Dwarf Fortress Bug Tracker - Dwarf Fortress
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0003164Dwarf FortressPathfindingpublic2010-09-06 09:422014-08-08 16:25
normalminorhave not tried
0003164: Severe lag during sieges due to buildingdestroyer pathfinding
During my fortress's most recent siege, the pathfinding from the numerous trolls managed to drag my framerate from its usual 25fps down to 4fps. In previous sieges where the trolls were the first to reach my fortress, the framerate increased significantly once they had been killed or captured.

If I seal the entrance to my fortress (using a drawbridge that lowers on top of a downward ramp, the lag similarly subsides once the trolls stop trying to path into my fortress.

Early sieges (which did not yet include any trolls) did not cause any significant lag.
BUILDINGDESTROYER, pathfinding, siege
related to 0001340new  Walling off HFS kills FPS 
related to 0010540confirmed Loci Closed bridge impact vastly the fps in this siege 
Issue History
2010-09-06 09:42QuietustNew Issue
2010-09-08 03:14behbehrNote Added: 0012497
2010-09-08 03:48behbehrIssue Monitored: behbehr
2010-09-08 04:32KennelTag Attached: pathfinding
2010-09-08 04:32KennelTag Attached: siege
2010-09-10 08:56hyndisNote Added: 0012560
2013-09-22 17:35FootkerchiefRelationship addedrelated to 0001340
2013-09-22 17:35FootkerchiefTag Attached: BUILDINGDESTROYER
2014-08-08 16:25FootkerchiefAssigned To => Footkerchief
2014-08-08 16:25FootkerchiefStatusnew => confirmed
2018-01-21 14:59DetrosRelationship addedrelated to 0010540
2018-04-25 16:11HuntthetrollIssue Monitored: Huntthetroll

2010-09-08 03:14   
Can confirm this. Every time my fortress is under sieged by trolls, my framerate goes from 20-25 down to 4-5 until they've been killed or they run away.
This can be reproduced every time a siege with trolls appear.
2010-09-10 08:56   
Old bug, happened with the earlier versions like 40D, and even the version previous to that. A single building destroyer doesn't make a very large FPS hit, but many of them, like armies of trolls, will kill your FPS every time.