-
Mark Grondona authoredMark Grondona authored
srun.1 25.39 KiB
\." $Id$
.\"
.TH SRUN "1" "September 2003" "srun 0.2" "slurm components"
.SH "NAME"
srun \- run parallel jobs
.SH SYNOPSIS
.B srun
[\fIOPTIONS\fR...] \fIexecutable \fR[\fIargs\fR...]
.br
.B srun
\-\-batch [\fIOPTIONS\fR...] job_script
.br
.B srun
\-\-allocate [\fIOPTIONS\fR...] [job_script]
.br
.B srun
\-\-attach=jobid
.SH DESCRIPTION
Allocate resources and optionally initiate parallel jobs on
clusters managed by SLURM.
.TP
parallel run options
.TP
\fB\-n\fR, \fB\-\-nprocs\fR=\fInprocs\fR
Specify the number of processes to run. Request that \fBsrun\fR
allocate \fInprocs\fR processes. Specification of the number of
processes per node may be achieved with the \fB\-c\fR and \fB\-N\fR
options. The default is one process per node unless \fB\-c\fR
explicitly specifies otherwise.
.TP
\fB\-c\fR, \fB\-\-cpus\-per\-task\fR=\fIncpus\fR
Request that \fIncpus\fR be allocated \fBper process\fR. This may be
useful if the job is multithreaded and requires more than one cpu
per task for optimal performance. The default is one cpu per process.
.TP
\fB\-N\fR, \fB\-\-nodes\fR=\fInnodes\fR
Request that \fInnodes\fR nodes be allocated to this job. \fInnodes\fR
may be either a specific number or a minimum and maximum node count
separated by a hyphen (e.g. "\-\-nodes=2\-4"). The partition's node
limits supersede those of the job. If a job's node limits are completely
outside of the range permitted for it's associated partition, the job
will be left in a PENDING state. Note that the environment
variable \fBSLURM_NNODES\fR will be set to the count of nodes actually
allocated to the job. See the \fBENVIRONMENT VARIABLES \fR section
for more information. The default
is to allocate one cpu per process, such that nodes with one cpu will
run one process, nodes with 2 cpus will be allocated 2 processes, etc.
The distribution of processes across nodes may be controlled using this
option along with the \fB\-n\fR and \fB\-c\fR options.
.TP
\fB\-r\fR, \fB\-\-relative\fR=\fIn\fR
Run a job step relative to node \fIn\fR of the current allocation.
This option may be used to spread several job steps out among the
nodes of the current job. If \fB-r\fR is used, the current job
step will begin at node \fIn\fR of the allocated nodelist, where
the first node is considered node 0. The \fB\-r\fR option is not
permitted along with \fB\-w\fR or \fB\-x\fR, and will be silently
ignored when not running within a prior allocation (i.e. when
SLURM_JOBID is not set). The default for \fIn\fR is 0. If the
value of \fB\-\-nodes\fR exceeds the number of nodes identified
with the \fB\-\-relative\fR option, a warning message will be
printed and the \fB\-\-relative\fR option will take precedence.
.TP
\fB\-p\fR, \fB\-\-partition\fR=\fIpartition\fR
Request resources from partition "\fIpartition\fR." Partitions
are created by the slurm administrator.
.TP
\fB\-t\fR, \fB\-\-time\fR=\fIminutes\fR
Establish a time limit to terminate the job after the specified number of
minutes. If the job's time limit exceed's the partition's time limit, the job will be left in a PENDING state. The default value is the partition's
time limit. When the time limit is reached, the job's processes are sent
SIGTERM followed by SIGKILL. The interval between signals is specified by
the SLURM configuration parameter \fBKillWait\fR.
.TP
\fB\-\-chdir\fR=\fIpath\fR
have the remote processes do a chdir to \fIpath\fR before beginning
execution. The default is to chdir to the current working directory
of the \fBsrun\fR process.
