[slurm-users] GrpTRESMins and GrpTRESRaw usage

[Ole Holm Nielsen]

Hi Bjørn-Helge,

On 6/23/22 09:18, Bjørn-Helge Mevik wrote:
> <gerard.gil at cines.fr> writes:
> 
>> TRESRaw cpu is lower than before as I'm alone on the system an no other job was submitted.
>> Any explanation of this ?
> 
> I'd guess you have turned on FairShare priorities.  Unfortunately, in
> Slurm the same internal variables are used for fairshare calculations as
> for GrpTRESMins (and similar), so when fair share priorities are in use,
> slurm will reduce accumulated GrpTRESMins over time.  This means that it
> is impossible(*) to use GrpTRESMins limits and fairshare
> priorities at the same time.

This is a surprising observation!  We use a 14 days HalfLife in slurm.conf:
PriorityDecayHalfLife=14-0

Since our longest running jobs can run only 7 days, maybe our limits never 
get reduced as you describe?

The slurm.conf man-page says that PriorityDecayHalfLife affects hard time 
limits per association:

>        PriorityDecayHalfLife
>               This controls how long  prior  resource  use  is  considered  in
>               determining how over- or under-serviced an association is (user,
>               bank account and cluster)  in  determining  job  priority.   The
>               record  of  usage  will  be  decayed over time, with half of the
>               original value cleared at age PriorityDecayHalfLife.  If set  to
>               0  no  decay  will  be  applied.  This is helpful if you want to
>               enforce hard time limits per association.  If set to  0  Priori‐
>               tyUsageResetPeriod  must  be  set  to some interval.  Applicable
>               only if PriorityType=priority/multifactor.  The unit is  a  time
>               string  (i.e.  min, hr:min:00, days-hr:min:00, or days-hr).  The
>               default value is 7-0 (7 days).

Is this what explains your statement?

BTW, I've written a handy script for displaying user limits in a readable 
format:
https://github.com/OleHolmNielsen/Slurm_tools/tree/master/showuserlimits

/Ole