Provided by: openmpi-bin_1.10.2-8ubuntu1_amd64 
NAME
orte-submit, ompi-submit - Execute serial and parallel jobs in Open MPI using a DVM.
Note: ompi-submit and orte-submit are synonyms for each other. Using either of the names
will produce the same behavior.
SYNOPSIS
Single Process Multiple Data (SPMD) Model:
ompi-submit [ options ] <program> [ <args> ]
Multiple Instruction Multiple Data (MIMD) Model:
ompi-submit [ global_options ]
[ local_options1 ] <program1> [ <args1> ] :
[ local_options2 ] <program2> [ <args2> ] :
... :
[ local_optionsN ] <programN> [ <argsN> ]
Note that in both models, invoking ompi-submit via an absolute path name is equivalent to
specifying the --prefix option with a <dir> value equivalent to the directory where ompi-
submit resides, minus its last subdirectory. For example:
% /usr/local/bin/ompi-submit ...
is equivalent to
% ompi-submit --prefix /usr/local
QUICK SUMMARY
Use of orte-submit requires that you first start the Distributed Virtual Machine (DVM)
using orte-dvm.
If you are simply looking for how to run an MPI application, you probably want to use a
command line of the following form:
% ompi-submit [ -np X ] [ --hostfile <filename> ] <program>
This will run X copies of <program> in your current run-time environment (if running under
a supported resource manager, Open MPI's ompi-submit will usually automatically use the
corresponding resource manager process starter, as opposed to, for example, rsh or ssh,
which require the use of a hostfile, or will default to running all X copies on the
localhost), scheduling (by default) in a round-robin fashion by CPU slot. See the rest of
this page for more details.
Please note that ompi-submit automatically binds processes as of the start of the v1.8
series. Two binding patterns are used in the absence of any further directives:
Bind to core: when the number of processes is <= 2
Bind to socket: when the number of processes is > 2
If your application uses threads, then you probably want to ensure that you are either not
bound at all (by specifying --bind-to none), or bound to multiple cores using an
appropriate binding level or specific number of processing elements per application
process.
OPTIONS
ompi-submit will send the name of the directory where it was invoked on the local node to
each of the remote nodes, and attempt to change to that directory. See the "Current
Working Directory" section below for further details.
<program> The program executable. This is identified as the first non-recognized argument
to ompi-submit.
<args> Pass these run-time arguments to every new process. These must always be the
last arguments to ompi-submit. If an app context file is used, <args> will be
ignored.
-h, --help
Display help for this command
-q, --quiet
Suppress informative messages from orte-submit during application execution.
-v, --verbose
Be verbose
-V, --version
Print version number. If no other arguments are given, this will also cause
orte-submit to exit.
Use one of the following options to specify which hosts (nodes) of the DVM to run on.
Specifying hosts outside the DVM will result in an error.
-H, -host, --host <host1,host2,...,hostN>
List of hosts on which to invoke processes.
-hostfile, --hostfile <hostfile>
Provide a hostfile to use.
-machinefile, --machinefile <machinefile>
Synonym for -hostfile.
The following options specify the number of processes to launch. Note that none of the
options imply a particular binding policy - e.g., requesting N processes for each socket
does not imply that the processes will be bound to the socket.
-c, -n, --n, -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 context. If no
value is provided for the number of copies to execute (i.e., neither the "-np" nor
its synonyms are provided on the command line), Open MPI will automatically execute
a copy of the program on each process slot (see below for description of a "process
slot"). This feature, however, can only be used in the SPMD model and will return
an error (without beginning execution of the application) otherwise.
—map-by ppr:N:<object>
Launch N times the number of objects of the specified type on each node.
-npersocket, --npersocket <#persocket>
On each node, launch this many processes times the number of processor sockets on
the node. The -npersocket option also turns on the -bind-to-socket option.
(deprecated in favor of --map-by ppr:n:socket)
-npernode, --npernode <#pernode>
On each node, launch this many processes. (deprecated in favor of --map-by
ppr:n:node)
-pernode, --pernode
On each node, launch one process -- equivalent to -npernode 1. (deprecated in
favor of --map-by ppr:1:node)
To map processes:
--map-by <foo>
Map to the specified object, defaults to socket. Supported options include slot,
hwthread, core, L1cache, L2cache, L3cache, socket, numa, board, node, sequential,
distance, and ppr. Any object can include modifiers by adding a : and any
combination of PE=n (bind n processing elements to each proc), SPAN (load balance
the processes across the allocation), OVERSUBSCRIBE (allow more processes on a node
than processing elements), and NOOVERSUBSCRIBE. This includes PPR, where the
pattern would be terminated by another colon to separate it from the modifiers.
