Re:Intel's roadmap for Optane SSDs with 1,000x performance
by Koromix on Monday June 13, 2016 @06:15PM
(#11898184)
mmap() tricks you into thinking you can directly access the disk. What really happens when you access the mapped data is that the CPU generates a page fault, the OS takes control, copies the data from disk to physical memory and maps the page in your address space. So essentially it is a convient way to do read().
The mmap() model is good. The current page fault mechanism, not so much.
Re:Intel's roadmap for Optane SSDs with 1,000x performance
by rayiner on Monday June 13, 2016 @06:18PM
(#11898204)
The difference is that you only take the page fault once per page (or less than once if you do some prefetching in the kernel), while you have to do a system call for every read().
The mmap() model is good. The current page fault mechanism, not so much.