.TP
\fB\-I\fR, \fB\-\-immediate\fR
exit if resources are not immediately
available. By default, \fB\-\-immediate\fR is off, and
.B srun
will block until resources become available.
.TP
\fB\-k\fR, \fB\-\-no-kill\fR
Do not automatically terminate a job of one of the nodes it has been allocated
fails. The job will assume all responsibilities for fault-tolerance. The
default action is to terminate the job upon node failure.
.TP
\fB\-s\fR, \fB\-\-share\fR
The job can share nodes with other running jobs. This may result in faster job
initiation and higher system utilization, but lower application performance.
.TP
\fB\-O\fR, \fB\-\-overcommit\fR
overcommit resources. Normally,
.B srun
will not allocate more than one process per cpu. By specifying
\fB\-\-overcommit\fR you are explicitly allowing more than one process
per cpu. However no more than \fBMAX_TASKS_PER_NODE\fR tasks are
permitted to execute per node.
./"NOTE: Do not document feature until user release mechanism is available.
./".TP
./"-H, --hold
./"Specify the job is to be submitted in a held state (priority of zero).
./"A held job can now be released using scontrol to reset its priority.
.TP
\fB\-T\fR, \fB\-\-threads\fR=\fInthreads\fR
Request that
.B srun
use \fInthreads\fR to initiate and control the parallel job. The
default value is the smaller of 10 or the number of nodes allocated.
.TP
\fB\-l\fR, \fB\-\-label\fR
prepend task number to lines of stdout/err. Normally, stdout and stderr
from remote tasks is line-buffered directly to the stdout and stderr of
.B srun
The \fB\-\-label\fR option will prepend lines of output with the remote
task id.
.TP
\fB-u\fR, \fB\-\-unbuffered\fR
do not line buffer stdout from remote tasks. This option cannot be used
with \fI\-\-label\fR.
.TP
\fB\-m\fR, \fB\-\-distribution\fR=(\fIblock\fR|\fIcyclic\fR)
Specify an alternate distribution method for remote processes.
.RS
.TP
.B block
The block method of distribution will allocate processes in-order to
the cpus on a node. This is the default behavior if the number of tasks
exceeds the number of nodes requested.
.TP
.B cyclic
The cyclic method distributes processes in a round-robin fashion across
the allocated nodes. That is, process 1 will be allocated to the first
node, process 2 to the second, and so on. This is the default behavior
if the number of tasks is no larger than the number of nodes requested.
.RE.TP
\fB\-J\fR, \fB\-\-job\-name\fR=\fIjobname\fR
Specify a name for the job. The specified name will appear along with
the job id number when querying running jobs on the system. The default
is the supplied \fBexecutable\fR program's name.
.TP
\fB--jobid\fR=\fIid\fR
Initiate a job step under an already allocated job with job id \fIid\fR.
Using this option will cause \fBsrun\fR to behave exactly as if the
SLURM_JOBID environment variable was set.
.TP
\fB\-o\fR, \fB\-\-output\fR=\fImode\fR
Specify the mode for stdout redirection. By default,
.B srun
collects stdout from all tasks and line buffers this output to
the attached terminal. With \fB\-\-output\fR stdout may be redirected
to a file, to one file per task, or to /dev/null. See section
\fBIO Redirection\fR below for the various forms of \fImode\fR.
.TP
\fB\-i\fR, \fB\-\-input\fR=\fImode\fR
Specify how stdin is to redirected. By default,
.B srun
redirects stdin from the terminal all tasks. See \fBIO Redirection\fR
below for more options.
.TP
\fB\-e\fR, \fB\-\-error\fR=\fImode\fR
Specify how stderr is to be redirected. By default,
.B srun
redirects stderr to the same file as stdout, if one is specified. The
\fB\-\-error\fR option is provided to allow stdout and stderr to be
redirected to different locations.
See \fBIO Redirection\fR below for more options.
