Operation and Use, Volume 1 Using the Parallel Operating Environment

poe

NAME

poe - Invokes the Parallel Operating Environment (POE) for loading and executing programs on remote processor nodes.

SYNOPSIS

poe [-h] [program] [program_options]...
[-adapter_use adapter_specifier]
[-cpu_use cpu_specifier]
[-euidevice device_specifier]
[-euilib {ip | us}]
[-euilibpath path_specifier]
[{-hostfile | -hfile} host_file_name]
[-pmd_version {2 | 3}]
[-procs partition_size]
[-pulse interval]
[-resd {yes | no}]
[-retry retry_interval]
[-retrycount retry_count]
[-msg_api {MPI | LAPI | MPI,LAPI}]
[-rmpool pool_ID]
[-nodes number_of_nodes]
[-tasks_per_node number_of_tasks]
[-savehostfile output_file_name]
[-cmdfile commands_file]
[-llfile loadleveler_job_command_file_name]
[-newjob {yes | no}]
[-pgmmodel {spmd | mpmd}]
[-save_llfile output_file_name]
[-labelio {yes | no}]
[-stdinmode {all | none | task_ID}]
[-stdoutmode {unordered | ordered | task_ID}]
[{-infolevel | -ilevel} message_level]
[-pmdlog {yes | no}]
[-buffer_mem memory_size]
[-clock_source {AIX | SWITCH}]
[-css_interrupt {yes | no}]
[-eager_limit size_limit]
[-hints_filtered {yes | no}]
[-intrdelay delay_parameter]
[-max_typedepth maximum_depth]
[-ionodefile io_node_file_name]
[-shared_memory {yes | no}]
[-use_flow_control {yes | no}]
[-thread_stacksize stacksize]
[-single_thread {no | yes}]
[-wait_mode {poll | yield | sleep}]
[-polling_interval interval]
[-retransmit_interval interval]
[-io_buffer_size buffer_size]
[-io_errlog {yes | no}]
[-coredir directory_prefix_string | none]
[-corefile_format { lightweight_corefile_name | STDERR }]
[-euidevelop {yes | no | deb | min | nor}]
[-pmlights number_of_lights]
[-usrport port_ID] [fence_string additional_options]

The poe command invokes the Parallel Operating Environment for loading and executing programs on remote processor nodes. The operation of POE is influenced by a number of POE environment variables. The flag options on this command are each used to temporarily override one of these environment variables. User program_options can be freely interspersed with the flag options. If no program is specified, POE will either prompt you for programs to load, or, if the MP_CMDFILE environment variable is set, will load the partition using the specified commands file.

FLAGS

The -h flag, when used, must appear immediately after poe, and causes the poe man page, if it exists, to be printed to the screen.

The remaining flags you can specify on this command are used to temporarily override POE environment variables. For more information on valid values, and on what a particular flag sets, refer to the description of its associated environment variable in the ENVIRONMENT VARIABLES section. The following flags are grouped by function.

The following Partition Manager control flags override the associated environment variables.

-adapter_use: MP_ADAPTER_USE
-cpu_use: MP_CPU_USE
-euidevice: MP_EUIDEVICE
-euilib: MP_EUILIB
-euilibpath: MP_EUILIBPATH
-hostfile or -hfile: MP_HOSTFILE
-pmd_version: MP_PMD_VERSION
-procs: MP_PROCS
-pulse: MP_PULSE
-resd: MP_RESD
-retry: MP_RETRY
-retrycount: MP_RETRYCOUNT
-msg_api: MP_MSG_API
-rmpool: MP_RMPOOL
-nodes: MP_NODES
-tasks_per_node: MP_TASKS_PER_NODE
-savehostfile: MP_SAVEHOSTFILE

The following Job Specification flags override the associated environment variables.

-cmdfile: MP_CMDFILE
-llfile: MP_LLFILE
-newjob: MP_NEWJOB
-pgmmodel: MP_PGMMODEL
-save_llfile: MP_SAVE_LLFILE

The following I/O Control flags override the associated environment variables.

