I've been playing around with a simple raytracer in go that has been working pretty neatly so far. I'm using multiple goroutines to render different parts of the image, which then place their results into a shared film.
Against my expectations, my go code is still about 3 times slower than equivalent java code. Was that to be expected? Further, when inspecting the CPU-Usage in htop, I discovered that every core is only used to about 85%. Is that an issue with htop or is there a problem with my code? Here is the cpu profile of my application
I did set GOMAXPROCS as runtime.GOMAXPROCS(runtime.NumCPU()). The full code is on github.
I would guess that garbage collector is the problem. Maybe you are making a lot of unnecessary allocations. By using runtime.ReadMemStats you can find out how much time garbage collector has been running.
If this is the case then you must find a way to reduce memory allocations. By using pools of objects for example. Look at sync.Pool. Also there are few useful links that you can find via Google that explain how to reduce memory allocation. Look at this one for example.