-bycore, --bycore
Map processes by core (deprecated in favor of --map-by core)
-bysocket, --bysocket
Map processes by socket (deprecated in favor of --map-by socket)
-nolocal, --nolocal
Do not run any copies of the launched application on the same node as orte-submit
is running. This option will override listing the localhost with --host or any
other host-specifying mechanism.
-nooversubscribe, --nooversubscribe
Do not oversubscribe any nodes; error (without starting any processes) if the
requested number of processes would cause oversubscription. This option implicitly
sets "max_slots" equal to the "slots" value for each node.
-bynode, --bynode
Launch processes one per node, cycling by node in a round-robin fashion. This
spreads processes evenly among nodes and assigns MPI_COMM_WORLD ranks in a round-
robin, "by node" manner.
To order processes' ranks in MPI_COMM_WORLD:
--rank-by <foo>
Rank in round-robin fashion according to the specified object, defaults to slot.
Supported options include slot, hwthread, core, L1cache, L2cache, L3cache, socket,
numa, board, and node.
For process binding:
--bind-to <foo>
Bind processes to the specified object, defaults to core. Supported options include
slot, hwthread, core, l1cache, l2cache, l3cache, socket, numa, board, and none.
-cpus-per-proc, --cpus-per-proc <#perproc>
Bind each process to the specified number of cpus. (deprecated in favor of --map-
by <obj>:PE=n)
-cpus-per-rank, --cpus-per-rank <#perrank>
Alias for -cpus-per-proc. (deprecated in favor of --map-by <obj>:PE=n)
-bind-to-core, --bind-to-core
Bind processes to cores (deprecated in favor of --bind-to core)
-bind-to-socket, --bind-to-socket
Bind processes to processor sockets (deprecated in favor of --bind-to socket)
-bind-to-none, --bind-to-none
Do not bind processes (deprecated in favor of --bind-to none)
-report-bindings, --report-bindings
Report any bindings for launched processes.
-slot-list, --slot-list <slots>
List of processor IDs to be used for binding MPI processes. The specified bindings
will be applied to all MPI processes. See explanation below for syntax.
For rankfiles:
-rf, --rankfile <rankfile>
Provide a rankfile file.
To manage standard I/O:
-output-filename, --output-filename <filename>
Redirect the stdout, stderr, and stddiag of all processes to a process-unique
version of the specified filename. Any directories in the filename will
automatically be created. Each output file will consist of filename.id, where the
id will be the processes' rank in MPI_COMM_WORLD, left-filled with zero's for
correct ordering in listings.
-stdin, --stdin <rank>
The MPI_COMM_WORLD rank of the process that is to receive stdin. The default is to
forward stdin to MPI_COMM_WORLD rank 0, but this option can be used to forward
stdin to any process. It is also acceptable to specify none, indicating that no
processes are to receive stdin.
-tag-output, --tag-output
Tag each line of output to stdout, stderr, and stddiag with [jobid,
MCW_rank]<stdxxx> indicating the process jobid and MPI_COMM_WORLD rank of the
process that generated the output, and the channel which generated it.
-timestamp-output, --timestamp-output
Timestamp each line of output to stdout, stderr, and stddiag.
-xml, --xml
Provide all output to stdout, stderr, and stddiag in an xml format.
-xterm, --xterm <ranks>
Display the output from the processes identified by their MPI_COMM_WORLD ranks in
separate xterm windows. The ranks are specified as a comma-separated list of
ranges, with a -1 indicating all. A separate window will be created for each
specified process. Note: xterm will normally terminate the window upon termination
of the process running within it. However, by adding a "!" to the end of the list
of specified ranks, the proper options will be provided to ensure that xterm keeps
the window open after the process terminates, thus allowing you to see the process'
output. Each xterm window will subsequently need to be manually closed. Note: In
some environments, xterm may require that the executable be in the user's path, or
be specified in absolute or relative terms. Thus, it may be necessary to specify a
local executable as "./foo" instead of just "foo". If xterm fails to find the
executable, ompi-submit will hang, but still respond correctly to a ctrl-c. If
this happens, please check that the executable is being specified correctly and try
again.
To manage files and runtime environment:
-path, --path <path>
<path> that will be used when attempting to locate the requested executables. This
is used prior to using the local PATH setting.
--prefix <dir>
Prefix directory that will be used to set the PATH and LD_LIBRARY_PATH on the
remote node before invoking Open MPI or the target process. See the "Remote
Execution" section, below.
--preload-binary
Copy the specified executable(s) to remote machines prior to starting remote
processes. The executables will be copied to the Open MPI session directory and
will be deleted upon completion of the job.
--preload-files <files>
Preload the comma separated list of files to the current working directory of the
remote machines where processes will be launched prior to starting those processes.
--preload-files-dest-dir <path>
The destination directory to be used for preload-files, if other than the current
working directory. By default, the absolute and relative paths provided by
--preload-files are used.
