MPITASK(1) LAM COMMANDS MPITASK(1)NAMEmpitask - Monitor MPI processes under LAM.
SYNTAXmpitask [-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.
% mpitaskTASK (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
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 commu‐
nicator 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.
EXAMPLESmpitask
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 ALSOdoom(1), libmpi(3), mpirun(1), mpimsg(1), state(1), MPIL_Comm_id(2),
MPIL_Type_id(2)LAM 7.1.2 March, 2006 MPITASK(1)