.TP
\fB\-b\fR, \fB\-\-batch\fR
Submit in "batch mode." \fBsrun\fR will make a copy of the \fIexecutable\fR
file (a script) and submit the request for execution when resouces are
available. \fBsrun\fR will terminate after the request has been submitted.
The \fIexecutable\fR file will run on the first node allocated to the
job and must contain \fBsrun\fR commands to initiate parallel tasks.
stdin will be redirected from /dev/null, stdout and stderr will be
redirected to a file (default is \fIjobname\fR.out or \fIjobid\fR.out in
current working directory, see \fB\-o\fR for other IO options).
\fIexecutable\fR must be specified using either a fully qualified
pathname or its pathname will be relative to the current working directory.
The search path will not be used to locate the file. \fIexecutable\fR
will be interpreted by the user's default shell unless the file begins
with "#!" followed by the fully qualified pathname of a valid shell.
.TP
\fB\-v\fR, \fB\-\-verbose\fR
verbose operation. Multiple \fB-v\fR's will further increase the verbosity of
.B srun.
.TP
\fB\-d\fR, \fB\-\-slurmd-debug\fR=\fIlevel\fR
Specify a debug level for slurmd(8). \fIlevel\fR may be an integer value
between 0 [quiet, only errors are displayed] and 5 [insanely verbose
operation]. The slurmd debug information is copied onto the stderr of
the job.
.TP
\fB\-W\fR, \fB\-\-wait\fR=\fIseconds\fR
Specify how long to wait after the first task terminates before terminating
all remaining tasks. The default value is unlimited. This can be useful to
insure that a job is terminated in a timely fashion in the event that one
or more tasks terminate prematurely.
.PP
Allocate options:
.TP
\fB\-A\fR, \fB\-\-allocate\fR
allocate resources and spawn a shell. When \fB\-\-allocate\fR is specified to
.B srun
, no remote tasks are started. Instead a subshell is started that has accessto the allocated resources. Multiple jobs can then be run on the same cpus
from within this subshell. See \fBAllocate Mode\fR below.
.PP
Attach to running job:
.TP
\fB\-a\fR, \fB\-\-attach\fR=\fIid\fR
This option will attach
.B srun
to a running job with job id = \fIid\fR. Provided that the calling user
has access to that running job, stdout and stderr will be redirected to the
current session and signals received by
.B srun
will be forwarded to the remote processes.
.TP
\fB\-j\fR, \fB\-\-join\fR
Join with running job. This will duplicate stdout/stderr to the calling
\fBsrun\fR. stdin and signals will not be propagated to the job.
\fB\-\-join\fR is only allowed with \fB\-\-attach\fR.
.TP
\fB\-s\fR, \fB\-\-steal\fR
Steal the connection to the running job. This will close any open
sessions with the specified job and allow stdin and signals to be propagated.
\fB\-\-steal\fR is only allowed with \fB\-\-attach\fR.
.PP
Constraint Options. The following options all put constraints on the nodes
that may be considered for the job:
.TP
\fB\-\-mincpus\fR=\fIn\fR
Specify minimum number of cpus per node.
.TP
\fB\-\-mem\fR=\fIMB\fR
Specify a minimum amount of real memory.
.TP
\fB\-\-vmem\fR=\fIMB\fR
Specify a minimum amount of virtual memory.
.TP
\fB\-\-tmp\fR=\fIMB\fR
Specify a minimum amount of temporary disk space.
.TP
\fB\-C\fR, \fB\-\-constraint\fR=\fIlist\fR
Specify a list of constraints.
The constraints are features that have been assigned to the nodes by
the slurm administrator.
The \fIlist\fR of constraints may include multiple features separated
by commas, in which case all nodes must have all listed features
(i.e. the features are ANDed together).
Alternately the features may be separated by a vertical bar, '|',
in which case all nodes have must have at least one of the listed
features (i.e. the features are ORed together).
If no nodes have the requested features, then the job will be rejected
by the slurm job manager.
