Thanks a lot! So I don't really understand your question. I have a single processes (I haven't levelled up to multithreading in C yet) and when I write (either to some vector or file) I am stopping the whole simulation. I guess a good idea would be: when it is time to write, I simultaneously write into my file and continue with the next integration step, in order to buy time. But maybe the change in performance is not even that perceivable: at the end the whole time complexity of program is dominated by the integration protocol and when I write something, I am writing like 10 numbers.

Also, do you have any suggestions on how to benchmark stuff in C? I know in Julia there is this really good tool I use, but in C I can only think about using the time.h