As part of a hobby project, I'm working on a 2D game engine that will draw each pixel every frame, using a color from a palette. I am looking for a way to do that while maintaining a reasonable frame rate (60fps being the minimum). Without any game-logic in place, I am updating the values of my pixels with some value form the palette. I'm currently taking the mod of an index, to (hopefully) prevent the compiler from doing some loop-optimisation it could do with a fixed value. My very naive implementation of updating the bytes in the pixel array goes like this. On an iPhone 12 Pro, each run of updating all pixel values takes on average 43 ms, while on a simulator running on an M1 mac, it takes 15 ms. Both unacceptable, as that would leave not for any additional game logic (which would be much more operations than taking the mod of an Int). I was planning to look into Metal and set up a surface, but clearly the bottleneck here is the CPU, so if I can optimize this code, I could go for a higher-level framework. Any suggestions on a performant way to write this many bytes much, much faster (parallelisation is not an option)? struct BGRA { let blue: UInt8 let green: UInt8 let red: UInt8 let alpha: UInt8 } let BGRAPallet = [ BGRA(blue: 124, green: 124, red: 124, alpha: 0xff), BGRA(blue: 252, green: 0, red: 0, alpha: 0xff), // ... 62 more values in my code, omitting here for brevity ] private func test() { let pixelBufferPtr = UnsafeMutableBufferPointer<BGRA>.allocate(capacity: screenWidth * screenHeight) let runCount = 1000 let start = Date.now for _ in 0 ..< runCount { for index in 0 ..< pixelBufferPtr.count { pixelBufferPtr[index] = BGRAPallet[index % BGRAPallet.count] } } let elapsed = Date.now.timeIntervalSince(start) print("Average time per run: \((Int(elapsed) * 1000) / runCount) ms") }

After recording a network request using the "HTTP Traffic" instrument, I don't see the disclosure triangle documented here. I'd expect to see something similar to this screenshot: Instead, my document's top-level track is missing the disclosure triangle: I'm launching Instruments from Xcode using a debug configuration with a development certificate. I'm using an instance of URLSession directly (no third-party libraries) and am creating a URLSessionDataTask to send the request. Is this a bug in Instruments? Or am I doing something dumb? Versions Instruments Version 14.3 (14E222b) iOS Version 16.3.1 (20D67) macOS Version 13.2.1 (22D68)