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 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
             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  shortened  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
   identification 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 nnode,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)





Opportunity


Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.

Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.





Free Software


Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.


Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.





Free Books


The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.


Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.





Education


Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.


Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.