.TP
\fB\-\-contiguous\fR
Demand a contiguous range of nodes. The default is "yes". Specify
--contiguous=no if a contiguous range of nodes is not a constraint.
.TP
\fB\-w\fR, \fB\-\-nodelist\fR=\fIhost1,host2,...\fR or \fIfilename\fR
Request a specific list of hosts. The job will contain \fIat least\fR
these hosts. The list may be specified as a comma-separated list of
hosts, a range of hosts (host[1-5,7,...] for example), or a filename.
The host list will be assumed to be a filename if it contains a "/"
character.
.TP
\fB\-x\fR, \fB\-\-exclude\fR=\fIhost1,host2,...\fR or \fIfilename\fR
Request that a specific list of hosts not be included in the resources
allocated to this job. The host list will be assumed to be a filename
if it contains a "/"character.
.PP
Help options.TP
-?, \fB\-\-help\fR
Show this help message
.TP
\fB\-\-usage\fR
Display brief usage message
.PP
Other options
.TP
\fB\-V\fR, \fB\-\-version\fR
output version information and exit
.PP
Unless the \fB\-a\fR (\fB\-\-attach\fR) or \fB-A\fR (\fB\-\-allocate\fR)
options are specified (see \fBAllocate mode\fR and \fBAttaching to jobs\fR
below),
.B srun
will submit the job request to the slurm job controller, then initiate all
processes on the remote nodes. If the request cannot be met immediately,
.B srun
will block until the resources are free to run the job. If the
\fB\-I\fR (\fB\-\-immediate\fR) option is specified
.B srun
will terminate if resources are not immediately available.
.PP
When initiating remote processes
.B srun
will propagate the current working directory, unless
\fB\-\-chdir\fR=\fIpath\fR is specified, in which case \fIpath\fR will
become the working directory for the remote processes.
.PP
The \fB-n\fB, \fB-c\fR, and \fB-N\fR options control how CPUs and
nodes will be allocated to the job. When specifying only the number
of processes to run with \fB-n\fR, a default of one CPU per process
is allocated. By specifying the number of CPUs required per task (\fB-c\fR),
more than one CPU may be allocated per process. If the number of nodes
is specified with \fB-N\fR,
.B srun
will attempt to allocate \fIat least\fR the number of nodes specified.
.PP
Combinations of the above three options may be used to change how
processes are distributed across nodes and cpus. For instance, by specifying
both the number of processes and number of nodes on which to run, the
number of processes per node is implied. However, if the number of CPUs
per process is more important then number of processes (\fB-n\fR) and the
number of CPUs per process (\fB-c\fR) should be specified.
.PP
.B srun
will refuse to allocate more than one process per CPU unless
\fB\-\-overcommit\fR (\fB\-O\fR) is also specified.
.PP
.B srun
will attempt to meet the above specifications "at a minimum." That is,
if 16 nodes are requested for 32 processes, and some nodes do not have
2 CPUs, the allocation of nodes will be increased in order to meet the
demand for CPUs. In other words, a \fIminimum\fR of 16 nodes are being
requested. However, if 16 nodes are requested for 15 processes,
.B srun
will consider this an error, as 15 processes cannot run across 16 nodes.
.PP
.B "IO Redirection"
.PP
By default stdout and stderr will be redirected from all tasks to the
stdout and stderr of
.B srun
, and stdin will be redirected from the standard input of
.B srun
to all remote tasks. This behavior may be changed with the
\fB\-\-output\fR, \fB\-\-error\fR, and \fB\-\-input\fR
(\fB\-o\fR, \fB\-e\fR, \fB\-i\fR) options. Valid format specifications
for these options are.TP 10
\fBall\fR
stdout stderr is redirected from all tasks to srun.
stdin is broadcast to all remote tasks.
(This is the default behavior)
.TP
\fBnone\fR
stdout and stderr is not received from any task.
stdin is not sent to any task (stdin is closed).
