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mpiexec

Updated: January 13, 2014

Applies To: Microsoft HPC Pack 2008, Microsoft HPC Pack 2008 R2, Microsoft HPC Pack 2012, Microsoft HPC Pack 2012 R2, Windows HPC Server 2008, Windows HPC Server 2008 R2

Starts one or more Message Passing Interface (MPI) applications on an HPC cluster.

For examples of how to use this command, see Examples.

Syntax
mpiexec [/genv <env_var_name> <env_var_value>] 
[/gpath <path1>[;<path2>...]] [/gwdir <working_dir>] [/ghost <host_name>] 
[/gmachinefile <file_name>] [/genvlist <env_var1>[,<env_var2>...]] 
[/cores <num>] [/affinity] [/affinity_layout <algorithm>[:<target>]] [/exitcodes] [/priority {0|1|2|3|4}] 
[/port <port>] [/timeout <seconds>] [/job <string>] [/lines] 
[/t [(<filter1>,<filter2>...)]] [/tracefile <file_name>] 
[/tracemax <max_size>] [/debug [{0|1|2|3}]] [/np {<num>|*}] 
[/machinefile <file_name>] [/host <host_name>] 
[/hosts <num> <host1> [num1] <host2> [num2] ... <hostn> [numn]] 
[/wdir <working_dir>] [/env <env_var_name> <env_var_value>] 
[/path <path1>[;<path2>...]] <application1> [<application1_paramteters>] 
[: [<section2_parameters>] <application2> [<application2_parameters>]
[: [<section3_ parameters>] <application3> [<application3_parameters>]...]] 
mpiexec /configfile <file_name>
mpiexec {/? | /help | /?? | /help2 | /??? | /help3}
Parameters

 

Parameter Description

/genv <env_var_name> <env_var_value>

Sets an environment variable to the specified value for the applications in all sections of the mpiexec command. If you specify the value of an environment variable for a specific section by using the /env parameter and globally by using the /genv parameter, the setting that the /env parameter specifies for the section overrides the setting that the /genv parameter specifies.

To specify the values of multiple environment variables, specify the /genv parameter multiple times, once for each environment variable.

For a list of built-in environment variables that you can set with the /genv parameter, see MPICH Environment Variables.

/gpath <path1>[;<path2>...]

Specifies one or more paths to search on the target node for the applications in all sections of the mpiexec command. To specify multiple paths, separate paths with a semicolon. If the paths include spaces, enclose the paths in quotation marks ("). The value you specify for this parameter does not replace and is not appended to the PATH environment variable.

If you specify the search path for a specific section by using the /path parameter and globally by using the /gpath parameter, the setting that the /path parameter specifies for the section overrides the setting that the /gpath parameter specifies.

/gwdir <working_dir>

Specifies the working directory to use for the applications in all sections of the mpiexec command. This directory can have a local or a remote path. You can also specify this parameter as /gdir.

If you specify the working directory for a specific section by using the /wdir parameter and globally by using the /gwdir parameter, the setting that the /wdir parameter specifies for the section overrides the setting that the /gwdir parameter specifies.

/ghost <host_name>

Starts the applications in all sections of the mpiexec command on the specified node. If you also specify the /np * parameter or do not specify the /np parameter, the application uses one core on that node.

If the task that runs the mpiexec command is not allocated to the node that the /ghost parameter specifies, the command fails. Specify the resources and nodes for the task such that you ensure that the task is allocated to the node.

If you specify the /ghosts, /gmachinefile, or /np parameter with a numeric value, you cannot also specify the /ghost parameter.

If you specify the host for a specific section of the mpiexeccommand by using the /host parameter and globally by using the /ghost parameter, the setting that the /host parameter specifies for the section overrides the setting that the /ghost parameter specifies.

/gmachinefile <file_name>

Reads from the specified file a list of nodes on which to run the applications in all sections of the mpiexec command. The format for the file is one node name per line, optionally followed by the number of cores on which the application is allowed to run on that node.

You can designate lines or parts of lines in the file as comments by including a number sign (#) at the start of the comment. The comment then extends to end of the line. Empty lines in the file are ignored.

The file must exist on each node that is allocated to the task that runs the mpiexec command.

If the task that runs the mpiexec command is not allocated to one of the nodes listed in the file that the /gmachinefile parameter specifies, the command fails. Specify the resources and nodes for the task such that you ensure that the task is allocated to all of the nodes in the file.

If you also specify the /np * option or do not specify the /np option, the application uses the sum of the number of cores that are specified for all of the nodes in the file. If you specify a value for the /np option that is less than the sum of the number of cores that are specified for all of the nodes in the file, the application runs only the total number of cores that the /np option specifies. Cores on the nodes are used in the order in which the file specifies the nodes.

If you specify the /ghost parameter, you cannot also specify the /gmachinefile parameter.