-labelio: MP_LABELIO
-stdinmode: MP_STDINMODE
-stdoutmode: MP_STDOUTMODE

The following generation of diagnostic information flags override the associated environment variables.

-infolevel or -ilevel: MP_INFOLEVEL
-pmdlog: MP_PMDLOG

The following Message Passing flags override the associated environment variables.

-buffer_mem: MP_BUFFER_MEM
-clock_source: MP_CLOCK_SOURCE
-css_interrupt: MP_CSS_INTERRUPT
-eager_limit: MP_EAGER_LIMIT
-hints_filtered: MP_HINTS_FILTERED
-intrdelay: MP_INTRDELAY
-max_typedepth: MP_MAX_TYPEDEPTH
-ionodefile: MP_IONODEFILE
-shared_memory: MP_SHARED_MEMORY
-use_flow_control: MP_USE_FLOW_CONTROL
-thread_stacksize: MP_THREAD_STACKSIZE
-single_thread: MP_SINGLE_THREAD
-wait_mode: MP_WAIT_MODE
-polling_interval: MP_POLLING_INTERVAL
-retransmit_interval: MP_RETRANSMIT_INTERVAL
-io_buffer_size: MP_IO_BUFFER_SIZE
-io_errlog: MP_IO_ERRLOG

The following corefile generation flags override the associated environment variables.

-coredir: MP_COREDIR
-corefile_format: MP_COREFILE_FORMAT

The following are miscellaneous flags:

-euidevelop: Overrides the MP_EUIDEVELOP environment variable.
-pmlights: Determines the number of lights displayed (per row) on the Program Marker Array. This overrides the MP_PMLIGHTS environment variable. For more information on the Program Marker Array, refer to the manual page for the pmarray command.
-usrport: Overrides the MP_USRPORT environment variable.

DESCRIPTION

The poe command invokes the Parallel Operating Environment for loading and executing programs on remote nodes. You can enter it at your home node to:

load and execute an SPMD program on all nodes of your partition.
individually load the nodes of your partition with an MPMD job.
load and execute a series of SPMD and MPMD programs, in individual job steps, on the same partition.
run non-parallel programs on remote nodes.

The operation of POE is influenced by a number of POE environment variables. The flag options on this command are each used to temporarily override one of these environment variables. User program_options can be freely interspersed with the flag options, and additional_options not to be parsed by POE can be placed after a fence_string defined by the MP_FENCE environment variable. If no program is specified, POE will either prompt you for programs to load, or, if the MP_CMDFILE environment variable is set, will load the partition using the specified commands file.

The environment variables and flags that influence the operation of this command fall into distinct categories of function. They are:

Partition Manager control. The environment variables and flags in this category determine the method of node allocation, message passing mechanism, and the PULSE monitor function.
Job specification. The environment variables and flags in this category determine whether or not the Partition Manager should maintain the partition for multiple job steps, whether commands should be read from a file or STDIN, and how the partition should be loaded.
I/O control. The environment variables and flags in this category determine how I/O from the parallel tasks should be handled. These environment variables and flags set the input and output modes, and determine whether or not output is labeled by task id.
Generation of diagnostic information. The environment variables and flags in this category enable you to generate diagnostic information that may be required by the IBM Support Center in resolving PE-related problems.
Message Passing Interface. The environment variables and flags in this category enable you to specify values for tuning message passing applications.
Corefile generation. The environment variables and flags in this category govern aspects of corefile generation including the directory name into which corefiles will be saved, or the corefile format (standard AIX or lightweight).
Miscellaneous. The additional environment variables and flags in this category enable additional error checking, and set a dispatch priority class for execution.

ENVIRONMENT VARIABLES

The environment variable descriptions in this section are grouped by function.

The following environment variables are associated with Partition Manager control.

