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| Please note that job dispatch times are ''estimated''. Alas, we have not mastered the art of writing psychic software yet. | Please note that job dispatch times are ''estimated''. Alas, we have not mastered the art of writing psychic software yet :-) |
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| Build farm jobs can either target a specific platform (e.g. binary builds) or be platform-independent (e.g. "generate a source package from a recipe" builds). The former can only make use of build machines (or "builders" in Soyuz parlance) of the given platform while platform-independent jobs may run on any available builder. |
Build farm jobs can either target a specific platform (e.g. binary builds) or be platform-independent (e.g. "generate a source package from a recipe" builds). The former can only make use of build machines (or "builders" in Soyuz parlance) of the given platform while platform-independent jobs may run on any available builder. |
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| === Problem definition === |
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=== Solution overview === There are two questions we need to answer in order to come up with a dispatch time ''estimation'': 1. how long will the jobs ahead of the JOI (in the pending queue) take to run. This is the ''preliminary lead time'' (PLT). 1. how long will it take until the job at the head of the pending queue is dispatched to a builder (D2)? This is the ''time to next builder'' (TNB). The dispatch time estimation for the JOI is then: now + PLT + TNB. |
Dispatch time estimation for build farm jobs
Introduction
Please note that job dispatch times are estimated. Alas, we have not mastered the art of writing psychic software yet 
For the purpose of this description a 'platform' is considered to be the combination of a
- processor (e.g. i386 or amd64) and a
- virtualization setting (one of: true, false or null)
Build farm jobs can either target a specific platform (e.g. binary builds) or be platform-independent (e.g. "generate a source package from a recipe" builds). The former can only make use of build machines (or "builders" in Soyuz parlance) of the given platform while platform-independent jobs may run on any available builder.
Jobs with an unspecified virtualization setting will be dispatched to virtual builders only.
Builders can -- roughly speaking -- either be idle or building. For any job running on a particular builder its estimated duration and its start time is available allowing us to estimate the job's remaining execution time.
By the way, did I already mention that job dispatch times are an estimation only?
Problem definition
Given:
- a queue of pending (i.e. ready to build) build farm jobs sorted in descending order according to their score
- a pool of builders
Wanted: the estimated dispatch time for a specific job in the pending queue i.e. for the job of interest (aka JOI).
Solution overview
There are two questions we need to answer in order to come up with a dispatch time estimation:
how long will the jobs ahead of the JOI (in the pending queue) take to run. This is the preliminary lead time (PLT).
how long will it take until the job at the head of the pending queue is dispatched to a builder (D2)? This is the time to next builder (TNB).
The dispatch time estimation for the JOI is then: now + PLT + TNB.
