c# - Multithreading doesn't work if I start more than 1 other thread -

i don't know if problem unity-specific maybe other c# developers can me :)

so trying implement own version of a* algorithm , improve performance want actual path finding every seeker multi threaded:

it works pretty until moment activate second seeker:

like can see stops after 15 iterations (varying depending on how many text outputs call -> guess threads getting killed after amount of time) in algorithm , first started thread gets kind of killed following.

i using c# threadpool class thread management tried use thread class. same result.

implementation of threading:

public static void requestpath(pathrequest _request) {     debug.log("queueing pathrequest...");     threadpool.queueuserworkitem(instance.startthreadedpathfinding, _request); } 

the called method:

private void startthreadedpathfinding(object _stateinfo) {     pathrequest request = (pathrequest)_stateinfo;     m_pathfinder.findpath(request, onpathfound); } 

and findpath:

public void findpath(pathrequest _request, action<pathresult> _callback) {     debug.log("starting a* algorithm");     binaryheap<node> openlist = new binaryheap<node>(gridsize);     hashset<node> closedlist = new hashset<node>();      node startnode = _request.start;     node targetnode = _request.target;      bool success = false;      openlist.add(startnode);      while (openlist.count > 0)     {         debug.log(thread.currentthread.managedthreadid + ": " + thread.currentthread.threadstate.tostring());         node currentnode = openlist.removefirst();          if (currentnode == targetnode)         {             // todo: path found -> _callback             success = true;             debug.log("path found");             _callback(new pathresult(null, success, _request.callback));             return;         }          closedlist.add(currentnode);          foreach (node neighbour in currentnode.m_neighbours)         {             if (closedlist.contains(neighbour))             {                 continue;             }              int tentativeg = currentnode.m_gcost + getdistance(currentnode, neighbour);             if (openlist.contains(neighbour) && tentativeg > neighbour.m_gcost)             {                 continue;             }              neighbour.m_parent = currentnode;             neighbour.m_gcost = tentativeg;             neighbour.m_hcost = getdistance(neighbour, targetnode);              if (openlist.contains(neighbour))             {                 openlist.updateitem(neighbour);             }             else             {                 openlist.add(neighbour);             }         }     }      // todo: no path target exists -> calculate path     success = false;     debug.log("no existing path");     _callback(new pathresult(null, success, _request.callback));     return; } 

requestpath , startthreadedpathfinding in class called pathrequestmanager , findpath in other class called pathfinder.

another point threads don't stop because of error or sth still somehow running think because after started scene in unity have kill unity-process in taskmanager because sth stuck (cpu-load 80% when have that) thought deadlocks couldn't find any.

i glad if me here , if need more information source code feel free ask :)

so found problem answer in unity forums:

i working on same grid , therefore on same nodes every thread. when updating node in algorithm on 1 thread while 1 working same node bad things happend , result can seen above in question.

i solved cloning grid each thread , working on grids owned threads.