Use the executable program location as the current working directory
for created processes. The current working directory of the created
processes will be set before the user's program is invoked.
-f
Do not configure standard I/O file descriptors - use defaults.
-h
Print useful information on this command.
-np <#>
Run this many copies of the program on the given nodes. This option
indicates that the specified file is an executable program and not an
application schema. If no nodes are specified, all LAM nodes are
considered for scheduling; LAM will schedule the programs in a
round-robin fashion, "wrapping around" (and scheduling multiple copies
on a single node) if necessary.
-nw
Do not wait for all processes to complete before exiting
lamexec.
This option is mutually exclusive with
-w.
-pty
Enable pseudo-tty support. Among other things, this enabled
line-buffered output (which is probably what you want). The only
reason that this feature is not enabled by default is because it is so
new and has not been extensively tested yet.
-s <node>
Load the program from this node. This option is not valid on the
command line if an application schema is specified.
-v
Be verbose; report on important steps as they are done.
-w
Wait for all applications to exit before
lamexec
exits.
-x
Export the specified environment variables to the remote nodes before
executing the program. Existing environment variables can be
specified (see the Examples section, below), or new variable names
specified with corresponding values. The parser for the
-x
option is not very sophisticated; it does not even understand quoted
values. Users are advised to set variables in the environment, and
then use
-x
to export (not define) them.
-- <args>
Pass these runtime arguments to every new process. This must always
be the last argument to
lamexec.
This option is not valid on the command line if an application schema
is specified.
DESCRIPTION
lamexec
is essentially a clone of the
mpirun(1),
but is intended for non-MPI programs.
One invocation of
lamexec
starts a non-MPI application running under LAM. To start the same
program on all LAM nodes, the application can be specified on the
lamexec
command line. To start multiple applications on the LAM nodes, an
application schema is required in a separate file. See appschema(5)
for a description of the application schema syntax, but it essentially
contains multiple
lamexec
command lines, less the command name itself. The ability to specify
different options for different instantiations of a program is another
reason to use an application schema.
Application Schema or Executable Program?
To distinguish the two different forms,
lamexec
looks on the command line for <nodes> or the -c option. If
neither is specified, then the file named on the command line is
assumed to be an application schema. If either one or both are
specified, then the file is assumed to be an executable program. If
<nodes> and -c both are specified, then copies of the program
are started on the specified nodes according to an internal LAM
scheduling policy. Specifying just one node effectively forces LAM to
run all copies of the program in one place. If -c is given, but
not <nodes>, then all LAM nodes are used. If <nodes> is given, but
not -c, then one copy of the program is run on each node.
Program Transfer
By default, LAM searches for executable programs on the target node
where a particular instantiation will run. If the file system is not
shared, the target nodes are homogeneous, and the program is
frequently recompiled, it can be convenient to have LAM transfer the
program from a source node (usually the local node) to each target
node. The -s option specifies this behavior and identifies the
single source node.
Locating Files
LAM looks for an executable program by searching the directories in
the user's PATH environment variable as defined on the source node(s).
This behavior is consistent with logging into the source node and
executing the program from the shell. On remote nodes, the "." path
is the home directory.
LAM looks for an application schema in three directories: the local
directory, the value of the LAMAPPLDIR environment variable, and
LAMHOME/boot, where LAMHOME is the LAM installation directory.
Standard I/O
LAM directs UNIX standard input to /dev/null on all remote nodes. On
the local node that invoked
lamexec,
standard input is inherited from
lamexec.
The default is what used to be the -w option to prevent conflicting
access to the terminal.
LAM directs UNIX standard output and error to the LAM daemon on all
remote nodes. LAM ships all captured output/error to the node that
invoked
lamexec
and prints it on the standard output/error of
lamexec.
Local processes inherit the standard output/error of
lamexec
and transfer to it directly.
Thus it is possible to redirect standard I/O for LAM applications by
using the typical shell redirection procedure on
lamexec.
% lamexec N my_app < my_input > my_output
The
-f
option avoids all the setup required to support standard I/O described
above. Remote processes are completely directed to /dev/null and
local processes inherit file descriptors from lamboot(1).
Pseudo-tty support
The
-pty
option enabled pseudo-tty support for process output. This allows,
among other things, for line buffered output from remote nodes (which
is probably what you want).
This option is not currently the default for
lamexec
because it has not been thoroughly tested on a variety of different
Unixes. Users are encouraged to use
-pty
and report any problems back to the LAM Team.
Current Working Directory
The current working directory for new processes created on the local
node is inherited from
lamexec.
The current working directory for new processes created on remote
nodes is the remote user's home directory. This default behavior is
overridden by the
-D
option.
The
-D
option will change the current working directory of new processes to
the directory where the executable resides before the new user's
program is invoked.
An alternative to the
-D
option is the
-wd
option.
-wd
allows the user to specify an arbitrary current working directory
(vs. the location of the executable). Note that the
-wd
option can be used in application schema files (see appschema(5)) as
well.
Process Environment
Processes in the application inherit their environment from the LAM
daemon upon the node on which they are running. The environment of a
LAM daemon is fixed upon booting of the LAM with lamboot(1) and is
inherited from the user's shell. On the origin node this will be the
shell from which lamboot(1) was invoked and on remote nodes this will
be the shell started by rsh(1). When running dynamically linked
applications which require the LD_LIBRARY_PATH environment variable to
be set, care must be taken to ensure that it is correctly set when
booting the LAM.
Exported Environment Variables
The
-x
option to
lamexec
can be used to export specific environment variables to the new
processes. While the syntax of the
-x
option allows the definition of new variables, note that the parser
for this option is currently not very sophisticated - it does not even
understand quoted values. Users are advised to set variables in the
environment and use
-x
to export them; not to define them.
EXAMPLES
lamexec N prog1
Load and execute prog1 on all nodes.
Search for the executable file on each node.
lamexec -c 8 prog1
Run 8 copies of prog1 wherever LAM wants to run them.
lamexec n8-10 -v -nw -s n3 prog1 -- -q
Load and execute prog1 on nodes 8, 9, and 10. Search for prog1 on
node 3 and transfer it to the three target nodes. Report as each
process is created. Give "-q" as a command line to each new process.
Do not wait for the processes to complete before exiting
lamexec.
lamexec -v myapp
Parse the application schema, myapp, and start all processes specified
in it. Report as each process is created.
lamexec N N -pty -wd /workstuff/output -x DISPLAY run_app.csh
Run the application "run_app.csh" (assumedly a C shell script) twice
on each node in the system (ideal for 2-way SMPs). Also enable
pseudo-tty support, change directory to /workstuff/output, and export
the DISPLAY variable to the new processes (perhaps the shell script
will invoke an X application such as xv to display output).
lamexec -np 5 -D `pwd`/my_application
A common usage of
lamexec
in environments where a filesystem is shared between all nodes in the
multicomputer, using the shell-escaped "pwd" command specifies the
full name of the executable to run. This prevents the need for
putting the directory in the path; the remote notes will have an
absolute filename to execute (and change directory to it upon
invocation).
DIAGNOSTICS
lamexec: Exec format error
A non-ASCII character was detected in the application schema.
This is usually a command line usage error where
lamexec
is expecting an application schema and an executable file was given.
lamexec: syntax error in application schema, line XXX
The application schema cannot be parsed because of a usage or syntax error
on the given line in the file.
<filename>: No such file or directory
This error can occur in two cases. Either the named file cannot be
located or it has been found but the user does not have sufficient
permissions to execute the program or read the application schema.
