mpitask - Monitor MPI processes under LAM.


SYNTAX

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


OPTIONS

       -c      Print  communicator descriptions.  See "Communica­
               tors".

       -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 report­
       ed 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 in­
       formation:

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

       FUNCTION  an abbreviated form of the function name if  the
                 process is blocked inside an MPI function - Oth­
                 erwise one of the following 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_SIGAR­
                           REST - See doom(1).

                 <blocked> blocked in a LAM function - In general
                           this  should  be  a  transitory state.

                           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 communica­
                 tor -

       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  dis­
                 played  with a * suffix.  Further information 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  speci­
                 fied  as a parameter to the current MPI function
                 - For intrinsic datatypes, a  shortened  version
                 of  the datatype name is displayed.  For derived
                 datatypes, a datatype label is displayed.   Fur­
                 ther 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  em­
       ployed  communicator  is  referred  to as the "local" rank
       (L).

       Since  processes   may   be   dynamically   spawned   (see
       MPIL_Spawn(2))  and since multiple concurrent MPI applica­
       tions  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  identification  is  ambiguous.  Thus, LAM provides an
       alternate way of identifying MPI processes, the GPS (Glob­
       al  Positioning  System).  A process's GPS consists of the
       nodeid the process is running on and the process's LAM in­
       dex  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 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.   In­
       stead for each selected process currently using a communi­

       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.  In­
       stead for each selected process currently using a communi­
       cator,  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 dis­
       played.


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)


Man(1) output converted with man2html