[GE users] user feels penalized by share tree
Shannon V. Davidson
svdavidson at swbell.net
Wed Jun 2 18:13:28 BST 2004
Sebastian / Andy,
You could charge less during non-peak periods by adjusting the execution
host's cpu usage scaling factor:
% qconf -mattr exechost usage_scaling cpu=0.1 <exec-host-name>
or you could implement a simple brokerage system with a monitoring
script which sets the cpu usage scaling factor for a host based on how
many jobs are waiting to run on that host:
if [ "$host" = "" ]; then
echo usage: `basename $0` hostname
while [ 1 = 1 ]; do
jobs=`qstat -s p -l h=$host | egrep -v "^job-ID|^-----" | wc -l`
if [ $jobs -eq 0 ]; then
cpu_scale=`echo "scale=2; 1.0 - (1.0 / ($jobs+1))" | bc`
echo $jobs jobs are queued for $host, Setting CPU scaling factor
qconf -mattr exechost usage_scaling cpu=$cpu_scale $host
Andy Schwierskott wrote:
>>One of my users was complaining about being penalized by the share tree policy
>>if he's using the cluster when otherwise it would be idle. Let us assume the
>>There are 20 nodes, 15 of which are free (have no job running) at night. The
>>user thinks it would be a good time to submit his jobs (which is not wrong).
>>Say he submits 12 jobs which run all the night.
>>On the next day, when other users are submitting jobs, he will have bad karma
>>(=less tickets) and feel 'penalized' for using the idle time of the cluster.
>>I couldn't find a way to argue against that nor could I find a way to
>>'fix' that behaviour in SGE.
>This behavior can't be "fixed" in a clean way today - the fix would be to
>introduce a brokerarge system where the "price" of resources depends on the
>demand for them.
>There are many good arguments why the implementation as it is today can be
>seen as fair - see the analogy to an empty hotel: you usually pay the same
>rate regardless of the number of guests. The user requested resources which
>were granted - from a global perspective it's certainly fair to argue that
>you have to pay for it.
>>I'm running SGEEE 5.3p5 with a quite simple share tree and evenly distributed
>>tickets. Does someone have an idea how I could make the system 'feel a bit
>If you are in the opinion that the behavior treats your users unfair, you
>may reduce the halflife time of the sharetree. Setting it to a few hours
>would decay past usage much faster.
>You also might consider to reset the sharetree usage every morning if a mid-
>or longterm fairs share is not an objective at your site. Or you may set the
>sharetree to e.g. 24 hours during day time and to a very short time (a few
>hours) during night time.
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