Intel® MPI Library Developer Reference for Linux* OS

ID 768732
Date 3/22/2024
Public

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Document Table of Contents

Global Hydra Options

This section describes the global options of the Intel® MPI Library's Hydra process manager. Global options are applied to all arguments sets in the launch command. Argument sets are separated by a colon ':'.

-tune <filename>

Use this option to specify the file name that contains the tuning data in a binary format.

-usize <usize>

Use this option to set MPI_UNIVERSE_SIZE, which is available as an attribute of the MPI_COMM_WORLD.

<size> Define the universe size
SYSTEM Set the size equal to the number of cores passed to mpiexec through the hostfile or the resource manager.
INFINITE Do not limit the size. This is the default value.
<value> Set the size to a numeric value ≥ 0.

-hostfile <hostfile> or -f <hostfile>

Use this option to specify host names on which to run the application. If a host name is repeated, this name is used only once.

See also the I_MPI_HYDRA_HOST_FILE environment variable for more details.

NOTE:
Use the following options to change the process placement on the cluster nodes:
  • Use the -perhost, -ppn, and -grr options to place consecutive MPI processes on every host using the round robin scheduling.

  • Use the -rr option to place consecutive MPI processes on different hosts using the round robin scheduling.

-machinefile <machine file> or -machine <machine file>

Use this option to control process placement through a machine file. To define the total number of processes to start, use the -n option. For example:

$ cat ./machinefile
node0:2
node1:2
node0:1

-hosts-group

Use this option to set node ranges using brackets, commas, and dashes (like in Slurm* Workload Manager).

For more details, see the I_MPI_HYDRA_HOST_FILE environment variable in Hydra Environment Variables.  

-silent-abort

Use this option to disable abort warning messages.

For more details, see the I_MPI_SILENT_ABORT environment variable in Hydra Environment Variables.  

-nameserver

Use this option to specify the nameserver in the hostname:port format.

For more details, see the I_MPI_HYDRA_NAMESERVER environment variable in Hydra Environment Variables.  

-genv <ENVVAR> <value>

Use this option to set the <ENVVAR> environment variable to the specified <value> for all MPI processes.

-genvall

Use this option to enable propagation of all environment variables to all MPI processes.

-genvnone

Use this option to suppress propagation of any environment variables to any MPI processes.

NOTE:
The option does not work for localhost.

-genvexcl <list of env var names>

Use this option to suppress propagation of the listed environment variables to any MPI processes.

-genvlist <list>

Use this option to pass a list of environment variables with their current values. <list> is a comma separated list of environment variables to be sent to all MPI processes.

-pmi-connect <mode>

Use this option to choose the caching mode of process management interface (PMI) message. Possible values for <mode> are:

<mode> The caching mode to be used
nocache Do not cache PMI messages.
cache Cache PMI messages on the local pmi_proxy management processes to minimize the number of PMI requests. Cached information is automatically propagated to child management processes.
lazy-cache cache mode with on-request propagation of the PMI information.
alltoall Information is automatically exchanged between all pmi_proxy before any get request can be done. This is the default mode.

See the I_MPI_HYDRA_PMI_CONNECT environment variable for more details.

-perhost <# of processes >, -ppn <# of processes >, or -grr <# of processes>

Use this option to place the specified number of consecutive MPI processes on every host in the group using round robin scheduling. See the I_MPI_PERHOST environment variable for more details.

NOTE:
When running under a job scheduler, these options are ignored by default. To be able to control process placement with these options, disable the I_MPI_JOB_RESPECT_PROCESS_PLACEMENT variable.

-rr

Use this option to place consecutive MPI processes on different hosts using the round robin scheduling. This option is equivalent to "-perhost 1". See the I_MPI_PERHOST environment variable for more details.

-trace [<profiling_library>] or -t [<profiling_library>]

Use this option to profile your MPI application with Intel® Trace Collector using the indicated <profiling_library>. If you do not specify <profiling_library>, the default profiling library libVT.so is used.

Set the I_MPI_JOB_TRACE_LIBS environment variable to override the default profiling library.

-trace-imbalance

Use this option to profile your MPI application with Intel® Trace Collector using the libVTim.so library.

