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Hi everyone !I'm having a pathfinder class in a SpriteKit game on Mac that a I want to use to process every path request in the game. So I have my class stored in my SKScene and I access it from different parts of the game always from the main thread. The pathfinder uses a GKGridGraph of a pretty good size (288 x 224 nodes). The class holds an array of requests processed one after another at each update() call from the main scene. Here is the code :class PathFinder { var isLookingForPath = false var groundGraph : GKGridGraph? var queued : [PathFinderRequest] = [] var thread: DispatchQoS.QoSClass = .userInitiated func generate(minPoint: CGPoint) { // generate the groundGraph grid } func update() { // called every frame if !self.isLookingForPath { findPath() } } func findPath(from start: TuplePosition, to end: TuplePosition, on layer: PathFinderLayer, callBack: PathFinderCallback) { // Generating request let id = String.randomString(length: 5) let request = PathFinderRequest(id: id, start: start, end: end, layer: layer, callback: callBack) // Append the request object at the end of the array queued.append(request) } func findPath() { self.isLookingForPath = true guard let request = queued.first else { isLookingForPath = false return } let layer = request.layer let callback = request.callback let start = request.start let end = request.end let id = request.id var graph = self.groundGraph queued.removeFirst() let findItem = DispatchWorkItem { if let g = graph, let sn = g.node(atGridPosition: start.toVec()), let en = g.node(atGridPosition: end.toVec()) { if let path = g.findPath(from: sn, to: en) as? [GKGridGraphNode], path.count > 0 { // Here we have the path found // it worked ! } } // Once the findPath() method execution is over, // we reset the "flag" so we can call it once again from // the update() method self.isLookingForPath = false } // Execute the findPath() method in the chosen thread // asynchronously DispatchQueue.global(qos: thread).async(execute: findItem) } func drawPath(_ path: [GKGridGraphNode]) { // draw the path on the scene } }Well the code works quite good as it is. If I send random path request within (x+-10, y+-10) length it will return them to each object holding the callback in the request object pretty quickly, but suddenly one request is randomly taking a huge amount of time (approximatively 20s compared to 0.001s) and despite everything I tried I wasn't able to find out what happens. It's never on the same path, never the same caller, never after a certain amount of time... here is a video of the issue : https://www.youtube.com/watch?v=-IYlLOQgJrQIt sure happens more quickly when there is too much entities requesting but I can't figure why I'm sure it has to deal with the DispacthQueue async calls that I use to prevent the game from freezing.With delay on every call, the error appear later but is still here :DispatchQueue.global(qos: thread).asyncAfter(deadline: .now() + 0.1, execute: findItem)When I look for what is taking so much time to process it is a sub method of the GKGridGraph class :https://i.stack.imgur.com/0nZ2E.jpgSo I really don't know how to figure this out, I tried everything I could think of but it always happens whatever the delay, the number of entities, the different threads, etc...Also I couldn't reproduce the issue on a playground with approximately the same code, however in that case the execution is way longer for every calculus.Thank you for your precious help !PS : this post is on stackoverflow since a few days : https://stackoverflow.com/questions/61562600/apparently-random-execution-time-with-gkgraph-findpath-method-in-swift