Sudden, persistent extremely low tickrate, biters involved

[Reika]

At a - seemingly random - point in my save, the tickrate started plummeting (i.e. went from 60 to 20 TPS in a matter of a few minutes) and has remained there permanently.
It goes away temporarily if I clear all enemies, but gradually returns within 15 seconds. This to me indicates that biters are involved somehow, and that many, many more than the typical numbers are involved.

I do have a massive pollution cloud, but even getting rid of the pollution has no effect; distant biter colonies still appear to continuously spawn new "actively updating" biters over time, rather than the inert grid-aligned ones seen in "dark" unloaded chunks.

Is it because I have too large of an area "active scanned" by the radars? I do notice that they are starting to glitch out on the main map; that is, a "line scanning" effect similar to old VCRs is starting to appear in the normally solidly-lit areas.

EDIT: Reducing the radar range does not help on its own, but clearing all enemies as well makes the lag-removing effect last much longer than before. However, the lag still returns, just now taking about 2 minutes to do so.

Here is a screenshot detailing profiling info:
http://i.imgur.com/UFbP7v8.jpg

For reference, I have 8 threads dedicated to the game and it still only uses <15% of my CPU.

[Rseding91]

Can you post your save file so I can profile it and see what's taking so much tick time?

[TuckJohn]

It sounds like a very similar problem that I encountered in one of my old saves- I explored extremely far north,and, with all of the biters that were spawned and spawning, my UPS never got about 20.

[Reika]

Can you post your save file so I can profile it and see what's taking so much tick time?

Done.

http://www.mediafire.com/download/wgwp5 ... z/mods.rar

http://www.mediafire.com/download/c6vin ... trains.zip

[ssilk]

If it is as with me, then it is the pathfinding. I have currently "dropouts" of 20 seconds or so (but my map is much bigger).

I recommend this (as a fix until the more intelligent pathfinder works): If the distance is too far (hm, > 300 tiles?) then the pathfinder checks only a path in a very small "corridor", which is a direct line between source and target.

If nothing found it might try other paths; for example it searches for the nearest start of an already existing path - but in the next tick, not now. Otherwise the biters just die, because they don't find a target.