Feature request: Abstractified Cleaning Zones

[ErioirE]

I notice cleaning tasks can have a disproportionate effect on performance. Have you considered abstracting it such that (indoor) rooms are treated as 1 "unit to be cleaned" rather than the pawn job searcher having to search over every mess instance in every room, you could just have an average mess rating per area and when a pawn works on a particular area they would just sweep random adjacent tiles in sequence in the respective room and each time sufficient work is completed you would remove 1 mess object at random.
Assuming I've explained it in a coherent way (and that the existing code works approximately the way I assume it does), I expect this would drastically reduce the performance cost while retaining the effective functionality (you would still have the same 'messes' visually, the only abstraction is in how they are cleaned.)
So my questions:

1. Is this approach likely to have significant benefits vs current code?
2. Is this approach something you think would fit with this mod?
3. Is it feasible enough that you are willing to consider doing it?

If 1 is yes but 2 and/or 3 are no, would you be willing to give me pointers as to what I'd need to override to make my own mod and implement it myself? I'm a software dev who specializes in C# and I've done unity game modding in the past, just not for Rimworld.

Thanks, ~ David

[bbradson]

The existing cleaning implementation within RimWorld.WorkGiver_CleanFilth already works mildly similarly to that. Rimworld has the map divided into regions with a size of up to 12x12, separated by impassable cells. Each such region has a lister containing cached lists of things by def and by group, including a group for Filth. The workgiver then does its lookup by traversing regions and checking these listers for filth. A mapwide search is done after hitting the limit for checked regions, seemingly 4 at the moment.

I'd imagine a very simple performance optimization can be implemented here by making the limit more dynamic. Replacing the BreadthFirst search with something making better use of caches would remove the need for these limitations, but would probably also require replacing the whole filth workgiver with a subclass of RimWorld.WorkGiver that implements NonScanJob. WorkGiver_Scanner always uses the lookups implemented in RimWorld.JobGiver_Work.TryIssueJobPackage, with those scanners only providing the search sets and predicates. It may require compatibility adjustments for other mods patching WorkGiver_CleanFilth.

Patching RimWorld.WorkGiver_CleanFilth.MaxRegionsToScanBeforeGlobalSearch is simple enough to just add in a small performance fish update. Anything beyond that won't be done by me, but I'd be happy to help with questions. I'm active on discord too, dub's server or the rimworld server.

[bbradson]

Performance Fish has a patch doing essentially the reverse of this implemented for other jobs. It prevents region based searches when seeing a map wide collection that is small enough to be reasonably likely to be faster to search through. https://github.com/bbradson/Performance-Fish/blob/main/Source/PerformanceFish/JobSystem/GenClosestPatches.cs