-wd <dir>
Synonym for -wdir.
-wdir <dir>
Change to the directory <dir> before the user's program executes. See the "Current
Working Directory" section for notes on relative paths. Note: If the -wdir option
appears both on the command line and in an application context, the context will
take precedence over the command line. Thus, if the path to the desired wdir is
different on the backend nodes, then it must be specified as an absolute path that
is correct for the backend node.
-x <env>
Export the specified environment variables to the remote nodes before executing the
program. Only one environment variable can be specified per -x option. Existing
environment variables can be specified or new variable names specified with
corresponding values. For example:
% ompi-submit -x DISPLAY -x OFILE=/tmp/out ...
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.
Setting MCA parameters:
-gmca, --gmca <key> <value>
Pass global MCA parameters that are applicable to all contexts. <key> is the
parameter name; <value> is the parameter value.
-mca, --mca <key> <value>
Send arguments to various MCA modules. See the "MCA" section, below.
For debugging:
-debug, --debug
Invoke the user-level debugger indicated by the orte_base_user_debugger MCA
parameter.
-debugger, --debugger
Sequence of debuggers to search for when --debug is used (i.e. a synonym for
orte_base_user_debugger MCA parameter).
-tv, --tv
Launch processes under the TotalView debugger. Deprecated backwards compatibility
flag. Synonym for --debug.
There are also other options:
--allow-run-as-root
Allow ompi-submit to run when executed by the root user (ompi-submit defaults to
aborting when launched as the root user).
-aborted, --aborted <#>
Set the maximum number of aborted processes to display.
--app <appfile>
Provide an appfile, ignoring all other command line options.
-cf, --cartofile <cartofile>
Provide a cartography file.
--hetero
Indicates that multiple app_contexts are being provided that are a mix of 32/64-bit
binaries.
-ompi-server, --ompi-server <uri or file>
Specify the URI of the Open MPI server (or the ompi-submit to be used as the
server) , the name of the file (specified as file:filename) that contains that
info, or the PID (specified as pid:#) of the ompi-submit to be used as
the server. The Open MPI server is used to support multi-application data
exchange via the MPI-2 MPI_Publish_name and MPI_Lookup_name functions.
The following options are useful for developers; they are not generally useful to most
ORTE and/or MPI users:
-d, --debug-devel
Enable debugging of the OmpiRTE (the run-time layer in Open MPI). This is not
generally useful for most users.
There may be other options listed with ompi-submit --help.
Environment Variables
MPIEXEC_TIMEOUT
The maximum number of seconds that ompi-submit (mpiexec) will run. After this many
seconds, ompi-submit will abort the launched job and exit.
DESCRIPTION
One invocation of ompi-submit starts an MPI application running under Open MPI. If the
application is single process multiple data (SPMD), the application can be specified on
the ompi-submit command line.
If the application is multiple instruction multiple data (MIMD), comprising of multiple
programs, the set of programs and argument can be specified in one of two ways: Extended
Command Line Arguments, and Application Context.
An application context describes the MIMD program set including all arguments in a
separate file. This file essentially contains multiple ompi-submit 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 context.
Extended command line arguments allow for the description of the application layout on the
command line using colons (:) to separate the specification of programs and arguments.
Some options are globally set across all specified programs (e.g. --hostfile), while
others are specific to a single program (e.g. -np).
Specifying Host Nodes
Host nodes can be identified on the ompi-submit command line with the -host option or in a
hostfile.
For example,
ompi-submit -H aa,aa,bb ./a.out
launches two processes on node aa and one on bb.
Or, consider the hostfile
% cat myhostfile
aa slots=2
bb slots=2
cc slots=2
Since the DVM was started with orte-dvm, orte-submit will ignore any slots arguments in
the hostfile. Values provided via hostfile to orte-dvm will control the behavior.
ompi-submit -hostfile myhostfile ./a.out
will launch two processes on each of the three nodes.
ompi-submit -hostfile myhostfile -host aa ./a.out
will launch two processes, both on node aa.
ompi-submit -hostfile myhostfile -host dd ./a.out
will find no hosts to run on and abort with an error. That is, the specified host dd
is not in the specified hostfile.
Specifying Number of Processes
As we have just seen, the number of processes to run can be set using the hostfile. Other
mechanisms exist.
The number of processes launched can be specified as a multiple of the number of nodes or
processor sockets available. For example,
ompi-submit -H aa,bb -npersocket 2 ./a.out
launches processes 0-3 on node aa and process 4-7 on node bb, where aa and bb are both
dual-socket nodes. The -npersocket option also turns on the -bind-to-socket option,
which is discussed in a later section.
ompi-submit -H aa,bb -npernode 2 ./a.out
launches processes 0-1 on node aa and processes 2-3 on node bb.
ompi-submit -H aa,bb -npernode 1 ./a.out
launches one process per host node.
ompi-submit -H aa,bb -pernode ./a.out
is the same as -npernode 1.
