any, which was specified as a parameter to the current MPI function

       COMM      the communicator ID, if any, which was specified as a parameter to the current MPI function - Communicators  used  in  collective
                 calls are displayed with a * suffix.  Further information on the communicator may be obtained with the -c option.

       COUNT     the element count, if any, which was specified as a parameter to the current MPI function

       DATATYPE  the  element datatype, if any, which was specified as a parameter to the current MPI function - For intrinsic datatypes, a short-
                 ened version of the datatype name is displayed.  For derived datatypes, a datatype label is displayed.   Further  information  on
                 the datatype may be obtained with the -d option.

   MPI Process Identification
       By  default,  MPI processes are identified by their rank in MPI_COMM_WORLD.  We refer to this rank more concisely as the "global" rank (G).
       The rank within the currently employed communicator is referred to as the "local" rank (L).

       Since processes may be dynamically spawned (see MPIL_Spawn(2)) and since multiple concurrent MPI applications are allowed, it  is  possible
       for  multiple MPI_COMM_WORLD communicators to coexist.  In these situations, the global rank is no longer globally unique and the identifi-
       cation is ambiguous.  Thus, LAM provides an alternate way of identifying MPI processes, the GPS (Global Positioning System).   A  process's
       GPS  consists of the nodeid the process is running on and the process's LAM index on that node.  It is displayed in mpitask as the pair nn-
       ode,iindex.  If the -gps option is given then the GPS is substituted for the global rank (G).

   Communicators
       If the -c option is given then information is no longer displayed in the horizontal format described  above.   Instead  for  each  selected
       process currently using a communicator, the information from the TASK column, described above, is given followed by an expanded description
       of the communicator.  This description includes the size of the communicator group(s) and the global identifiers  of  all  members  of  the
       group(s).

   Datatypes
       If  the  -d  option  is  given then information is no longer displayed in the horizontal format described above.  Instead for each selected
       process currently using a communicator, the information from the TASK column, described above, is given followed  by  the  datatype's  type
       map.

EXAMPLES

       mpitask
           Display the status of all MPI processes on all nodes.

       mpitask -c n0 i9
           Display the communicator (if any) of process index 9 on node 0.

DIAGNOSTICS

       If no MPI processes are found, only the title line is displayed.

BUGS

       Sometimes  processes  may  be  shown as blocked inside a non-blocking MPI function.  This occurs when the process is blocked inside the MPI
       function on some internal LAM event.  Such states are highly transitory.

SEE ALSO

       doom(1), libmpi(3), mpirun(1), mpimsg(1), state(1), MPIL_Comm_id(2), MPIL_Type_id(2)

LAM 7.1.4                                                           July, 2007                                                          MPITASK(1)