mpitask



MPITASK(1)                       LAM COMMANDS                       MPITASK(1)




NAME

       mpitask - Monitor MPI processes under LAM.


SYNTAX

       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  pro-
       cesses  or nodes explicitly specified on the command line, all MPI pro-
       cesses 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 current-
                 ly 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 follow-
                 ing execution 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 parame-
                 ter  to the current MPI function - Communicators used in col-
                 lective calls are displayed with a * suffix.  Further  infor-
                 mation  on  the  communicator may be obtained with the -c op-
                 tion.

       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 param-
                 eter to the current MPI function - For intrinsic datatypes, a
                 shortened version of the datatype name is displayed.  For de-
                 rived datatypes, a datatype label is displayed.  Further  in-
                 formation 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  re-
       ferred 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 situa-
       tions, the global rank is no longer globally unique and the identifica-
       tion  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
       n<node>,i<index>.   If the -gps option is given then the GPS is substi-
       tuted 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 pro-
       cess currently using a communicator, the information from the TASK col-
       umn,  described  above, is given followed by an expanded description of
       the communicator.  This description includes the size of the communica-
       tor 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 pro-
       cess currently using a communicator, the information from the TASK col-
       umn, 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 func-
       tion 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 7.1.1                       September, 2004                     MPITASK(1)

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