SGE Style Load Sensors

vovtaskers also support SGE style load sensors. Use option -L in vovtasker/vovtaskerroot to define the command line for the load sensor.

For example:

% cp $VOVDIR/etc/tasker_scripts/load_sensor_example.sh /tmp/myloadsensor.sh
% vovtaskerroot -L /tmp/myloadsensor.sh

For security reasons, a load sensor is accepted only if it is owned either by the user or by root.

Load sensors summary:

vovtasker option: -L full_path_to_load_sensor
taskers.tcl file: -loadsensor full_path_to_load_sensor

Execution

The tasker executes the load sensor:

Every minute
After the termination of a job

Special Variables

The implementation recognizes the following special variable names:


Variable name	Description
power	Overrides the effective power of the tasker.
maxload	Overrides the predefined value of max load allowed by the tasker.

All other variable names are added to the resource list for the tasker that is executing the load sensor.

Example of a Load Sensor

The following example can be found in $VOVDIR/etc/tasker_scripts/load_sensor_example.sh.

#!/bin/sh
### This is the classical example of a load sensor for SGE.
### Usage:  % vovtasker -L /full/path/to/load/sensor

myhost=`uname -n | awk -F. '{print $1}'`
myid=`id -u`

while [ 1 ]; do
     # wait for input
     read input
     result=$?
     if [ $result != 0 ]; then
          exit 1
     fi
     if [ "$input" == quit ]; then
          exit 0
     fi 

     echo "Computing load sensor: $input"

     #
     # Send:
     #  1. Number of users logged in
     #  2. Another number, just for fun.
     #  3. Change the power of the tasker to affect the preference
     #  
     logins=`who | cut -f1 -d" " | sort | uniq | wc -l`
     logins=`/bin/echo $logins` # Trim left white space.
     echo begin
     echo "$myhost:logins:$logins"
     echo "$myhost:id:$myid"
     echo "$myhost:power:42222"
     echo end
done

# We never get here.
exit 0