LSF Version 7.3 - Administering Platform LSF

Dynamic User Priority
298 Administering Platform LSF
Assigns 27 shares: 10 to User1, 9 to User2, and 8 to the remaining users, as a group.
User1 is slightly more important than User2. Each of the remaining users has equal
importance.
◆ If there are 3 users in total, the single remaining user has all 8 shares, and is
almost as important as
User1 and User2.
◆ If there are 12 users in total, then 10 users compete for those 8 shares, and each
of them is significantly less important than
User1 and User2.
[User1, 10] [User2, 6] [default, 4]
The relative percentage of shares held by a user will change, depending on the
number of users who are granted shares by default.
◆ If there are 3 users in total, assigns 20 shares: 10 to User1, 6 to User2, and 4 to
the remaining user.
User1 has half of the available resources (10 shares out of
20).
◆ If there are 12 users in total, assigns 56 shares: 10 to User1, 6 to User2, and 4 to
each of the remaining 10 users.
User1 has about a fifth of the available resources
(10 shares out of 56).
Dynamic User Priority
LSF calculates a dynamic user priority for individual users or for a group, depending
on how the shares are assigned. The priority is dynamic because it changes as soon
as any variable in formula changes. By default, a user’s dynamic priority gradually
decreases after a job starts, and the dynamic priority immediately increases when
the job finishes.
How LSF calculates dynamic priority
By default, LSF calculates the dynamic priority for each user based on:
◆ The number of shares assigned to the user
◆ The resources used by jobs belonging to the user:
❖ Number of job slots reserved and in use
❖ Run time of running jobs
❖ Cumulative actual CPU time (not normalized), adjusted so that recently
used CPU time is weighted more heavily than CPU time used in the distant
past
If you enable additional functionality, the formula can also involve additional
resources used by jobs belonging to the user:
◆ Historical run time of finished jobs
◆ Committed run time, specified at job submission with the -W option of bsub, or
in the queue with the RUNLIMIT parameter in
lsb.queues
How LSF measures fairshare resource usage
LSF measures resource usage differently, depending on the type of fairshare:
◆ For user-based fairshare: