5.1.4 Prioritization Strategies

Each component or subcomponent may be used to accomplish different objectives. WALLTIME can be used to favor (or disfavor) jobs based on their duration. Likewise, ACCOUNT can be used to favor jobs associated with a particular project while QUEUETIME can be used to favor those jobs which have been waiting the longest.

- Queue Time
- Expansion Factor
- Resource
- Fairshare
- Cred
- Target Metrics

Each priority factor group may contain one or more subfactors. For example, the Resource factor consists of Node, Processor, Memory, Swap, Disk, and PE components. Figure <X> shows the current priority breakdown. From the figure, it is quickly apparent that the prioritization problem is fairly 'nasty' due to the fact that every site needs to prioritize a bit differently. Fortunately, there has not yet been a site that has desired to use more than a fraction of these priority factors, thus greatly simplifying the job priority tuning issue. When calculating a priority, the various priority factors are summed and then bounded between 0 and MAX_PRIO_VAL which is currently defined as 100000000 (one billion).

Each priority factor is reviewed in detail below. The command 'diagnose -p' is designed to assist in visualizing the priority distribution resulting from the current job priority configuration. Also, the showgrid command will help indicate the impact of the current priority settings on scheduler service distributions.