MPITASK (1)
Monitor MPI processes under LAM.
SYNTAX
0
mpitask [-cdh] [-gps] [<nodes>] [<processes>]
1
OPTIONS
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.
n .ta 21 35 46 53 60 68
t .ta 1.25i 2.5i 3.75i 4.5i 5.25i 6i
0
% 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>
<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.
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 n<node>,i<index>.
If the -gps option is given then the GPS is substituted for the global rank (G).
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).
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
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