We're trying to figure out what the intended behavior of
Fairshare=parent is when set on an account
(http://bugs.schedmd.com/show_bug.cgi?id=864). We know what the actual
behavior is but we're wondering if anyone actually likes the current
behavior. There could be some use case out there that we don't know about.
For example, you can end up with a scenario like the following:
acctProf
/ | \
/ | \
acctTA(parent) uD(5) uE(5)
/ | \
/ | \
uA(5) uB(5) uC(5)
The number in parenthesis is Fairshare according to sacctmgr. We
incorrectly thought that Fairshare=parent would essentially collapse the
tree so that uA - uE would all be on the same level. Thus, all five
users would each get 5 / 25 shares.
What actually happens is you get the following shares at the user level:
shares (uA) = 5 / 15 = .333
shares (uB) = 5 / 15 = .333
shares (uC) = 5 / 15 = .333
shares (uD) = 5 / 10 = .5
shares (uE) = 5 / 10 = .5
That's pretty far off from each other, but not as far as it would be if
one account had two users and the other had forty. Assuming this
demonstration value of 5 shares, that would be:
user_in_small_account = 5 / (2*5) = .5
user_in_large_account = 5 / (40*5) = .025
Is that actually useful to someone?
We want to use subaccounts below a faculty account to hold, for example,
a grad student or postdoc who teaches a class. It would be nice for the
grad student to have administrative control over the subaccount since he
actually knows the students but not have it affect priority calculations.
Ryan
--
Ryan Cox
Operations Director
Fulton Supercomputing Lab
Brigham Young University