MP_ADAPTER_USE: Determines how the node's adapter should be used. The US communication subsystem library does not require dedicated use of the SP switch on the node. Adapter use will be defaulted, as in Table 4, but shared usage may be specified. Valid values are dedicated and shared. If not set, the default is dedicated for US jobs, or shared for IP jobs. The value of this environment variable can be overridden using the -adapter_use flag.
MP_CPU_USE: Determines how the node's CPUs should be used. The US communication subsystem library does not require unique CPU use on the node. CPU use will be defaulted, as in Table 4, but multiple use may be specified. Valid values are multiple and unique. If not set, the default is unique for US jobs, or multiple for IP jobs. The value of this environment variable can be overridden using the -cpu_use flag.
MP_EUIDEVICE: Determines the adapter set to use for message passing. Valid values are en0 (for Ethernet), fi0 (for FDDI), tr0 (for token-ring), css0 (for the SP system's high performance switch feature), and csss (for the SP switch 2 high performance adapter).
MP_EUILIB: Determines the communication subsystem library implementation to use for communication - either the IP communication subsystem or the US communication subsystem. In order to use the US communication subsystem, you must have an SP system configured with its high performance switch feature. Valid, case-sensitive, values are ip (for the IP communication subsystem) or us (for the US communication subsystem). The value of this environment variable can be overridden using the -euilib flag.
MP_EUILIBPATH: Determines the path to the message passing and communication subsystem libraries. This only needs to be set if an alternate library path is desired. Valid values are any path specifier. The value of this environment variable can be overridden using the -euilibpath flag.
MP_HOSTFILE: Determines the name of a host list file for node allocation. Valid values are any file specifier. If not set, the default is host.list in your current directory. The value of this environment variable can be overridden using the -hostfile or -hfile flags.
MP_PMD_VERSION: Determines which version of the partition manager daemon should be used. It is intended for situations where you need to submit a parallel job from a POE version 3 node to a set of nodes that have not yet been upgraded to version 3. Valid values are 2 (use the version 2 partition manager daemon -- pmv2) and 3 (use the version 3 partition manager daemon -- pmv3). If not set, the default is to use the version 3 partition manager daemon. You can override this environment variable with the -pmd_version flag.
MP_PROCS: Determines the number of program tasks. Valid values are any number from 1 to 4096. If not set, the default is 1. The value of this environment variable can be overridden using the -procs flag.
MP_PULSE: The interval (in seconds) at which POE checks the remote nodes to ensure that they are communicating with the home node. The default interval is 600 seconds (10 minutes). To disable the pulse function, specify an interval of 0 (zero) seconds. The pulse function is automatically disabled when running the pdbx debugger. You can override the value of this environment variable with the -pulse flag.
MP_REMOTEDIR: Specifies the name of a script which echoes the name of the current directory to be used on the remote nodes. By default, the current directory is the current directory at the time that POE is run. You may need to specify this if the AutoMount Daemon is used to mount user file systems, and the user is not using the Korn shell.
The script mpamddir is provided for mapping the C shell directory name to an AutoMount Daemon name.
MP_RESD: Determines whether or not the Partition Manager should connect to LoadLeveler to allocate nodes. Valid values are either yes or no, and there is no default. The value of this environment variable can be overridden using the -resd flag.
MP_RETRY: Determines the period of time (in seconds) between processor node allocation retries if there are not enough processor nodes immediately available to run a program. This is only valid if you are using LoadLeveler. Valid values are any integer greater than or equal to 0. The default is 0 (no retry). The value of this environment variable can be overridden using the -retry flag.
MP_RETRYCOUNT: The number of times (at the interval set by MP_RETRY) that the Partition Manager should attempt to allocate processor nodes. Valid values are any integer greater than or equal to 0. If not set, the default is 0. The value of this environment variable can be overridden using the -retrycount flag.
MP_MSG_API: Indicates to POE which message passing API is being used by the parallel tasks. You need to set this environment variable if a parallel task is using LAPI alone or in conjunction with MPI. You do not need to set it if a parallel task is using MPI only. The value of this environment variable can be overridden using the -msg_api flag.
MP_RMPOOL: Determines the name or number of the pool that should be used for non-specific node allocation. This environment variable/command-line flag only applies to LoadLeveler. Valid values are any identifying pool name or number. There is no default. The value of this environment variable can be overridden using the -rmpool flag.
MP_NODES: Specifies the number of physical nodes on which to run the parallel tasks. It may be used alone or in conjunction with MP_TASKS_PER_NODE and/or MP_PROCS, as described in Table 6. The value of this environment variable can be overridden using the -nodes flag.
MP_TASKS_PER_NODE: Specifies the number of tasks to be run on each of the physical nodes. It may be used in conjunction with MP_NODES and/or MP_PROCS, as described in Table 6, but may not be used alone. The value of this environment variable can be overridden using the -tasks_per_node flag.
MP_SAVEHOSTFILE: The name of an output host list file to be generated by the Partition Manager. Valid values are any relative or full path name. The value of this environment variable can be overridden using the -savehostfile flag.
MP_TIMEOUT: Controls the length of time POE waits before abandoning an attempt to connect to the remote nodes. The default is 150 seconds. MP_TIMEOUT also changes the length of time the communication subsystem will wait for a connection to be established during message passing initialization.
If the SP security method is "dce and compatibility", you may need to increase the MP_TIMEOUT value to allow POE to wait for the DCE servers to respond (or timeout if the servers are down).
MP_CKPTFILE: Defines the base name of the checkpoint file when checkpointing a program. See Checkpointing and restarting programs for more information.
MP_CKPTDIR: Defines the directory where the checkpoint file will reside when checkpointing a program. See Checkpointing and restarting programs for more information.