.TP
\fItaskid\fR
stdout and/or stderr are redirected from only the task with relative
id equal to \fItaskid\fR, where 0 <= \fItaskid\fR <= \fIntasks\fR,
where \fIntasks\fR is the total number of tasks in the current job step.
stdin is redirected from the stdin of
.B srun
to this same task.
.TP
\fIfilename\fR
.B srun
will redirect stdout and/or stderr to the named file from all tasks.
stdin will be redirected from the named file and broadcast to all
tasks in the job. If the job is submitted in batch mode using the
.B -b
or
.B --batch
option, \fIfilename\fR refers to a path on each of the nodes on which
the job runs. Otherwise \fIfilename\fR refers to a path on the host
that runs \fBsrun\fR. Depending on the cluster's file system layout,
this may result in the output appearing in different places depending
on whether the job is run in batch mode.
.TP
format string
.B srun
allows for a format string to be used to generate the named IO file
described above. The following list of format specifiers may be
used in the format string to generate a filename that will be
unique to a given jobid, stepid, node, or task. In each case,
the appropriate number of files are opened and associated with
the corresponding tasks.
.RS 10
.TP
%J
jobid.stepid of the running job. (e.g. "128.0")
.TP
%j
jobid of the running job.
.TP
%s
stepid of the running job.
.TP
%N
short hostname. This will create a separate IO file per node.
.TP
%n
Node identifier relative to current job (e.g. "0" is the first node of
the running job) This will create a separate IO file per node.
.TP
%t
task identifier (rank) relative to current job. This will create a
separate IO file per task.
.PP
A number placed between the percent character and format specifier may be
used to zero-pad the result in the IO filename. This number is ignored if
the format specifier corresponds to non-numeric data (%N for example).
Some examples of how the format string may be used for a 4 task job step
with a Job ID of 128 and step id of 0 are included below:
.TP 15
job%J.outjob128.0.out
.TP
job%4j.out
job0128.out
.TP
job%j-%2t.out
job128-00.out, job128-01.out, ...
.PP
.RS -10
.PP
.B "Allocate Mode"
.PP
When the allocate option is specified (\fB\-A\fR, \fB\-\-allocate\fR)
\fBsrun\fR will not initiate any remote processes after acquiring
resources. Instead, \fBsrun\fR will spawn a subshell which has access
to the acquired resources. Subsequent instances of \fBsrun\fR from within
this subshell will then run on these resources.
.PP
If the name of a script is specified on the
commandline with \fB\-\-allocate\fR, the spawned shell will run the
specified script. Resources allocated in this way will only be freed
when the subshell terminates.
.PP
.B "Attaching to a running job"
.PP
Use of the \fB-a\fR \fIjobid\fR (or \fB\-\-attach\fR) option allows
\fBsrun\fR to reattach to a running job, receiving stdout and stderr
from the job and forwarding signals to the job, just as if the current
session of \fBsrun\fR had started the job. (stdin, however, cannot
be forwarded to the job).
.PP
There are two ways to reattach to a running job. The default method
is to attach to the current job read-only. In this case,
stdout and stderr are duplicated to the attaching \fBsrun\fR, but
signals are not forwarded to the remote processes (A single
Ctrl-C will detach this read-only \fBsrun\fR from the job). If
the \fB-j\fR (\fB\-\-join\fR) option is is also specified,
\fBsrun\fR "joins" the running job, and is able to forward signals
and acts for the most part much like the \fBsrun\fR process that
initiated the job.
.PP
Attaching to running batch jobs is also supported, if the batch
job is being managed by SLURM (That is, a script submitted with
\fBsrun \-b\fR). The stdout and stderr from the \fIbatch script\fR
will then be copied to the attaching \fBsrun\fR, and if \fB-j\fR
is also specified, signals will be sent to the batch script.
