Platform LSF Administration Guide Version 6.2
Chapter 29
Runtime Resource Usage Limits
Administering Platform LSF
467
Supported Resource Usage Limits and Syntax
Core file size limit
Sets a per-process (soft) core file size limit in KB for each process that belongs to this
batch job. On some systems, no core file is produced if the image for the process is larger
than the core limit. On other systems only the first
core_limit KB of the image are
dumped. The default is no soft limit.
CPU time limit
Sets the soft CPU time limit to cpu_limit for this batch job. The default is no limit. This
option is useful for avoiding runaway jobs that use up too many resources. LSF keeps
track of the CPU time used by all processes of the job.
When the job accumulates the specified amount of CPU time, a SIGXCPU signal is sent
to all processes belonging to the job. If the job has no signal handler for SIGXCPU, the
job is killed immediately. If the SIGXCPU signal is handled, blocked, or ignored by the
application, then after the grace period expires, LSF sends SIGINT, SIGTERM, and
SIGKILL to the job to kill it.
You can define whether the CPU limit is a per-process limit enforced by the OS or a per-
job limit enforced by LSF with LSB_JOB_CPULIMIT in
lsf.conf.
Jobs submitted to a chunk job queue are not chunked if the CPU limit is greater than 30
minutes.
Format
cpu_limit is in the form [hour:]minute, where minute can be greater than 59. 3.5 hours
can either be specified as 3:30 or 210.
Normalized CPU
time
The CPU time limit is normalized according to the CPU factor of the submission host
and execution host. The CPU limit is scaled so that the job does approximately the same
amount of processing for a given CPU limit, even if it is sent to a host with a faster or
slower CPU.
For example, if a job is submitted from a host with a CPU factor of 2 and executed on
a host with a CPU factor of 3, the CPU time limit is multiplied by 2/3 because the
execution host can do the same amount of work as the submission host in 2/3 of the
time.
If the optional host name or host model is not given, the CPU limit is scaled based on
the DEFAULT_HOST_SPEC specified in the
lsb.params file. (If
DEFAULT_HOST_SPEC is not defined, the fastest batch host in the cluster is used as
the default.) If host or host model is given, its CPU scaling factor is used to adjust the
actual CPU time limit at the execution host.
The following example specifies that
myjob can run for 10 minutes on a DEC3000
host, or the corresponding time on any other host:
Job syntax (bsub) Queue syntax (lsb.queues) Fomat/Units
-C core_limit
CORELIMIT=
limit
integer KB
Job syntax (bsub) Queue syntax (lsb.queues) Fomat/Units
-c cpu_limit
CPULIMIT=[
default
]
maximum
[hours:]minutes[/host_name |
/host_model]