If you specify the file that lists the nodes on which to run the application for a specific section of the mpiexec command by using the /machinefile parameter and globally for the applications in all sections of the mpiexec command by using the /gmachinefile parameter, the setting that the /machinefile parameter specifies for the section overrides the setting that the /gmachinefile parameter specifies.

/configfile <file_name>

Reads the remaining parameters for the mpiexec command line from the specified file. The lines in the file are command-line sections in the following format:

[<section_parameters>] <application> [<application_parameters>]

You can include a command in the file that spans multiple lines by ending each line of the command except the last line with a backslash (\). You can designate lines or parts of lines in the file as comments by including a number sign (#) at the start of the comment. The comment then extends to end of the line. Empty lines in the file are ignored.

If you run the mpiexec command as a task in a job, the file must exist on each node that is allocated to the task. If you run the mpiexec command by using the clusrun command, the file must exist on each node on which clusrun runs mpiexec.

/np {<num>|*}

Specifies the number of processes on which to run the application that is specified in the same section of the mpiexec command as the /np parameter. If you specify an asterisk (*), the MPI application uses all available cores unless more than one section is specified, in which case the MPI application uses the remaining available cores. The absence of the /np parameter is equivalent to /np *.

You can also specify this parameter as /n.

If you specify the /hosts parameter, you cannot also specify the /np or /n parameter.

/machinefile <file_name>

Reads from the specified file a list of nodes on which to run the application that is specified in the same section of the mpiexec command as the /machinefile parameter. The format for the file is one node name per line, optionally followed by the number of cores on which the application is allowed to run on that node.

You can designate lines or parts of lines in the file as comments by including a number sign (#) at the start of the comment. The comment then extends to end of the line. Empty lines in the file are ignored.

The file must exist on each node that is allocated to the task that runs the mpiexec command.

If the task that runs the mpiexec command is not allocated to one of the nodes listed in the file that the /machinefile parameter specifies, the command fails. Specify the resources and nodes for the task such that you ensure that the task is allocated to all of the nodes in the file.

If you also specify the /np * option or do not specify the /np option, the application uses the sum of the number of cores that are specified for all of the nodes in the file. If you specify a value for the /np option that is less than the sum of the number of cores that are specified for all of the nodes in the file, the application runs only the total number of cores that the /np option specifies. Cores on the nodes are used in the order in which the file specifies the nodes.

If you specify the /host or /hosts parameter, you cannot also specify the /machinefile parameter.

If you specify the file the lists the nodes on which to run the application for a specific section of the mpiexec command by using the /machinefile parameter and globally for the applications in all sections of the mpiexec command by using the /gmachinefile parameter, the setting that the /machinefile parameter specifies for the section overrides the setting that the /gmachinefile parameter specifies.

/host <host_name>

Starts the application that is specified in the same section of the mpiexec command as the /host parameter on the specified node. If you also specify /np * parameter or do not specify the /np parameter, the application uses one core on that node.

If the task that runs the mpiexec command is not allocated to the node that the /host parameter specifies, the command fails. Specify the resources and nodes for the task such that you ensure that the task is allocated to the node.

If you specify the /hosts, /machinefile, or /np parameter with a numeric value, you cannot also specify the /host parameter.

If you specify the host for a specific section of the mpiexec command by using the /host parameter and globally by using the /ghost parameter, the setting that the /host parameter specifies for the section overrides the setting that the /ghost parameter specifies.

/hosts <num> <host1> [num1] <host2> [num2] ... <hostn> [numn]

Specifies the number of nodes on which you want to run the application that is specified in the same section of the mpiexec command as the /hosts parameter, then lists the names of each node and optionally lists the number of processes to run on that node.

If the task that runs the mpiexec command is not allocated to one of the nodes that the /hosts parameter specifies, the command fails. Specify the resources and nodes for the task such that you ensure that the task is allocated to all of the nodes in the list.

If you specify the /host or /machinefile parameter, you cannot also specify the /hosts parameter.

/cores <num>

Specifies the numbers of cores to use on each node. This option overrides the number of cores that are specified for each node in the /hosts parameter or in the file that is specified by the /machinefile parameter. This override applies to all sections of the mpiexec command.

You can also specify this parameter as /c.

/affinity

Sets the affinity mask for each of the processes that the mpiexec command starts to a single core.

noteNote
This setting should only be used if a job is using nodes exclusively. If jobs are sharing a node (not running exclusively), this affinity setting mechanism might assign the same affinity mask to all jobs on the node. If you want to share nodes, you must either set affinity explicitly, or allow the Job Scheduler to manage affinity. For more information, see job scheduler affinity settings.

For more information about affinity, see Performance Tuning a Windows HPC Cluster for Parallel Applications.

