Platform LSF Administration Guide Version 6.2

Chapter 28
Running Parallel Jobs
Administering Platform LSF
439
Running Parallel Processes on Homogeneous Hosts
Parallel jobs run on multiple hosts. If your cluster has heterogeneous hosts some
processes from a parallel job may for example, run on Solaris and some on SGI IRIX.
However, for performance reasons you may want all processes of a job to run on the
same type of host instead of having some processes run on one type of host and others
on another type of host.
You can use the
same section in the resource requirement string to indicate to LSF that
processes are to run on one type or model of host. You can also use a custom resource
to define the criteria for homogeneous hosts.
Examples
Running all parallel processes on the same host type
% bsub -n 4 -R"select[type==SGI6 || type==SOL7] same[type]"
myjob
Allocate 4 processors on the same host type—either SGI IRIX, or Solaris 7, but not
both.
Running all parallel processes on the same host type and model
% bsub -n 6 -R"select[type==any] same[type:model]" myjob
Allocate 6 processors on any host type or model as long as all the processors are on the
same host type and model.
Running all parallel processes on hosts in the same high-speed connection group
% bsub -n 12 -R "select[type==any && (hgconnect==hg1 || hgconnect==hg2 ||
hgconnect==hg3)] same[hgconnect:type]" myjob
For performance reasons, you want to have LSF allocate 12 processors on hosts in high-
speed connection group
hg1, hg2, or hg3, but not across hosts in hg1, hg2 or hg3 at
the same time. You also want hosts that are chosen to be of the same host type.
This example reflects a network in which network connections among hosts in the same
group are high-speed, and network connections between host groups are low-speed.
In order to specify this, you create a custom resource
hgconnect in lsf.shared.
Begin Resource
RESOURCENAME TYPE INTERVAL INCREASING RELEASE DESCRIPTION
hgconnect STRING () () () (OS release)
...
End Resource
In the lsf.cluster.cluster_name file, identify groups of hosts that share high-speed
connections.
Begin ResourceMap
RESOURCENAME LOCATION
hgconnect (hg1@[hostA hostB] hg2@[hostD hostE] hg3@[hostF hostG hostX])
End ResourceMap