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- Change Control: Public/Stable
- Permissions: The job_sort_formula must be set by the admin (e.g., root).
- Summary: A number between 0 and 1 representing the job's entities usage modified to take it's location in the fairshare tree into account.
- Details:
- A number between 0 and 1. Higher numbers are less deserving.
- This number is somewhat effectivearbitrary. It's based on the actual usage of the entity and its location in the fairshare tree, but isn't directly comparable with any other entity's fairshare_tree_usage.
- NOTE: the formula is calculated once at the start of the cycle. This factor will not be updated during the cycle (e.g., after jobs run).
Interface 2: job_sort_formula keyword "fairshare_factor"
- Change Control: Public/Stable
- Permissions: The job_sort_formula must be set by the admin (e.g., root)
- Summary: Number that allows two entities to be directly compared
- Details:
- A number between 0 and 1. Lower numbers are less deserving
- This number allows two entities anywhere in the tree hierarchy to be compared.
- Low usage entities from high usage groups are negatively affected by their siblings.
- See below for calculations
Interface 3: renaming job_sort_formula keyword: fair_share_perc → fairshare_perc
- Change Control: Public/Stable
- Summary: The job_sort_formula keyword fair_share_perc is deprecated and replaced with fairshare_perc
- Details:
- The renaming is being done to be better aligned with the new fairshare keyword and other fairshare keywords in the sched_config file
Interface
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4: Changes to pbsfs output
- Change Control: Public/Stable
- Summary: print effective usage in pbsfs output
- Details:
- When using pbsfs -g, the effective usage is printed
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Here is a formula to provide a direct comparison between entities. It is not the only one, but it will work well. It results in a number between 0 and 1. A result of .5 means the entity is on fairshare_perc.
2^-(fairshare_tree_usage / entity's fairshare_perc)
This finally allows for a direct comparison between entities, and therefore the jobs that belong to those entities.
This is represented in the job_sort_formula aswith the shorthand keyword 'fairshare_factor' or by using formula math: pow(2, -(fairshare_tree_usage/fairshare_perc))
or in the qmgr commandThere is extra quoting which is required to use formula math. Here is how it is done: qmgr -c 'set server job_sort_formula="pow(2, -(fairshare_tree_usage/fairshare_perc))"'This finally allows for a direct comparison between entities, and therefore the jobs that belong to those entities.
Example:
Share numbers do not need to add up to 100, it just makes the example easier to understand. Entities don't need to all be at the same level of the tree. For example, root could own an entity.
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