/affinity_layout

Specifies the algorithm used to distribute rank processes to the compute cores. Specifying a different algorithm will change the cores that each rank process runs on. Changing the target allows larger units of cores to be assigned per rank process.

noteNote
Target is typically used only for multithreaded applications.

The following table contains values for the algorithm.

 

Algorithm Description

Disabled = 0

Does not assign affinity to any process

Spread = 1

Distributes the processes as far as possible (default)

Sequential = 2

Distributes the processes per core sequentially

Balanced = 3

Distribute the processes over the available NUMA nodes

The following table contains values for the target.

 

Target Description

L

Assigns each process to a logical core

P

Assigns each process to a physical core

N

Assigns each process to a NUMA node

noteNote
This parameter was introduced in HPC Pack 2012 and is not supported in previous versions.

/wdir <working_dir>

Specifies the working directory to use for the application specified in the same section of the mpiexec command as the /wdir parameter. This directory can have a local or a remote path. You can also specify this parameter as /dir.

If you specify the working directory for a specific section by using the /wdir parameter and globally by using the /gwdir parameter, the setting that the /wdir parameter specifies for the section overrides the setting that the /gwdir parameter specifies.

/env <env_var_name> <env_var_value>

Sets an environment variable for the application that is specified in the same section of the mpiexec command as the /env parameter. If you specify the value of an environment variable for a specific section by using the /env parameter and globally by using the /genv parameter, the setting that the /env parameter specifies for the section overrides the setting that the /genv parameter specifies.

To specify the values of multiple environment variables, specify the /env parameter multiple times, once for each environment variable.

For a list of built-in environment variables that you can set with the /env parameter, see MPICH Environment Variables.

/genvlist <env_var1>[,<env_var2>...]

Passes the values of the specified environment variables to the processes that mpiexec starts. The list is a comma-separated list of environment variable names.

For a list of built-in environment variables that you can use with the /genvlist parameter, see MPICH Environment Variables.

/exitcodes

Prints the exit codes of the processes that mpiexec started as part of standard output at the end of the run.

/priority {0|1|2|3|4}

Sets the priority for the processes that mpiexec starts. The default priority is 2. The following table describes the possible values:

 

Value Description

0

Idle

1

Below normal

2

Normal

3

Above normal

4

High

/port <port>

Specifies the port on which the smpd.exe process listens. You can also specify this parameter as /p.

/path <path1>[;<path2>...]

Specifies one or more paths to search on the target node for the application that is specified in the same section of the mpiexec command as the /path parameter. To specify multiple paths, separate paths with a semicolon. If the paths include spaces, enclose the paths in quotation marks ("). The value that you specify for this parameter does not replace and is not appended to the PATH environment variable.

If you specify the search path for a specific section by using the /path parameter and globally by using the /gpath parameter, the setting that the /path parameter specifies for the section overrides the setting that the /gpath parameter specifies.

/timeout <seconds>

Sets the amount of time that job that runs the mpiexec command should run before timing out, in seconds.

/job <string>

Associates an MPI job with a job that is created by the Windows HPC Job Scheduler Service. The string is passed to mpiexec by the HPC Node Manager Service.

/lines

Prefixes each line in the output of the mpiexec command with the rank of the process that generated the line. You can also specify this parameter as /l.

/trace [(<filter1>,<filter2>...)]

ImportantImportant

Traces Microsoft-Message Passing Interface (MS-MPI) events for the application. If you do not specify any filters, the mpiexec command traces all MS-MPI events for the application. Optionally, you can specify trace filters to enable only trace events of interest. List the event filter names, or their equivalent hexadecimal values, by using a comma-separated list enclosed in parentheses.

ImportantImportant
While this type of tracing can be useful for a very simple test application, in most practical applications, this method generates such a large trace file that it is not very useful. To control tracing and create manageable trace files, use an Event Tracing for Windows (ETW) tool such as Xperf or Logman to turn on tracing only for the part you need.

By default, trace logs are written to the directory for the user profile on each node. Use the /tracefile parameter to specify an alternative trace file.

The following table shows the event filter names and equivalent hexadecimal values that you can include in the list of filters:

 

Name Hexadecimal value Description

all

0xffffffff

All API and communication events

api

0x00007fff

All API events

pt2pt

0x00000001

Point-to-point APIs

poll

0x00000002

Point-to-point polling APIs, such as MPI_Iprobe and MPI_TestXXX

coll

0x00000004

Collective APIs

rma

0x00000008

One-sided APIs

comm

0x00000010

Communication APIs

errh

0x00000020

Error handler APIs

group

0x00000040

Group APIs

attr

0x00000080

Attribute APIs

dtype

0x00000100

Data type APIs

io

0x00000200

Input/output APIs

topo

0x00000400

Topology APIs

spawn

0x00000800

Dynamic process APIs

init

0x00001000

Initialization APIs

info

0x00002000

Information APIs

misc

0x00004000

Miscellaneous APIs

interconn

0x000f8000

All interconnectivity communication

icsock

0x00008000

Socket interconnectivity communication

icshm

0x00010000

Shared memory interconnectivity communication

icnd

0x00020000

NetworkDirect interconnectivity communication

You can also specify this parameter as /t.

noteNote
This parameter is deprecated as of HPC Pack 2008 R2 with Service Pack 3 (SP3).