The following environment variables are associated with Job Specification.

MP_CMDFILE: Determines the name of a POE commands file used to load the nodes of your partition. If set, POE will read the commands file rather than STDIN. Valid values are any file specifier. The value of this environment variable can be overridden using the -cmdfile flag.
MP_LLFILE: Determines the name of a LoadLeveler job command file for node allocation. If you are performing specific node allocation, you can use a LoadLeveler job command file in conjunction with a host list file. If you do, the specific nodes listed in the host list file will be requested from LoadLeveler. Valid values are any relative or full path name. The value of this environment variable can be overridden using the -llfile environment variable.
MP_NEWJOB: Determines whether or not the Partition Manager maintains your partition for multiple job steps. Valid values are yes or no. If not set, the default is no. The value of this environment variable can be overridden using the -newjob flag.
MP_PGMMODEL: Determines the programming model you are using. Valid values are spmd or mpmd. If not set, the default is spmd. The value of this environment variable can be overridden using the -pgmmodel flag.
MP_SAVE_LLFILE: When using LoadLeveler for node allocation, the name of the output LoadLeveler job command file to be generated by the Partition Manager. The output LoadLeveler job command file will show the LoadLeveler settings that result from the POE environment variables and/or command-line options for the current invocation of POE. If you use the MP_SAVE_LLFILE environment variable for a batch job, or when the MP_LLFILE environment variable is set (indicating that a LoadLeveler job command file should participate in node allocation), POE will show a warning and will not save the output job command file. Valid values are any relative or full path name. The value of this environment variable can be overridden using the -save_llfile flag.

The following environment variables are associated with I/O Control.

MP_LABELIO

Determines whether or not output from the parallel tasks are labeled by task id. Valid values are yes or no. If not set, the default is no. The value of this environment variable can be overridden using the -labelio flag.

MP_STDINMODE

Determines the input mode - how STDIN is managed for the parallel tasks. Valid values are:

all: all tasks receive the same input data from STDIN.
none: no tasks receive input data from STDIN; STDIN will be used by the home node only.
n: STDIN is only sent to the task identified (n).

If not set, the default is all. The value of this environment variable can be overridden using the -stdinmode flag.

MP_HOLD_STDIN

Determines whether or not sending of STDIN from the home node to the remote nodes is deferred until the message passing partition has been established. Valid values are yes or no. If not set, the default is no.

MP_STDOUTMODE

Determines the output mode - how STDOUT is handled by the parallel tasks. Valid values are:

unordered: all tasks write output data to STDOUT asynchronously.
ordered: output data from each parallel task is written to its own buffer. Later, all buffers are flushed, in task order, to STDOUT.
a task id: only the task indicated writes output data to STDOUT.

If not set, the default is unordered. The value of this environment variable can be overridden using the -stdoutmode flag.

The following environment variables are associated with the generation of diagnostic information.