-aps

Use this option to collect statistics from your MPI application using Application Performance Snapshot. The collected data includes hardware performance metrics, memory consumption data, internal MPI imbalance and OpenMP* imbalance statistics. When you use this option, a new folder aps_result_<date>-<time> with statistics data is generated. You can analyze the collected data with the aps utility, for example:

$ mpirun -aps -n 2 ./myApp
$ aps aps_result_20171231_235959

NOTE:
  1. To use this option, set up the Application Performance Snapshot environment beforehand. See the tool's https://www.intel.com/content/www/us/en/docs/vtune-profiler/user-guide-application-snapshot-linux/current/overview.htmlUser Guide.
  2. If you use the options -trace or -check_mpi, the -aps option is ignored.

-mps

Use this option to collect only MPI and OpenMP* statistics from your MPI application using Application Performance Snapshot. Unlike the -aps option, -mps doesn't collect hardware metrics. The option is equivalent to:

$ mpirun -n 2 aps -c mpi,omp ./myapp

-trace-pt2pt

Use this option to collect the information about point-to-point operations using Intel® Trace Analyzer and Collector. The option requires that you also use the -trace option.

-trace-collectives

Use this option to collect the information about collective operations using Intel® Trace Analyzer and Collector. The option requires that you also use the -trace option.

NOTE:

Use the -trace-pt2pt and -trace-collectives to reduce the size of the resulting trace file or the number of message checker reports. These options work with both statically and dynamically linked applications.

-configfile <filename>

Use this option to specify the file <filename> that contains the command-line options with one executable per line. Blank lines and lines that start with '#' are ignored. Other options specified in the command line are treated as global.

You can specify global options in configuration files loaded by default (mpiexec.conf in <installdir>/etc, ~/.mpiexec.conf, and mpiexec.conf in the working directory). The remaining options can be specified in the command line.

-branch-count <num>

Use this option to restrict the number of child management processes launched by the Hydra process manager, or by each pmi_proxy management process.

See the I_MPI_HYDRA_BRANCH_COUNT environment variable for more details.

-pmi-aggregate or -pmi-noaggregate

Use this option to switch on or off, respectively, the aggregation of the PMI requests. The default value is -pmi-aggregate, which means the aggregation is enabled by default.

See the I_MPI_HYDRA_PMI_AGGREGATE environment variable for more details.

-gdb

Use this option to run an executable under GDB* (GNU debugger). You can use the following command:

$ mpiexeс.hydra -gdb -n <# of processes> <executable>

-gdba <pid>

Use this option to attach the GNU* debugger to the existing MPI job. You can use the following command:

$ mpiexec.hydra -gdba <pid>

-nolocal

Use this option to avoid running the <executable> on the host where mpiexec.hydra is launched. You can use this option on clusters that deploy a dedicated main node for starting the MPI jobs and a set of dedicated compute nodes for running the actual MPI processes.

-hosts <nodelist>

Use this option to specify a particular <nodelist> on which the MPI processes should be run. For example, the following command runs the executable a.out on the hosts host1 and host2:

$ mpiexec.hydra -n 2 -ppn 1 -hosts host1,host2 ./a.out
NOTE:
If <nodelist> contains only one node, this option is interpreted as a local option. See Local Options for details.

-iface <interface>

Use this option to choose the appropriate network interface. For example, if the IP emulation of your InfiniBand* network is configured to ib0, you can use the following command.

$ mpiexec.hydra -n 2 -iface ib0 ./a.out

See the I_MPI_HYDRA_IFACE environment variable for more details.

-demux <mode>

Use this option to set the polling mode for multiple I/O. The default value is poll.

Arguments

<spec> Define the polling mode for multiple I/O
poll Set poll as the polling mode. This is the default value.
select Set select as the polling mode.

See the I_MPI_HYDRA_DEMUX environment variable for more details.

-enable-x  or -disable-x

Use this option to control the Xlib* traffic forwarding. The default value is -disable-x, which means the Xlib traffic is not forwarded.

-l, -prepend-rank

Use this option to insert the MPI process rank at the beginning of all lines written to the standard output.

-ilp64

Use this option to preload the ILP64 interface.

-s <spec>

Use this option to direct standard input to the specified MPI processes.

Arguments

<spec> Define MPI process ranks
all Use all processes.
none

Do not direct standard output to any processes.