This feature provides a good method for determining the status
of a running \fBsrun\fR within a batch script. For example,
consider attaching to a running batch job with jobid 483:
.br
.br
> srun --join --attach 483
.br
.br
After pressing Ctrl-C twice within one second, SIGINT is forwarded
to the batch job script, and the running srun reports its status:
.br
.br
attach[483]: interrupt (one more within 1 sec to abort)
.br
attach[483]: sending Ctrl-C to job
.br
srun: interrupt (one more within 1 sec to abort)
.br
srun: task[0-15]: running
.br
.br
showing that all 16 tasks in the current job step are running.
.PP
Node and CPU selection options do not make sense when specifying
\fB\-\-attach\fR, and it is an error to use \fB-n\fR, \fB-c\fR,
or \fB-N\fR in attach mode.
.PP
.SH "ENVIRONMENT VARIABLES"
.PP
Some
.B srun
options may be set via environment variables. These environment
variables, along with their corresponding options, are listed below.
(Note: commandline options will always override these settings)
.TP 20
SLURM_CPUS_PER_TASK
\fB\-c, \-\-ncpus\-per\-task\fR=\fIn\fR
.TP
SLURM_DEBUG
\fB\-v, \-\-verbose\fR
.TP
SLURMD_DEBUG
\fB\-d, \-\-slurmd-debug\fR
.TP
SLURM_DISTRIBUTION
\fB\-m, \-\-distribution\fR=(\fIblock|cyclic\fR)
.TP
SLURM_LABELIO
\fB-l, --label\fR
.TP
SLURM_NNODES
\fB\-N, \-\-nodes\fR=(\fIn|min-max\fR)
.TP
SLURM_NPROCS
\fB\-n, \-\-nprocs\fR=\fIn\fR
.TP
SLURM_OVERCOMMIT
\fB\-o, \-\-overcommit\fR
.TP
SLURM_PARTITION
\fB\-p, --partition\fR=\fIpartition\fR
.TP
SLURM_STDERRMODE
\fB\-e, \-\-error\fR=\fImode\fR
.TP
SLURM_STDINMODE
\fB\-i, \-\-input\fR=\fImode\fR
.TP
SLURM_STDOUTMODE
\fB\-o, \-\-output\fR=\fImode\fR
.TP
SLURM_TIMELIMIT
\fB\-t, \-\-time\fR=\fIminutes\fR
.TP
SLURM_WAIT
\fB\-W, \-\-wait\fR=\fIseconds\fR
.PP
Additionally,
.B srun
will set some environment variables in the environment of the
executing tasks on the remote compute nodes. These environment variables
are:
.TP 20
SLURM_JOBID
job id of the executing job.
.TP
SLURM_PROCID
the MPI rank (or relative process ID) of the current process
.TP
SLURM_NODEIDThe relative node ID of the current node
.TP
SLURM_NPROCS
total number of processes in the current job
.TP
SLURM_NODELIST
list of nodes that the slurm job is executing on.
.SH "SIGNALS AND ESCAPE SEQUENCES"
Signals sent to the \fBsrun\fR command are automatically forwarded to
the tasks it is controlling with a few exceptions. The escape sequence
\fB<control-c>\fR will report the state of all tasks associated with
the \fBsrun\fR command. If \fB<control-c>\fR is entered twice within
one second, then the associated SIGINT signal will be sent to all tasks.
If a third \fB<control-c>\fR is received, the job will be forcefully
terminated without waiting for remote tasks to exit.
The escape sequence \fB<control-z>\fR is presently ignored. Our intent
is for this put the \fBsrun\fR command into a mode where various special
actions may be invoked.
.SH "MPI SUPPORT"
On computers with a Quadrics interconnect, \fBsrun\fR directly supports
the Quadrics version of MPI without modification. Applications build
using the Quadrics MPI library will communicate directly over the
Quadrics interconnect without any special \fBsrun\fR options.
Users may also use MPICH on any computer where that is available.