/tracefile <file_name>

Specifies the name of file to use for the trace log, including the path. The default file is %USERPROFILE%\mpi_trace_job_identifier.task_identifier.subtask_identifier.etl. You can also specify this parameter as /tf.

noteNote
This parameter is deprecated as of HPC Pack 2008 R2 with Service Pack 3 (SP3).

/tracemax <max_size>

Specifies the maximum size of the trace log file, in megabytes. You must have at least max_size megabytes of free space available on the drive that you specify for the trace file.

The binary tracing data is written by using a circular buffer, so when the data exceeds the maximum size of the file, the tracing data is overwritten starting at the beginning of the file. As a result, the tracing log file always contains the most recent max_size megabytes of tracing data from the MPI job.

Each binary record in the trace log file has a time stamp, so that log file viewers can display the information in chronological order regardless of the wrapping cause when the tracing data is overwritten.

The default value for this parameter is 10240. Specify 0 to allow the creation of a trace log file of unrestricted size.

You can also specify this parameter as /tm.

noteNote
This parameter was introduced in HPC Pack 2008 R2. It is deprecated as of HPC Pack 2008 R2 with Service Pack 3 (SP3).

/debug [{0|1|2|3}]

Prints the specified level of debugging information to standard error. If you specify the /debug option without a value, mpiexec behaves as if you specified as value of 2. The following table describes the possible debugging levels.

 

Value Description

0

No debugging information is displayed.

1

Information about errors is displayed.

2

Extensive debugging information is displayed.

3

Both errors and extensive debugging information are displayed.

You can also specify this parameter as /d.

<sectionN_parameters>

Specifies parameters that apply only to the section of the mpiexec command in which they occur, and includes the following parameters:

  • /env

  • /path

  • /wdir

  • /host

  • /hosts

  • /machinefile

  • /np

The Syntax section explicitly lists these parameters for the first section, and uses the <sectionN_parameters> placeholder for the additional sections. For information about sections in an mpiexec command, see the description for the <applicationN> [<applicationN_parameters>] parameter.

<applicationN> [<applicationN_parameters>]

Specifies the MPI applications that you want to start and any necessary parameters for those applications. You can specify more than one application by including multiple colon-separated sections in the mpiexec command.

If you include multiple sections to specify multiple applications, the applications need to have compatible requirements for the ranks on which the applications need to run and the roles that the applications serve on those ranks. For example, you can use two sections to specify a master process that needs to run on rank 0 and a subordinate process that does not need to run on rank 0.

/?

Displays Help for commonly used parameters of the mpiexec command at the command prompt.

You can also specify this parameter as /help.

/??

Displays Help descriptions for all parameters of the mpiexec command and examples of the mpiexec command at the command prompt.

You can also specify this parameter as /help2.

/???

Displays Help for the environment variables that you can use with the mpiexec command at the command prompt.

You can also specify this parameter as /help3.

Remarks

In most cases, you should run the mpiexec command by specifying it in a task for a job. You can only run mpiexec directly at a command prompt if the application requires only a single node and you run it on the local computer, instead of specifying nodes with the /host, /hosts, or /machinefile parameters.

If you run the mpiexec command by using the clusrun command, the mpiexec command behaves as if you specified the command locally at the command prompt on each node on which clusrun runs the mpiexec command. In this case, you again can only run the mpiexec command if the application requires only a single node, and only if you do not specify other nodes by using the parameters of the mpiexec command.

Examples

To run four application1 processes on the local host with four cores, use either of the following commands:

mpiexec application1
mpiexec /np * application1

To run one master process and three subordinate processes on the local host with four cores, use the following command, in which the absence of /np from the second section is equivalent to /np *:

mpiexec /np 1 master : subordinate

To run one master process and 31 subordinate processes on the hosts listed in a myhosts.txt file that lists four hosts with eight cores each, use the following command:

mpiexec /gmachinefile myhosts.txt /np 1 master : subordinate

To trace the point-to-point and collective MPI calls that the two application1 processes are making and the interconnectivity communication that is generated by MPI, and limit the maximum size of the tracing file to 20,480 megabytes, use the following command:

mpiexec /trace (pt2pt,coll,interconn) /tracemax 20480 /np 2 application1

To run the application1 process on the hosts that are listed in a myhosts.txt file and include a connectivity table in the standard output, use the following command:

mpiexec /machinefile myhosts.txt /env MPICH_CONNECTIVITY_TABLE 1 application1