[slurm-users] FairShare

Ryan Cox ryan_cox at byu.edu
Wed Dec 2 17:45:30 UTC 2020


That is not for Fair Tree, which is what Micheal asked about.

Ryan

On 12/2/20 10:32 AM, Renfro, Michael wrote:
>
> Yesterday, I posted https://docs.rc.fas.harvard.edu/kb/fairshare/ 
> <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdocs.rc.fas.harvard.edu%2Fkb%2Ffairshare%2F&data=04%7C01%7Crenfro%40tntech.edu%7Cc23f89dcb97743ee5eda08d8960679ed%7C66fecaf83dc04d2cb8b8eff0ddea46f0%7C1%7C1%7C637424301864169250%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000&sdata=%2FnB4ivZeDNrVZiaeupFnAj86oQLOhMu1%2FK6YiuBxTB8%3D&reserved=0>in 
> response to a similar question. If you want the simplest general 
> explanation for FairShare values, it's that they range from 0.0 to 
> 1.0, values above 0.5 indicate that account or user has used less than 
> their share of the resource, and values below 0.5 indicate that that 
> account or user has used more than their share of the resource.
>
> Since all your users have the same RawShares value and are entitled to 
> the same share of the resource, you can see that bdehaven has the most 
> RawUsage and the lowest FairShare value, followed by ajoel and xtsao 
> with almost identical RawUsage and FairShare, and finally ahantau with 
> very little usage and the highest FairShare value.
>
> We use FairShare here as the dominant factor in priorities for queued 
> jobs: if you're a light user, we bump up your priority over heavier 
> users, and your job starts quicker than those for heavier users, 
> assuming all other job attributes are equal.
>
> All these values are relative: in our setup, we'd bump ahantau's 
> pending jobs ahead of the others, and put bdehaven's at the end. But 
> if root needed to run a job outside the sray account, they'd get an 
> enormous bump ahead since the sray account has used far more than its 
> fair share of the resource.
>
> *From: *slurm-users <slurm-users-bounces at lists.schedmd.com>
> *Date: *Wednesday, December 2, 2020 at 11:23 AM
> *To: *slurm-users at lists.schedmd.com <slurm-users at lists.schedmd.com>
> *Subject: *Re: [slurm-users] FairShare
>
> *External Email Warning*
>
> *This email originated from outside the university. Please use caution 
> when opening attachments, clicking links, or responding to requests.*
>
> ------------------------------------------------------------------------
>
> I've read the manual and I re-read the other link. What they boil down 
> to is Fair Share is calculated based on a recondite "rooted plane 
> tree", which I do not have the background in discrete math to understand.
>
> I'm hoping someone can explain it so my little kernel can understand.
>
> ------------------------------------------------------------------------
>
> *From:*slurm-users <slurm-users-bounces at lists.schedmd.com> on behalf 
> of Micheal Krombopulous <MichealKrombopulous at outlook.com>
> *Sent:* Wednesday, December 2, 2020 9:32 AM
> *To:* slurm-users at lists.schedmd.com <slurm-users at lists.schedmd.com>
> *Subject:* [slurm-users] FairShare
>
> Can someone tell me how to calculate fairshare (under fairtree)? I 
> can't figure it out. I would have thought it would be the same score 
> for all users in an account. E.g., here is one of my accounts:
>
> Account     User  RawShares  NormShares    RawUsage NormUsage 
>  EffectvUsage    LevelFS  FairShare
> -------------------- ---------- ---------- ----------- ----------- 
> ----------- ------------- ---------- ----------
> root  0.000000      611349                  1.000000
>  root                      root             1  0.076923           0   
>  0.000000      0.000000  inf   1.000000
>  sray                                          1  0.076923     
>  30921 0.505582      0.505582   0.152147
>   sray                 phedge            1    0.050000         0   
>  0.000000      0.000000        inf 0.181818
>   sray                raab                  1  0.050000           0   
>  0.000000      0.000000  inf   0.181818
>   sray                benequist          1    0.050000         0   
>  0.000000      0.000000        inf 0.181818
>   sray                 bosch               1    0.050000           0   
>  0.000000      0.000000        inf 0.181818
>   sray                rjenkins             1    0.050000           0   
>  0.000000      0.000000        inf 0.181818
>   sray                  esmith            1    0.050000           0   
>  0.000000      0.000000 1.7226e+07 0.054545
>   sray                  gheinz            1    0.050000           0   
>  0.000000      0.000000 1.9074e+14 0.072727
>   sray                  jfitz                 1  0.050000           0 
>    0.000000      0.000000 8.0640e+20   0.081818
>   sray                   ajoel              1  0.050000       42449   
>  0.069465      0.137396 0.363913   0.018182
>   sray                  jmay               1    0.050000           0   
>  0.000000      0.000000        inf 0.181818
>   sray                 aferrier            1    0.050000           0   
>  0.000000      0.000000        inf 0.181818
>   sray                bdehaven         1    0.050000  225002   
>  0.367771      0.727420   0.068736   0.009091
>   sray                msmythe          1    0.050000       0   
>  0.000000      0.000000        inf   0.181818
>   sray                 gfink               1    0.050000           0   
>  0.000000      0.000000 2.0343e+05 0.045455
>   sray                ahantau           1    0.050000        31   
>  0.000051      0.000102 491.737549 0.036364
>   sray                 hmiller            1    0.050000           0   
>  0.000000      0.000000        inf 0.181818
>   sray                   ttinker          1    0.050000           0   
>  0.000000      0.000000 1.4798e+13 0.063636
>   sray                wcooper          1    0.050000       0   
>  0.000000      0.000000        inf   0.181818
>   sray                 xtsao              1    0.050000       41734   
>  0.068296      0.135083   0.370143 0.027273
>   sray                   xping            1    0.050000           0   
>  0.000000      0.000000 1.9833e+24 0.090909
>

-- 
Ryan Cox
Director
Office of Research Computing
Brigham Young University

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