<l>,<m>,<n> Specify an exact list and use processes <l>, <m> and <n> only. The default value is zero.
<k>,<l>-<m>,<n> Specify a range and use processes <k>, <l> through <m>, and <n>.

-noconf

Use this option to disable processing of the mpiexec.hydra configuration files.

-ordered-output

Use this option to avoid intermingling of data outut from the MPI processes. This option affects both the standard output and the standard error streams.

NOTE:
When using this option, end the last output line of each process with the end-of-line '\n' character. Otherwise the application may stop responding.

-path <directory>

Use this option to specify the path to the executable file.

-tmpdir <dir>

Use this option to set a directory for temporary files. See the I_MPI_TMPDIR environment variable for more details.

-version or -V

Use this option to display the version of the Intel® MPI Library.

-info

Use this option to display build information of the Intel® MPI Library. When this option is used, the other command line arguments are ignored.

-localhost

Use this option to explicitly specify the local host name for the launching node.

-rmk <RMK>

Use this option to select a resource management kernel to be used. Intel® MPI Library only supports pbs.

See the I_MPI_HYDRA_RMK environment variable for more details.

-outfile-pattern <file>

Use this option to redirect stdout to the specified file.

-errfile-pattern <file>

Use this option to redirect stderr to the specified file.

-gpath <path>

Use this option to specify the path to the executable file.

-gwdir <dir>

Use this option to specify the working directory in which the executable file runs.

-gumask <umask>

Use this option to perform the "umask <umask>" command for the remote executable file.

-gdb-ia

Use this option to run processes under Intel® architecture specific GNU* debugger.

-prepend-pattern

Use this option to specify the pattern that is prepended to the process output.

-prepend-timestamp

Use this option to prepend timestamp to stdout or stderr line.

-verbose or -v

Use this option to print debug information from mpiexec.hydra, such as:

  • Service processes arguments

  • Environment variables and arguments passed to start an application

  • PMI requests/responses during a job life cycle

See the I_MPI_HYDRA_DEBUG environment variable for more details.

-print-rank-map

Use this option to print out the MPI rank mapping.

-print-all-exitcodes

Use this option to print the exit codes of all processes.

-bootstrap <bootstrap server>

Use this option to select a built-in bootstrap server to use. A bootstrap server is the basic remote node access mechanism that is provided by the system. Hydra supports multiple runtime bootstrap servers such as ssh, rsh, pdsh, fork, persist,slurm, ll, lsf, or sge to launch MPI processes. The default bootstrap server is ssh. By selecting slurm, ll, lsf, or sge, you use the corresponding srun, llspawn.stdio, blaunch, or qrsh internal job scheduler utility to launch service processes under the respective selected job scheduler (Slurm*, LoadLeveler*, LSF*, and SGE*).

Arguments

<arg> String parameter
ssh Use secure shell. This is the default value.
rsh Use remote shell.
pdsh Use parallel distributed shell.
pbs Use Torque* pbsdsh command.
pbsdsh Alias for pbs bootstrap.
fork Use fork call.
persist Use Hydra persist server. See below for details.
slurm Use Slurm* srun command.
ll Use LoadLeveler* llspawn.stdio command.
lsf Use LSF blaunch command.
sge Use Univa* Grid Engine* qrsh command.

See I_MPI_HYDRA_BOOTSTRAP for details.

-bootstrap-exec <bootstrap server>

Use this option to set the executable to be used as a bootstrap server. The default bootstrap server is ssh. For example:

$ mpiexec.hydra -bootstrap-exec <bootstrap_server_executable> -f hosts -env <VAR1> <VAL1> -n 2 ./a.out

See I_MPI_HYDRA_BOOTSTRAP for more details.

-bootstrap-exec-args <args>

Use this option to provide the additional parameters to the bootstrap server executable file.

$ mpiexec.hydra -bootstrap-exec-args <arguments> -n 2 ./a.out

For tight integration with the Slurm* scheduler (including support for suspend/resume), use the method outlined on the Slurm page here: http://www.schedmd.com/slurmdocs/mpi_guide.html#intel_mpi

See I_MPI_HYDRA_BOOTSTRAP_EXEC_EXTRA_ARGS for more details.

-v6

Use this option to force using the IPv6 protocol.