Thanks for the reply Ryan,

Yes, I’m using the basic fairshare.  I am trying to use fairshare across a flat 
listing of users only, with a placeholder parent account called ‘dev’, but for 
now, it has no siblings.  All users are under ‘dev’.

I think the way it is calculated, in my configuration, the largest fairshare I 
will ever see is 0.5.

F = 2**(-Ue/S),   where in my case S = 1000 / 16000  (1000 per user, 16 users 
(who each have 1000))
and I have Ue =S  for a user who never submit a job yet    because Ue = 0 
(Uactual) + (1.0  – 0.0)*1000/16000   (1.0 is parent usage, which is always 1.0 
in my case because dev is the only parent account for any user)

I was expecting/hoping/wishing the values would be between 0.0 and 1.0, but I 
can work with 0.5 as the max value.  It just means that I need to double the 
PriorityWeightFairshare factor in order to achieve the intended relative 
weighting between Fairshare, QOS, Partitions, JobSize, Age.

Ed


From: Ryan Cox [mailto:[email protected]]
Sent: Tuesday, October 14, 2014 6:00 PM
To: slurm-dev
Subject: EXTERNAL: [slurm-dev] Re: question on multifactor priority plugin - 
fairshare basics

I assume you are using the default fairshare algorithm since you didn't specify 
otherwise.  F=2**(-U/S) where U is Effectv Usage (often displayed in 
documentation as UE) and S is Norm Shares.  See 
http://slurm.schedmd.com/priority_multifactor.html under the heading "The SLURM 
Fair-Share Formula".

Basically, Effectv Usage needs to be less than Norm Shares for Fairshare to be 
greater than 0.5.

Ryan
On 10/14/2014 04:27 PM, Blosch, Edwin L wrote:
I must be misunderstanding a basic concept here.

What conditions would have to exist to cause a Fairshare value greater than 0.5?


[bloscel@maruhpc5 ~]$ sshare -a
             Account       User Raw Shares Norm Shares   Raw Usage Effectv 
Usage  FairShare
-------------------- ---------- ---------- ----------- ----------- 
------------- ----------
root                                          1.000000    11376527      
1.000000   0.500000
 root                      root          0    0.000000           0      
0.000000   0.000000
 cfd                                     1    1.000000    11376527      
1.000000   0.500000
  cfd                   bendeee       1000    0.076923           0      
0.076923   0.500000
  cfd                   bloscel       1000    0.076923      712296      
0.134718   0.297027
<more users under same group>


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