Platform LSF Administration Guide Version 6.2

Load Thresholds
Administering Platform LSF
556
Load Thresholds
Load threshold parameters define the conditions beyond which a host is considered
busy by LIM and are a major factor in influencing performance. No jobs will be
dispatched to a busy host by LIM’s policy. Each of these parameters is a load index value,
so that if the host load goes beyond that value, the host becomes busy.
LIM uses load thresholds to determine whether to place remote jobs on a host. If one
or more LSF load indices exceeds the corresponding threshold (too many users, not
enough swap space, etc.), then the host is regarded as busy and LIM will not recommend
jobs to that host.
Thresholds can be set for any load index supported internally by the LIM, and for any
external load index.
If a particular load index is not specified, LIM assumes that there is no threshold for that
load index. Define looser values for load thresholds if you want to aggressively run jobs
on a host.
See “Load Thresholds” on page 473 for more details.
In this section
◆ “Load indices that affect LIM performance” on page 556
◆ “Comparing LIM load thresholds” on page 556
◆ “If LIM often reports a host as busy” on page 557
◆ “If interactive jobs slow down response” on page 557
◆ “Multiprocessor systems” on page 557
Load indices that affect LIM performance
For more details on load indices see “Load Indices” on page 209.
Comparing LIM load thresholds
To tune LIM load thresholds, compare the output of lsload to the thresholds reported
by
lshosts -l.
The
lsload and lsmon commands display an asterisk * next to each load index that
exceeds its threshold.
Example
Consider the following output from lshosts -l and lsload:
Load index Description
r15s 15-second CPU run queue length
r1m 1-minute CPU run queue length
r15m 15-minute CPU run queue length
pg Paging rate in pages per second
swp Available swap space
it Interactive idle time
ls Number of users logged in