lsb.threshold

The lsb.threshold configuration file defines energy-saving and CPU frequency policies. This file is optional.

The threshold file (lsb.threshold) is available at the location specified by the parameter PERFORMANCE_THRESHOLD_FILE in the lsb.params file. The default location is $LSF_ENVDIR/lsbatch/cluster_name/configdir/lsb.threshold.

The threshold file has the following parts:

Minimize energy policy

The purpose of this policy is to save energy. With this policy, LSF will select a frequency that is equal to or less than the default CPU frequency and the time variation is equal to or less than the threshold value, which can save the most energy. The value should be a positive value or 0. The default threshold value is 0.

Minimize time policy

The purpose of this policy is to improve performance. The value must be a negative value. This policy allows the job to run at a frequency that is higher than the default frequency. The policy is only available when the default frequency is less than the nominal frequency.

LSF only considers the frequency range that is higher than the default frequency. When a job runs with this policy, LSF checks the time variation from the nominal to the default frequency. The frequency is used for the job when the time variation is less than or equal to the corresponding threshold value (the absolute value of time variation is large than or equal to corresponding threshold’s absolute value); otherwise, LSF checks the next frequency.

The job will run in the default frequency when there is no frequency that matches the specified threshold value. You must specify at least one frequency value that is larger than the default CPU frequency and less than or equal to the maximum available frequency. The available frequency list is available at /sys/devices/system/cpu/cpu*/cpufreq/scaling_available_frequencies. If it is not in the available frequency list, the frequency will be ignored. For other frequencies larger than the default CPU frequency, LSF automatically calculates the value based on the difference of default frequency and defined frequency. LSF will calculate the increase between each frequency and use that to get all frequencies that are larger than the default CPU frequency.

The following is an example lsb.threshold file:

# Copyright International Business Machines Corp,1993-2006, 2013
#....
# Minimize energy policy
#.....
Begin Min_Energy
THRESHOLD_RUNTIME_VAR = 10
End  Min_Energy
#
# Minimize run time policy
#...
Begin Min_Time
CPU_FREQ       RUNTIME_VAR
2100000KHz     -2      
2200000KHz     -4
2300000KHz     -9
2400000KHz     -12
2500000KHz     -15
2700000KHz     -20
End Min_Time

Example definitions are commented with a pound sign (#) in the sample lsb.threshold file. Remove the # to enter your own values for the example definitions. If no lines are uncommented, default values will be used for all definitions.