MP_INFOLEVEL: Determines the level of message reporting. Valid values are:

0: error
1: warning and error
2: informational, warning, and error
3: informational, warning, and error. Also reports diagnostic messages for use by the IBM Support Center.
4, 5, 6: Informational, warning, and error. Also reports high- and low-level diagnostic messages for use by the IBM Support Center.

If not set, the default is 1 (warning and error). The value of this environment variable can be overridden using the -infolevel or -ilevel flags.

MP_PMDLOG

Determines whether or not diagnostic messages should be logged to a file in /tmp on each of the remote nodes. Typically, this environment variable/command-line flag is only used under the direction of the IBM Support Center in resolving a PE-related problem. Valid values are yes or no. If not set, the default is no. The value of this environment variable can be overridden using the -pmdlog flag.

MP_DEBUG_INITIAL_STOP

Determines the initial breakpoint in the application where pdbx will get control. MP_DEBUG_INITIAL_STOP should be specified as file_name:line_number. The line_number is the number of the line within the source file file_name; where file_name has been compiled with -g. The line number has to be one that defines executable code. In general, this is a line of code for which the compiler generates machine level code. Another way to view this is that the line number is one for which debuggers will accept a breakpoint. Another valid string for MP_DEBUG_INITIAL_STOP would be the function_name of the desired initial stopping point in the debugger. If this variable is not specified, the default is to stop at the first executable source line in the main routine. This environment variable has no associated command-line flag.

MP_PMDSUFFIX

Determines a string to be appended to the Partition Manager daemon service, or executable (when using LoadLeveler).

The PMD service in /etc/services is named pmv3. By setting MP_PMDSUFFIX, you can append a string to pmv3. If MP_PMDSUFFIX is set to "abc", for example, the service requested in /etc/services is pmv3abc.

When using LoadLeveler, the string is appended to the partition manager daemon executable name, /etc/pmdv3. By setting MP_PMDSUFFIX, you can append a string to pmdv3. If MP_PMDSUFFIX is set to "abc", for example, the partition manager daemon that gets run on each node is /etc/pmdv3abc.

If the MP_PMD_VERSION environment variable (or -pmd_version flag) is set to a value of 2, the appropriate Partition Manager daemon service name and executable name is appended to pmv2 and pmdv2 respectively.

This permits testing of alternate versions of the Partition Manager daemon. Typically, this environment variable is used only under the direction of the IBM Support Center in resolving a PE-related problem. Valid values are any string. This environment variable has no associated command-line flag.

The following environment variables are associated with the Message Passing Interface.

MP_BUFFER_MEM

Changes the maximum size of memory used by the communication subsystem to buffer early arrivals. The default is 2.8 megabytes for IP and 64 megabytes for US. However, if checkpointing a program, for US the default will be 2.8 megabytes. If you are using this environment variable to change the maximum size of memory used by the communication subsystem while checkpointing a program, please be aware that the amount of space needed for the checkpointing files will be increased by the value of MP_BUFFER_MEM.

MP_CLOCK_SOURCE

Determines whether or not to use the SP switch clock as a time source. Valid values are AIX and switch. There is no default value. The value of this environment variable can be overridden using the -clock_source flag.

MP_CSS_INTERRUPT

Determines whether or not arriving message packets cause interrupts. This may provide better performance for certain applications. Valid values are yes and no. If not set, the default is no.

MP_EAGER_LIMIT

Changes the threshold value for message size, above which rendezvous protocol is used.

MP_HINTS_FILTERED

Determines whether MPI info objects reject hints (key/value pairs) which are not meaningful to the MPI implementation. In filtered mode, an MPI_INFO_SET call which provides a key/value pair that the implementation does not understand will behave as a no-op. A subsequent MPI_INFO_GET call will find that the hint does not exist in the info object.

In unfiltered mode, any key/value pair is stored and may be retrieved. Applications which wish to use MPI info objects to cache and retrieve key/value pairs other than those actually understood by the MPI implementation must use unfiltered mode. The option has no effect on the way MPI uses the hints it does understand. In unfiltered mode, there is no way for a program to discover which hints are valid to MPI and which are simply being carried as uninterpreted key/value pairs.

