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IDProjectCategoryView StatusDate SubmittedLast Update
0008442Dwarf FortressPathfindingpublic2014-10-18 05:452017-05-06 14:37
Reporterchoopm Assigned To 
PrioritynormalSeverityblockReproducibilityN/A
Status newResolutionopen 
Platformx86_64OSArch LinuxOS Version-
Product Version0.40.13 
Summary0008442: <5 FPS, 100% CPU Usage: Stuck dwarf interrupts others
DescriptionI don't know exactly how to reproduce it, but it's the second time in 2 different regions, where a dwarf gets stuck in my stair tower:

It seems to be a pathfinding algorithm which eats up the CPU and let's the FPS drop towards 0 and so, leaves the game nearly unplayable.
I didn't notice if the dwarf got stuck before or after he was taken by a fey mood.
See the savegame: http://www.0pointer.org/~choopm/stuckmidair-region.zip

It's my chief medical dwarf flying on -13 Z-levels from the wagon spawn (F1).
If k-looked onto the tile, it clearly says "Open Space".
I wonder how a stuck dwarf could interrupt other dwarves. If I zoom to the location hilighted in announcements, it takes me near where the dwarf should have been if he wasn't stuck.

Sorry for the few informations I could provide :(
Steps To Reproducesee description
Additional Informationsee description
TagsNo tags attached.

Relationships

related to 0007998 confirmeduser6 Area above mushroom "walls" classified as open space, dropping onto it causes you to fall forever then crash 
related to 0008324 new Imprisoned Were-creature brings FPS to crawling hold 

Activities

choopm

2014-10-19 03:29

reporter   ~0030670

Update: I let the game up and running for a few hours.
The moment the chief medical dwarf went insane because of his dehydration it cancels the strange mood order. The game is now running smooth again.

So it seems the issue here might be:
If a dwarf get's into a strange mood and is trapped or stuck in your fortress, the pathfinding algorithm will be started over and over again. This results in 100% CPU usage and minimum FPS.

One approach could be a priority system, e.g. if a dwarf's path finding fails, it would get more and more less attention every frame iteration to a minimum where it would try to find a path every minute.

Kirkegaard

2014-10-19 06:35

reporter   ~0030672

I have also seen this, once with an cave swallow that somehow teleported itself into my stair area and tried to patch out. It can also happen if you use dfhack reveal and unreveal and some dwarfs get stuck in the "unknown area" instantly dropping fps to 0.

Lac

2014-10-19 09:55

reporter   ~0030673

We've had cases of stuck dwarfs in fey moods causing fps drop before; but they've been marked resolved: 0007284. Maybe Toady just addressed the sticking issue and there's other ways to get stuck.

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Issue History

Date Modified Username Field Change
2014-10-18 05:45 choopm New Issue
2014-10-19 03:29 choopm Note Added: 0030670
2014-10-19 06:35 Kirkegaard Note Added: 0030672
2014-10-19 09:55 Lac Note Added: 0030673
2014-11-19 12:36 user6 Relationship added related to 0007998
2017-05-06 14:37 lethosor Relationship added related to 0008324