The \fBmpirun\fR command may need to be provided with information
on its command line identifying the resources to be used. The
installer of the MPICH software may configure it to perform these
steps automatically. At worst, you must specify two parameters:
.TP
\fB\-np SLURM_NPROCS\fR
number of processors to run on
.TP
\fB\-machinefile <machinefile>\fR
list of computers on which to execute. This list can be constructed
executing the command \fBsrun /bin/hostname\fR and writing its standard
output to the desired file. Execute \fBmpirun \-\-help\fR for more options.
.SH "EXAMPLES"
This simple example demonstrates the execution of the command \fBhostname\fR
in eight tasks. At least eight processors will be allocated to the job
(the same as the task count) on however many nodes are required to satisfy
the request. The output of each task will be proceeded with its task number.
(The machine "dev" in the example below has a total of two CPUs per node)
.nf
> srun \-n8 \-l hostname
0: dev0
1: dev0
2: dev1
3: dev1
4: dev2
5: dev2
6: dev3
7: dev3
.fi
.PP
This example demonstrates how one might submit a script for later
execution (batch mode). The script will be initiated when resources
are available and no higher priority job is pending for the same
partition. The script will execute on 4 nodes with one task per node
implicit. Note that the script executes on one node. For the script
to utilize all allocated nodes, it must execute the \fBsrun\fR command
or an MPI program.
.nf
> cat test.sh
#!/bin/sh
date
srun \-l hostname
> srun \-N4 \-b test.sh
srun: jobid 42 submitted
.fi
.PP
The output of test.sh would be found in the default output file
"slurm-42.out."
.PP
The srun \fB-r\fR option is used within a job script
to run two job steps on disjoint nodes in the following
example. The script is run using allocate mode instead
of as a batch job in this case.
.nf
> cat test.sh
#!/bin/sh
echo $SLURM_NODELIST
srun -lN2 -r2 hostname
srun -lN2 hostname
> srun -A -N4 test.sh
dev[7-10]
0: dev9
1: dev10
0: dev7
1: dev8
.fi
.PP
The follwing script runs two job steps in parallel
within an allocated set of nodes.
.nf
> cat test.sh
#!/bin/bash
srun -lN2 -n4 -r 2 sleep 60 &
srun -lN2 -r 0 sleep 60 &
sleep 1
squeue
squeue -s
wait
> srun -A -N4 test.sh
JOBID PARTITION NAME USER ST TIME NODES NODELIST
65641 batch test.sh grondo R 0:01 4 dev[7-10]
STEPID PARTITION USER TIME NODELIST
65641.0 batch grondo 0:01 dev[7-8]
65641.1 batch grondo 0:01 dev[9-10]
.fi
.PP
This example demonstrates how one executes a simple MPICH job.
We use \fBsrun\fR to build a list of machines (nodes) to be used by
\fBmpirun\fR in its required format. A sample command line and
the script to be executed follow.
.nf
> cat test.sh
#!/bin/shMACHINEFILE="nodes.$SLURM_JOBID"
# Generate Machinefile for mpich such that hosts are in the same
# order as if run via srun
#
srun -l /bin/hostname | sort -n | awk '{print $2}' > $MACHINEFILE
# Run using generated Machine file:
mpirun -np $SLURM_NPROCS -machinefile $MACHINEFILE mpi-app
rm $PROCFILE
> srun -AN2 -n4 test.sh
.fi
.SH "BUGS"
If the number of processors per node allocated to a job is not evenly
divisible by the value of \fBcpus\-per\-node\fR, tasks may be initiated
on nodes lacking a sufficient number of processors for the desired parallelism.
For example, if \fBcpus\-per\-node\fR is three, \fBnprocs\fR is four and
the job is allocated three nodes each with four processors. The requisite
12 processors have been allocated, but there is no way for the job to
initiate four tasks with each of them having exclusive access to three
processors on the same node. The \fBnodes\fR and \fBmincpus\fR options
may be helpful in preventing this problem.
.SH "SEE ALSO"
\fBscancel\fR(1), \fBscontrol\fR(1), \fBsqueue\fR(1), \fBslurm.conf\fR(5)