I am profiling my app (built with Codename One) using Xcode and an iPhone X device. I notice that, during heavy calculations (single- or multithreaded), sigprocmask and __sigaltstack (from libsystem_kernel.dylib) are the biggest time consumers with more than 20% each. That is a huge overhead. Does anyone know where this is coming from and if there is a way to reduce the overhead?
Not a huge expert on these but as far as I can tell they're low level kernel calls. I think both of these are profiler overhead so they won't be the top of the list if you run without a profiler.
Again, not an expert but this makes sense. The profiler needs to find out stuff about the current method and stack periodically.