Another alternative is to specify the number of processes with the -np option. Consider
now the hostfile
% cat myhostfile
aa slots=4
bb slots=4
cc slots=4
Now,
ompi-submit -hostfile myhostfile -np 6 ./a.out
will launch processes 0-3 on node aa and processes 4-5 on node bb. The remaining
slots in the hostfile will not be used since the -np option indicated that only 6
processes should be launched.
Mapping Processes to Nodes: Using Policies
The examples above illustrate the default mapping of process processes to nodes. This
mapping can also be controlled with various ompi-submit options that describe mapping
policies.
Consider the same hostfile as above, again with -np 6:
node aa node bb node cc
ompi-submit 0 1 2 3 4 5
ompi-submit --map-by node 0 3 1 4 2 5
ompi-submit -nolocal 0 1 2 3 4 5
The --map-by node option will load balance the processes across the available nodes,
numbering each process in a round-robin fashion.
The -nolocal option prevents any processes from being mapped onto the local host (in this
case node aa). While ompi-submit typically consumes few system resources, -nolocal can be
helpful for launching very large jobs where ompi-submit may actually need to use
noticeable amounts of memory and/or processing time.
Just as -np can specify fewer processes than there are slots, it can also oversubscribe
the slots. For example, with the same hostfile:
ompi-submit -hostfile myhostfile -np 14 ./a.out
will launch processes 0-3 on node aa, 4-7 on bb, and 8-11 on cc. It will then add the
remaining two processes to whichever nodes it chooses.
One can also specify limits to oversubscription. For example, with the same hostfile:
ompi-submit -hostfile myhostfile -np 14 -nooversubscribe ./a.out
will produce an error since -nooversubscribe prevents oversubscription.
Limits to oversubscription can also be specified in the hostfile itself:
% cat myhostfile
aa slots=4 max_slots=4
bb max_slots=4
cc slots=4
The max_slots field specifies such a limit. When it does, the slots value defaults to the
limit. Now:
ompi-submit -hostfile myhostfile -np 14 ./a.out
causes the first 12 processes to be launched as before, but the remaining two
processes will be forced onto node cc. The other two nodes are protected by the
hostfile against oversubscription by this job.
Using the --nooversubscribe option can be helpful since Open MPI currently does not get
"max_slots" values from the resource manager.
Of course, -np can also be used with the -H or -host option. For example,
ompi-submit -H aa,bb -np 8 ./a.out
launches 8 processes. Since only two hosts are specified, after the first two
processes are mapped, one to aa and one to bb, the remaining processes oversubscribe
the specified hosts.
And here is a MIMD example:
ompi-submit -H aa -np 1 hostname : -H bb,cc -np 2 uptime
will launch process 0 running hostname on node aa and processes 1 and 2 each running
uptime on nodes bb and cc, respectively.
Mapping, Ranking, and Binding: Oh My!
Open MPI employs a three-phase procedure for assigning process locations and ranks:
mapping Assigns a default location to each process
ranking Assigns an MPI_COMM_WORLD rank value to each process
binding Constrains each process to run on specific processors
The mapping step is used to assign a default location to each process based on the mapper
being employed. Mapping by slot, node, and sequentially results in the assignment of the
processes to the node level. In contrast, mapping by object, allows the mapper to assign
the process to an actual object on each node.
Note: the location assigned to the process is independent of where it will be bound - the
assignment is used solely as input to the binding algorithm.
The mapping of process processes to nodes can be defined not just with general policies
but also, if necessary, using arbitrary mappings that cannot be described by a simple
policy. One can use the "sequential mapper," which reads the hostfile line by line,
assigning processes to nodes in whatever order the hostfile specifies. Use the -mca rmaps
seq option. For example, using the same hostfile as before:
ompi-submit -hostfile myhostfile -mca rmaps seq ./a.out
will launch three processes, one on each of nodes aa, bb, and cc, respectively. The slot
counts don't matter; one process is launched per line on whatever node is listed on the
line.
Another way to specify arbitrary mappings is with a rankfile, which gives you detailed
control over process binding as well. Rankfiles are discussed below.
The second phase focuses on the ranking of the process within the job's MPI_COMM_WORLD.
Open MPI separates this from the mapping procedure to allow more flexibility in the
relative placement of MPI processes. This is best illustrated by considering the following
two cases where we used the —map-by ppr:2:socket option:
node aa node bb
rank-by core 0 1 ! 2 3 4 5 ! 6 7
rank-by socket 0 2 ! 1 3 4 6 ! 5 7
rank-by socket:span 0 4 ! 1 5 2 6 ! 3 7
Ranking by core and by slot provide the identical result - a simple progression of
MPI_COMM_WORLD ranks across each node. Ranking by socket does a round-robin ranking within
each node until all processes have been assigned an MCW rank, and then progresses to the
next node. Adding the span modifier to the ranking directive causes the ranking algorithm
to treat the entire allocation as a single entity - thus, the MCW ranks are assigned
across all sockets before circling back around to the beginning.
