NOTE: This man page is for POE version 3.1

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}]
   [{-samplefreq | -sfreq} samp_int]
   [{-tbuffsize | -tbsize} buffer_size]
   [{-tbuffwrap | -tbwrap} {yes | no}]
   [-tmpdir temp_trace_directory]
   [{-tracedir | -tdir} final_trace_directory]
   [{-tracefile | -tfile} trace_file_name]
   [{-tracelevel | -tlevel} level_int]
   [{-ttempsize | -ttsize} temp_file_size]
   [{-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]
   [-coredir directory_prefix_string]
   [-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 Parallel Trace Collection flags override the associated
   environment variables.
 
   -samplefreq or  -sfreq
                       MP_SAMPLEFREQ
   -tbuffsize or -tbsize
                       MP_TBUFFSIZE
   -tbuffwrap or -tbwrap
                       MP_TBUFFWRAP
   -tmpdir             MP_TMPDIR
   -tracedir or -tdir  MP_TRACEDIR
   -tracefile or -tfile
                       MP_TRACEFILE
   -tracelevel or -tlevel
                       MP_TRACELEVEL
   -ttempsize or -ttsize
                       MP_TTEMPSIZE
 
   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
 
   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:
 
   o   load and execute an SPMD program on all nodes of your partition.
 
   o   individually load the nodes of your partition with an MPMD job.
 
   o   load and execute a series of SPMD and MPMD programs, in individual
       job steps, on the same partition.
 
   o   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:
 
   o   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.
 
   o   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.
 
   o   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.
 
   o   Parallel trace collection. The environment variables and flags in
       this category determine if and how execution traces are collected.
       They determine which types of traces are collected, and how trace
       storage is handled.
 
   o   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.
 
   o   Message Passing Interface. The environment variables and flags in
       this category enable you to specify values for tuning message
       passing applications.
 
   o   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).
 
   o   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.
                       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. 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), and css0 (for
                       the SP system's high performance switch feature).
 
   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 the libraries are moved. 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 or pedb debuggers. 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. 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, 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_CHECKFILE        Defines the base name of the checkpoint file when
                       checkpointing or restarting a program.
 
   MP_CHECKDIR         Defines the directory where the checkpoint file
                       will reside when checkpointing or restarting a
                       program.
 
   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 Parallel Trace
   Collection.
 
   MP_SAMPLEFREQ       Determines the interval (in milliseconds) at which
                       AIX kernel statistics are sampled when executing a
                       program with tracing on. Valid values are any
                       integer greater than or equal to 0. If not set,
                       the default is 10. The value of this environment
                       variable can be overridden using the -samplefreq
                       or -sfreq flags.
 
   MP_TBUFFSIZE        Determines the size (in bytes) of the buffer used
                       when generating trace files. This may be specified
                       as nnnK or nnnM. If not set, the default is 5M.
                       The value of this environment variable can be
                       overridden using the -tbuffsize or -tbsize flags.
 
   MP_TBUFFWRAP        Determines that a wraparound storage approach for
                       trace records should be used instead of the
                       default three-tiered approach. With this approach,
                       the system keeps overwriting the buffer instead of
                       flushing it to a temp file.  Valid values are
                       either yes or no. If not set, the default is no.
                       The value of this environment variable can be
                       overridden using the -tbuffwrap or -tbwrap flags.
 
   MP_TMPDIR           The temporary directory to which output trace
                       files are written. Valid values are any path
                       specifier. If not set, the default is
                       /tmp/username. The value of this environment
                       variable can be overridden using the -tmpdir flag.
 
   MP_TRACEDIR         Determines the directory to which the final
                       integrated trace file is built. Valid values are
                       any path specifier. If not set, the default is the
                       current directory. The value of this environment
                       variable can be overridden using the -tracedir or
                       -tdir flags.
 
   MP_TRACEFILE        Determines the name of the output trace file
                       created when executing a program with tracing on.
                       Valid values are any file specifier. If not set,
                       the default is the name of the program with the
                       suffix .trc added. The value of this environment
                       variable can be overridden using the -tracefile
                       and -tfile flags.
 
   MP_TRACELEVEL       Determines the level of parallel tracing that
                       should be generated during the execution of a
                       program.  Valid values are:
 
                       0  no trace records
 
                       1  Application Markers
 
                       2  AIX Kernel Statistic and Application Markers
 
                       3  Message Passing, Collective Communication, and
                          Application Markers
 
                       9  all trace records
 
                       If not set, the default is 0 (no trace records).
                       The value of this environment variable can be
                       overridden using the -tracelevel or -tlevel flags.
 
   MP_TTEMPSIZE        Determines the size (in bytes) of the temp file
                       used when generating trace files. This may be
                       specified as nnnM or nnnG. If not set, the default
                       is 10M. The value of this environment variable can
                       be overridden using the -ttempsize or -ttsize
                       flags.
 
   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_LOG        Determines the level of diagnostic messages
                       written to $MP_tmp/dbelog.pid.taskid. Typically,
                       this environment variable/command-line flag is
                       only used under the direction of the IBM Support
                       Center in resolving a PE-related problem. This
                       environment variable has no associated
                       command-line flag.
 
   MP_DEBUG_INITIAL_STOP
                       Determines the initial breakpoint in the
                       application where pdbx or pedb 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 yes and
                       no. 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 delay 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, and sleep. 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.
 
   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.
 
   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
                       start and stop 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
 
 
   1.  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
 
 
   2.  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.
 
   3.  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
 
 
   4.  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), pedb(1), pmarray(1), xprofiler(1)