Providing an unrecognized hint is not an error in either mode.

Valid values for this environment variable are yes and no. If set to yes, unrecognized hints are be filtered. If set to no, they will not. If this environment variable is not set, the default is yes. The value of this environment variable can be overridden using the -hints_filtered command-line flag.

MP_INTRDELAY

Allows user programs to tune the interruptdelay parameter without having to recompile existing applications.

MP_MAX_TYPEDEPTH

Changes the maximum depth of user-defined message data types.

MP_IONODEFILE

The name of a parallel I/O node file -- a text file that lists the nodes that should be handling parallel I/O. This enables you to limit the number of nodes that participate in parallel I/O, guarantee that all I/O operations are performed on the same node, and so on. Valid values are any relative or full path name. If not specified, all nodes will participate in parallel I/O operations. The value of this environment variable can be overridden using the -ionodefile command-line flag.

MP_SHARED_MEMORY

Determines whether or not tasks running on the same node should use shared memory (instead of the SP switch) for message passing. Valid values are yes and no. If not set, the default is no. The value of this environment variable can be overridden using the -shared_memory flag.

MP_SYNC_ON_CONNECT

Determines whether or not the internal synchronization of MPI initialization is disabled, thereby reducing the amount of network traffic. Valid values are yes and no. If not set, the default is yes.

MP_USE_FLOW_CONTROL

Applies flow control to MPI programs so that a sender can't outpace a receiver.

MP_THREAD_STACKSIZE

Determines the additional stacksize allocated for user programs executing on an MPI service thread. If you allocate insufficient space, the program may encounter a SIGSEGV exception.

MP_SINGLE_THREAD

Avoids mutex lock overheads in a single threaded program. This is an optimization flag, with values of no and yes. The default value is no, which means multiple user message passing threads are assumed.

Note:: MPI-IO cannot be used if this is set to YES. Results are undefined if this is YES, with multiple message passing threads in use.

MP_WAIT_MODE

Determines how a thread or task behaves when it discovers it is blocked, waiting for a message to arrive. Values are poll, yield, sleep, and nopoll. The default mode for the signal handling library is poll for US, and sleep for IP (except on SMP nodes). The default for IP on an SMP node is poll if the number of tasks (for this job) on the node does not exceed the number of processors on the node. If the number of tasks does exceed the number of processors, the default is sleep.

MP_POLLING_INTERVAL

Defines the polling interval in microseconds. The maximum interval is approximately 2 billion microseconds (2000 seconds). The default is 180,000 microseconds for IP, and 400,000 microseconds for US.

MP_RETRANSMIT_INTERVAL

MP_RETRANSMIT_INTERVAL=nnnnn and its command line equivalent, -retransmit_interval=nnnnn, control how often the communication subsystem library checks to see if it should retransmit packets that have not been acknowledged. The value nnnnn is the number of polling loops between checks. The acceptable range is 1000 to 400000. The default is 10,000 for UDP and 400,000 for User Space.

MP_IO_BUFFER_SIZE

Indicates the default size of the data buffer used by MPI-IO agents. For example:

export MP_IO_BUFFER_SIZE=16M

sets the default size of the MPI-IO data buffer to 16MB. The default value of the environment variable is the number of bytes corresponding to 16 file blocks. This value depends on the block size associated with the file system storing the file. Valid values are any positive size up to 128MB. The size can be expressed as a number of bytes, as a number of KB (1024 bytes), using the letter k as a suffix, or as a number of MB (1024 * 1024 bytes), using the letter m as a suffix.

MP_IO_ERRLOG

Indicates whether to turn on error logging for I/O operations. For example:

export MP_IO_ERRLOG=yes

turns on error logging. When an error occurs, a line of information will be logged into file /tmp/mpi_io_errdump.app_name.userid.taskid, recording the time the error occurs, the POSIX file system call involved, the file descriptor, and the returned error number.

