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-boun...@lists.schedmd.com>
Date: Wednesday, December 2, 2020 at 11:23 AM
To: slurm-users@lists.schedmd.com <slurm-users@lists.schedmd.com>
Subject: Re: [slurm-users] FairShare
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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-boun...@lists.schedmd.com> on behalf of Micheal
Krombopulous <michealkrombopul...@outlook.com>
Sent: Wednesday, December 2, 2020 9:32 AM
To: slurm-users@lists.schedmd.com <slurm-users@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
