malloc vs mmap in C

Question

I built two programs, one using malloc and other one using mmap. The execution time using mmap is much less than using malloc

Answer 1

I assume that you are referring to using mmap and malloc for reading data from files. In that case you pretty much got the main point:

• using fread/fwrite you have to make many calls to the OS.
• using mmap you appear to get access to the entire file in one operation. This is not entirely true because the OS probably maps the file one memory page at a time, but it is still a lot faster.