The binding phase actually binds each process to a given set of processors. This can
improve performance if the operating system is placing processes suboptimally. For
example, it might oversubscribe some multi-core processor sockets, leaving other sockets
idle; this can lead processes to contend unnecessarily for common resources. Or, it
might spread processes out too widely; this can be suboptimal if application performance
is sensitive to interprocess communication costs. Binding can also keep the operating
system from migrating processes excessively, regardless of how optimally those processes
were placed to begin with.
The processors to be used for binding can be identified in terms of topological groupings
- e.g., binding to an l3cache will bind each process to all processors within the scope of
a single L3 cache within their assigned location. Thus, if a process is assigned by the
mapper to a certain socket, then a —bind-to l3cache directive will cause the process to be
bound to the processors that share a single L3 cache within that socket.
To help balance loads, the binding directive uses a round-robin method when binding to
levels lower than used in the mapper. For example, consider the case where a job is mapped
to the socket level, and then bound to core. Each socket will have multiple cores, so if
multiple processes are mapped to a given socket, the binding algorithm will assign each
process located to a socket to a unique core in a round-robin manner.
Alternatively, processes mapped by l2cache and then bound to socket will simply be bound
to all the processors in the socket where they are located. In this manner, users can
exert detailed control over relative MCW rank location and binding.
Finally, --report-bindings can be used to report bindings.
As an example, consider a node with two processor sockets, each comprising four cores. We
run ompi-submit with -np 4 --report-bindings and the following additional options:
% ompi-submit ... --map-by core --bind-to core
[...] ... binding child [...,0] to cpus 0001
[...] ... binding child [...,1] to cpus 0002
[...] ... binding child [...,2] to cpus 0004
[...] ... binding child [...,3] to cpus 0008
% ompi-submit ... --map-by socket --bind-to socket
[...] ... binding child [...,0] to socket 0 cpus 000f
[...] ... binding child [...,1] to socket 1 cpus 00f0
[...] ... binding child [...,2] to socket 0 cpus 000f
[...] ... binding child [...,3] to socket 1 cpus 00f0
% ompi-submit ... --map-by core:PE=2 --bind-to core
[...] ... binding child [...,0] to cpus 0003
[...] ... binding child [...,1] to cpus 000c
[...] ... binding child [...,2] to cpus 0030
[...] ... binding child [...,3] to cpus 00c0
% ompi-submit ... --bind-to none
Here, --report-bindings shows the binding of each process as a mask. In the first case,
the processes bind to successive cores as indicated by the masks 0001, 0002, 0004, and
0008. In the second case, processes bind to all cores on successive sockets as indicated
by the masks 000f and 00f0. The processes cycle through the processor sockets in a round-
robin fashion as many times as are needed. In the third case, the masks show us that 2
cores have been bound per process. In the fourth case, binding is turned off and no
bindings are reported.
Open MPI's support for process binding depends on the underlying operating system.
Therefore, certain process binding options may not be available on every system.
Process binding can also be set with MCA parameters. Their usage is less convenient than
that of ompi-submit options. On the other hand, MCA parameters can be set not only on the
ompi-submit command line, but alternatively in a system or user mca-params.conf file or as
environment variables, as described in the MCA section below. Some examples include:
ompi-submit option MCA parameter key value
--map-by core rmaps_base_mapping_policy core
--map-by socket rmaps_base_mapping_policy socket
--rank-by core rmaps_base_ranking_policy core
--bind-to core hwloc_base_binding_policy core
--bind-to socket hwloc_base_binding_policy socket
--bind-to none hwloc_base_binding_policy none
Rankfiles
Rankfiles are text files that specify detailed information about how individual processes
should be mapped to nodes, and to which processor(s) they should be bound. Each line of a
rankfile specifies the location of one process (for MPI jobs, the process' "rank" refers
to its rank in MPI_COMM_WORLD). The general form of each line in the rankfile is:
rank <N>=<hostname> slot=<slot list>
For example:
$ cat myrankfile
rank 0=aa slot=1:0-2
rank 1=bb slot=0:0,1
rank 2=cc slot=1-2
$ ompi-submit -H aa,bb,cc,dd -rf myrankfile ./a.out
Means that
Rank 0 runs on node aa, bound to logical socket 1, cores 0-2.
Rank 1 runs on node bb, bound to logical socket 0, cores 0 and 1.
Rank 2 runs on node cc, bound to logical cores 1 and 2.
