The point is mmap is good for read heavy workload and they do go into a test setup where they compare performance between mmap and a file based io system. Bandw

The point is mmap is good for read heavy workload and they do go into a test setup where they compare performance between mmap and a file based io system. Bandwidth seems to fall after the page cache fills up. Anyways it's not like OS will do some magic one a page needs to be flushed to disc. It all depends on how quickly and how nicely scheduling is done. Paper also goes into software aspects of using an mmap system. 3.2 and 3.4 seem quite relevant software problems.