The following are corefile generation environment variables:

MP_COREDIR: Creates a separate directory for each task's core file. The value of this environment variable can be overridden using the -coredir flag. A value of "none" signifies to bypass creating a new directory resulting in core files written to /tmp.
MP_COREFILE_FORMAT: Determines the format of corefiles generated when processes terminate abnormally. If not set, POE will generate standard AIX corefiles. If set to the string "STDERR", output will go to standard error. If set to any other string, POE will generate a lightweight corefile (conforming to the Parallel Tool consortium's Standardized Lightweight Corefile Format) for each process in your partition. The string you specify is the name you want to assign to each lightweight corefile. By default, these lightweight corefiles will be saved to subdirectories prefixed by the string coredir and suffixed by the task id (as in coredir.0, coredir.1, and so on). You can specify a prefix other than the default coredir by setting the MP_COREDIR environment variable. The value of this environment variable can be overridden using the -corefile_format flag.

The following are miscellaneous environment variables:

MP_EUIDEVELOP: Determines whether or not the message passing interface performs more detailed checking during execution. This additional checking is intended for developing applications, and can significantly slow performance. Valid values are yes or no, deb (for "debug"), nor (for "normal"), and min (for "minimum"). The debug and min values are used to enable and disable parameter checking. If not set, the default is no. The value of this environment variable can be overridden using the -euidevelop flag.
MP_FENCE: Determines a fence_string to be used for separating options you want parsed by POE from those you do not. Valid values are any string, and there is no default. Once set, you can then use the fence_string followed by additional_options on the poe command line. The additional_options will not be parsed by POE. This environment variable has no associated command-line flag.
MP_NOARGLIST: Determines whether or not POE ignores the argument list. Valid values are yes and no. If set to yes, POE will not attempt to remove POE command-line flags before passing the argument list to the user's program. This environment variable has no associated command-line flag.
MP_PMLIGHTS: Indicates the number of lights displayed per row on the Program Marker Array.
MP_PRIORITY: Determines a dispatch priority adjustment class for execution. See IBM Parallel Environment for AIX: Installation for more information on dispatch priority classes. Valid values are any of the dispatch priority classes set up by the system administrator in the file /etc/poe.priority. This environment variable has no associated command-line flag.
MP_USRPORT: Indicates the port id used by the Partition Manager to connect to the Program Marker Array. By default, the Partition Manager connects to the Array using a socket assigned to port 9999. If you get an error message indicating that the port is in use, specify a different port. Standard TCP/IP practice suggests using ports greater than 5000 and less than 10000.

EXAMPLES

Assume the MP_PGMMODEL environment variable is set to spmd, and MP_PROCS is set to 6. To load and execute the SPMD program sample on the six remote nodes of your partition, enter:
```
 poe sample
 
```
Assume you have an MPMD application consisting of two programs - master and workers. These programs are designed to run together and communicate via calls to message passing subroutines. The program master is designed to run on one processor node. The workers program is designed to run as separate tasks on any number of other nodes. The MP_PGMMODEL environment variable is set to mpmd, and MP_PROCS is set to 6. To individually load the six remote nodes with your MPMD application, enter:
```
 poe
 
```
Once the partition is established, the poe command responds with the prompt:
```
 0:host1_name>
 
```
To load the master program as task 0 on host1_name, enter:
```
 master
 
```
The poe command responds with a prompt for the next node to load. When you have loaded the last node of your partition, the poe command displays the message Partition loaded... and begins execution.
Assume you want to run three SPMD programs - setup, computation, and cleanup - as job steps on the same partition of nodes. The MP_PGMMODEL environment variable is set to spmd, and MP_NEWJOB is set to yes. You enter:
```
 poe
 
```
Once the partition is established, the poe command responds with the prompt:
```
 Enter program name (or quit):
 
```
To load the program setup, enter:
```
 setup
 
```
The program setup executes on all nodes of your partition. When execution completes, the poe command again prompts you for a program name. Enter the program names in turn. To release the partition, enter:
```
 quit
 
```
To check the process status (using the non-parallel command ps) for all remote nodes in your partition, enter:
```
 poe ps
 
```

FILES

host.list (Default host list file)

RELATED INFORMATION

Commands: mpcc(1), mpcc_r(1), mpCC(1), mpCC_r(1), mpxlf(1), mpxlf_r(1), pdbx(1), pmarray(1), xprofiler(1)

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