Rankfiles can alternatively be used to specify physical processor locations. In this case,
the syntax is somewhat different. Sockets are no longer recognized, and the slot number
given must be the number of the physical PU as most OS's do not assign a unique physical
identifier to each core in the node. Thus, a proper physical rankfile looks something like
the following:
$ cat myphysicalrankfile
rank 0=aa slot=1
rank 1=bb slot=8
rank 2=cc slot=6
This means that
Rank 0 will run on node aa, bound to the core that contains physical PU 1
Rank 1 will run on node bb, bound to the core that contains physical PU 8
Rank 2 will run on node cc, bound to the core that contains physical PU 6
Rankfiles are treated as logical by default, and the MCA parameter
rmaps_rank_file_physical must be set to 1 to indicate that the rankfile is to be
considered as physical.
The hostnames listed above are "absolute," meaning that actual resolveable hostnames are
specified. However, hostnames can also be specified as "relative," meaning that they are
specified in relation to an externally-specified list of hostnames (e.g., by ompi-submit's
--host argument, a hostfile, or a job scheduler).
The "relative" specification is of the form "+n<X>", where X is an integer specifying the
Xth hostname in the set of all available hostnames, indexed from 0. For example:
$ cat myrankfile
rank 0=+n0 slot=1:0-2
rank 1=+n1 slot=0:0,1
rank 2=+n2 slot=1-2
$ ompi-submit -H aa,bb,cc,dd -rf myrankfile ./a.out
Starting with Open MPI v1.7, all socket/core slot locations are be specified as logical
indexes (the Open MPI v1.6 series used physical indexes). You can use tools such as
HWLOC's "lstopo" to find the logical indexes of socket and cores.
Application Context or Executable Program?
To distinguish the two different forms, ompi-submit looks on the command line for --app
option. If it is specified, then the file named on the command line is assumed to be an
application context. If it is not specified, then the file is assumed to be an executable
program.
Locating Files
If no relative or absolute path is specified for a file, Open MPI will first look for
files by searching the directories specified by the --path option. If there is no --path
option set or if the file is not found at the --path location, then Open MPI will search
the user's PATH environment variable as defined on the source node(s).
If a relative directory is specified, it must be relative to the initial working directory
determined by the specific starter used. For example when using the rsh or ssh starters,
the initial directory is $HOME by default. Other starters may set the initial directory to
the current working directory from the invocation of ompi-submit.
Current Working Directory
The -wdir ompi-submit option (and its synonym, -wd) allows the user to change to an
arbitrary directory before the program is invoked. It can also be used in application
context files to specify working directories on specific nodes and/or for specific
applications.
If the -wdir option appears both in a context file and on the command line, the context
file directory will override the command line value.
If the -wdir option is specified, Open MPI will attempt to change to the specified
directory on all of the remote nodes. If this fails, ompi-submit will abort.
If the -wdir option is not specified, Open MPI will send the directory name where ompi-
submit was invoked to each of the remote nodes. The remote nodes will try to change to
that directory. If they are unable (e.g., if the directory does not exist on that node),
then Open MPI will use the default directory determined by the starter.
All directory changing occurs before the user's program is invoked; it does not wait until
MPI_INIT is called.
Standard I/O
Open MPI directs UNIX standard input to /dev/null on all processes except the
MPI_COMM_WORLD rank 0 process. The MPI_COMM_WORLD rank 0 process inherits standard input
from ompi-submit. Note: The node that invoked ompi-submit need not be the same as the
node where the MPI_COMM_WORLD rank 0 process resides. Open MPI handles the redirection of
ompi-submit's standard input to the rank 0 process.
Open MPI directs UNIX standard output and error from remote nodes to the node that invoked
ompi-submit and prints it on the standard output/error of ompi-submit. Local processes
inherit the standard output/error of ompi-submit and transfer to it directly.
Thus it is possible to redirect standard I/O for Open MPI applications by using the
typical shell redirection procedure on ompi-submit.
% ompi-submit -np 2 my_app < my_input > my_output
Note that in this example only the MPI_COMM_WORLD rank 0 process will receive the stream
from my_input on stdin. The stdin on all the other nodes will be tied to /dev/null.
However, the stdout from all nodes will be collected into the my_output file.
Signal Propagation
When orte-submit receives a SIGTERM and SIGINT, it will attempt to kill the entire job by
sending all processes in the job a SIGTERM, waiting a small number of seconds, then
sending all processes in the job a SIGKILL.
SIGUSR1 and SIGUSR2 signals received by orte-submit are propagated to all processes in the
job.
One can turn on forwarding of SIGSTOP and SIGCONT to the program executed by ompi-submit
by setting the MCA parameter orte_forward_job_control to 1. A SIGTSTOP signal to ompi-
submit will then cause a SIGSTOP signal to be sent to all of the programs started by ompi-
submit and likewise a SIGCONT signal to ompi-submit will cause a SIGCONT sent.
