Okay, I get it now. All the shares under a given ACCOUNT add up to 1.0.
The divvy, and why some are higher than the actual ACCOUNT's number,
is merely the effect from this allocation amongst the users underneath.
So if the ACCOUNT gets 20% (0.20 or nearly so), then all the users
underneath, when summed, have a value of 1.0. Because a user here gets
a bigger cut by assignment of a fairshare value >1 then just because
that user has a value exceeding the ACCOUNT value is not to be confused
with a fairshare exceeding that of it's parent. Only that the value of
the parent's fairshare, that user gets this percentage of the cut.
Got it!
Thanks much,
Bill
On 1/21/2015 12:57 PM, Ryan Cox wrote:
On 01/21/2015 09:23 AM, Bill Wichser wrote:
A user underneath gets the expected 0.009091 normalized shares since
there are a lot of fairshare=1 users there. The user3 gets basically
25x this value as the fairshare for user3=25
Yet the normalized shares is actually MORE than the normalized shares
for the account as a whole. What should I make of this?
This is actually by design in Fair Tree and is different from other
algorithms. The manpage for sshare covers this under "FAIR_TREE
MODIFICATIONS". The manpage states that Norm Shares is "The shares
assigned to the user or account normalized to the total number of
assigned shares within the level." Basically, the Norm Shares is the
association's raw shares value divided by the sum of it and its sibling
associations' assigned raw shares values. For example, if an account
has 10 users, each having 1 assigned raw share, the Norm Shares value
will be .1 for each of those users under Fair Tree.
Fair Tree only uses Norm Shares and Effective Usage (the other sshare
field that's modified) when comparing sibling associations. Our Slurm UG
presentation slides also mention this on pages 35 and 76
(http://slurm.schedmd.com/SUG14/fair_tree.pdf).
Ryan
