mpitask - Monitor MPI processes under LAM.
mpitask
[-cdh] [-gps] [nodes] [processes]
- -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.
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.
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).
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.
- 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.
If no MPI processes are found, only the title line is displayed.
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.
doom(1),
libmpi(3),
mpirun(1),
mpimsg(1),
state(1),
MPIL_Comm_id(2),
MPIL_Type_id(2)