Other signals are not currently propagated by orte-submit.
Process Termination / Signal Handling
During the run of an MPI application, if any process dies abnormally (either exiting
before invoking MPI_FINALIZE, or dying as the result of a signal), ompi-submit will print
out an error message and kill the rest of the MPI application.
User signal handlers should probably avoid trying to cleanup MPI state (Open MPI is
currently not async-signal-safe; see MPI_Init_thread(3) for details about
MPI_THREAD_MULTIPLE and thread safety). For example, if a segmentation fault occurs in
MPI_SEND (perhaps because a bad buffer was passed in) and a user signal handler is
invoked, if this user handler attempts to invoke MPI_FINALIZE, Bad Things could happen
since Open MPI was already "in" MPI when the error occurred. Since ompi-submit will
notice that the process died due to a signal, it is probably not necessary (and safest)
for the user to only clean up non-MPI state.
Process Environment
Processes in the MPI application inherit their environment from the Open RTE daemon upon
the node on which they are running. The environment is typically inherited from the
user's shell. On remote nodes, the exact environment is determined by the boot MCA module
used. The rsh launch module, for example, uses either rsh/ssh to launch the Open RTE
daemon on remote nodes, and typically executes one or more of the user's shell-setup files
before launching the Open RTE daemon. 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 Open MPI.
See the "Remote Execution" section for more details.
Remote Execution
Open MPI requires that the PATH environment variable be set to find executables on remote
nodes (this is typically only necessary in rsh- or ssh-based environments --
batch/scheduled environments typically copy the current environment to the execution of
remote jobs, so if the current environment has PATH and/or LD_LIBRARY_PATH set properly,
the remote nodes will also have it set properly). If Open MPI was compiled with shared
library support, it may also be necessary to have the LD_LIBRARY_PATH environment variable
set on remote nodes as well (especially to find the shared libraries required to run user
MPI applications).
However, it is not always desirable or possible to edit shell startup files to set PATH
and/or LD_LIBRARY_PATH. The --prefix option is provided for some simple configurations
where this is not possible.
The --prefix option takes a single argument: the base directory on the remote node where
Open MPI is installed. Open MPI will use this directory to set the remote PATH and
LD_LIBRARY_PATH before executing any Open MPI or user applications. This allows running
Open MPI jobs without having pre-configured the PATH and LD_LIBRARY_PATH on the remote
nodes.
Open MPI adds the basename of the current node's "bindir" (the directory where Open MPI's
executables are installed) to the prefix and uses that to set the PATH on the remote node.
Similarly, Open MPI adds the basename of the current node's "libdir" (the directory where
Open MPI's libraries are installed) to the prefix and uses that to set the LD_LIBRARY_PATH
on the remote node. For example:
Local bindir: /local/node/directory/bin
Local libdir: /local/node/directory/lib64
If the following command line is used:
% ompi-submit --prefix /remote/node/directory
Open MPI will add "/remote/node/directory/bin" to the PATH and
"/remote/node/directory/lib64" to the D_LIBRARY_PATH on the remote node before attempting
to execute anything.
The --prefix option is not sufficient if the installation paths on the remote node are
different than the local node (e.g., if "/lib" is used on the local node, but "/lib64" is
used on the remote node), or if the installation paths are something other than a
subdirectory under a common prefix.
Note that executing ompi-submit via an absolute pathname is equivalent to specifying
--prefix without the last subdirectory in the absolute pathname to ompi-submit. For
example:
% /usr/local/bin/ompi-submit ...
is equivalent to
% ompi-submit --prefix /usr/local
Exported Environment Variables
All environment variables that are named in the form OMPI_* will automatically be exported
to new processes on the local and remote nodes. Environmental parameters can also be
set/forwarded to the new processes using the MCA parameter mca_base_env_list. The -x
option to ompi-submit has been deprecated, but the syntax of the MCA param follows that
prior example. While the syntax of the -x option and MCA param allows the definition of
new variables, note that the parser for these options are currently not very sophisticated
- it does not even understand quoted values. Users are advised to set variables in the
environment and use the option to export them; not to define them.
Setting MCA Parameters
The -mca switch allows the passing of parameters to various MCA (Modular Component
Architecture) modules. MCA modules have direct impact on MPI programs because they allow
tunable parameters to be set at run time (such as which BTL communication device driver to
use, what parameters to pass to that BTL, etc.).
The -mca switch takes two arguments: <key> and <value>. The <key> argument generally
specifies which MCA module will receive the value. For example, the <key> "btl" is used
to select which BTL to be used for transporting MPI messages. The <value> argument is the
value that is passed. For example:
ompi-submit -mca btl tcp,self -np 1 foo
Tells Open MPI to use the "tcp" and "self" BTLs, and to run a single copy of "foo" an
allocated node.
ompi-submit -mca btl self -np 1 foo
Tells Open MPI to use the "self" BTL, and to run a single copy of "foo" an allocated
node.
The -mca switch can be used multiple times to specify different <key> and/or <value>
arguments. If the same <key> is specified more than once, the <value>s are concatenated
with a comma (",") separating them.
Note that the -mca switch is simply a shortcut for setting environment variables. The
same effect may be accomplished by setting corresponding environment variables before
running ompi-submit. The form of the environment variables that Open MPI sets is:
OMPI_MCA_<key>=<value>
Thus, the -mca switch overrides any previously set environment variables. The -mca
settings similarly override MCA parameters set in the $OPAL_PREFIX/etc/openmpi-mca-
params.conf or $HOME/.openmpi/mca-params.conf file.
Unknown <key> arguments are still set as environment variable -- they are not checked (by
ompi-submit) for correctness. Illegal or incorrect <value> arguments may or may not be
reported -- it depends on the specific MCA module.
To find the available component types under the MCA architecture, or to find the available
parameters for a specific component, use the ompi_info command. See the ompi_info(1) man
page for detailed information on the command.
Running as root
The Open MPI team strongly advises against executing ompi-submit as the root user. MPI
applications should be run as regular (non-root) users.
Reflecting this advice, ompi-submit will refuse to run as root by default. To override
this default, you can add the --allow-run-as-root option to the ompi-submit command line.
Exit status
There is no standard definition for what ompi-submit should return as an exit status.
After considerable discussion, we settled on the following method for assigning the ompi-
submit exit status (note: in the following description, the "primary" job is the initial
application started by ompi-submit - all jobs that are spawned by that job are designated
"secondary" jobs):
• if all processes in the primary job normally terminate with exit status 0, we return 0
• if one or more processes in the primary job normally terminate with non-zero exit
status, we return the exit status of the process with the lowest MPI_COMM_WORLD rank to
have a non-zero status
• if all processes in the primary job normally terminate with exit status 0, and one or
more processes in a secondary job normally terminate with non-zero exit status, we (a)
return the exit status of the process with the lowest MPI_COMM_WORLD rank in the lowest
jobid to have a non-zero status, and (b) output a message summarizing the exit status of
the primary and all secondary jobs.
• if the cmd line option --report-child-jobs-separately is set, we will return -only- the
exit status of the primary job. Any non-zero exit status in secondary jobs will be
reported solely in a summary print statement.
By default, OMPI records and notes that MPI processes exited with non-zero termination
status. This is generally not considered an "abnormal termination" - i.e., OMPI will not
abort an MPI job if one or more processes return a non-zero status. Instead, the default
behavior simply reports the number of processes terminating with non-zero status upon
completion of the job.
However, in some cases it can be desirable to have the job abort when any process
terminates with non-zero status. For example, a non-MPI job might detect a bad result from
a calculation and want to abort, but doesn't want to generate a core file. Or an MPI job
might continue past a call to MPI_Finalize, but indicate that all processes should abort
due to some post-MPI result.
It is not anticipated that this situation will occur frequently. However, in the interest
of serving the broader community, OMPI now has a means for allowing users to direct that
jobs be aborted upon any process exiting with non-zero status. Setting the MCA parameter
"orte_abort_on_non_zero_status" to 1 will cause OMPI to abort all processes once any
process
exits with non-zero status.
Terminations caused in this manner will be reported on the console as an "abnormal
termination", with the first process to so exit identified along with its exit status.
EXAMPLES
Be sure also to see the examples throughout the sections above.
ompi-submit -np 4 -mca btl ib,tcp,self prog1
Run 4 copies of prog1 using the "ib", "tcp", and "self" BTL's for the transport of MPI
messages.
ompi-submit -np 4 -mca btl tcp,sm,self
--mca btl_tcp_if_include eth0 prog1
Run 4 copies of prog1 using the "tcp", "sm" and "self" BTLs for the transport of MPI
messages, with TCP using only the eth0 interface to communicate. Note that other BTLs
have similar if_include MCA parameters.
RETURN VALUE
ompi-submit returns 0 if all processes started by ompi-submit exit after calling
MPI_FINALIZE. A non-zero value is returned if an internal error occurred in ompi-submit,
or one or more processes exited before calling MPI_FINALIZE. If an internal error
occurred in ompi-submit, the corresponding error code is returned. In the event that one
or more processes exit before calling MPI_FINALIZE, the return value of the MPI_COMM_WORLD
rank of the process that ompi-submit first notices died before calling MPI_FINALIZE will
be returned. Note that, in general, this will be the first process that died but is not
guaranteed to be so.
SEE ALSO
MPI_Init_thread(3)