IRC, freenode, #hurd, 2011-07-22
<braunr> an interesting question i've had in mind for a few weeks now is I/O accounting <braunr> what *is* I/O on a microkernel based system ? <braunr> can any cross address space transfer be classified as I/O ?
IRC, freenode, #hurd, 2011-07-29
< braunr> how does the hurd account I/O ? < youpi> I don't think it does < youpi> not an easy task, actually < youpi> since gnumach has no idea about it < braunr> yes < braunr> another centralization issue < braunr> does network access count as I/O on linux ? < youpi> no < braunr> not even nfs ? < youpi> else you'd get 100% for servers :) < braunr> right < youpi> nfs goes through vfs first < braunr> i'll rephrase my question < youpi> I'd need to check but I believe it can check nfs < braunr> does I/O accounting occur at the vfs level or block layer ? < youpi> I don't know, but I beleive vfs < youpi> (at least that's how I'd do it) < braunr> i don't have any more nfs box to test that :/ < braunr> personally i'd do it at the block layer :) < youpi> well, both < youpi> so e2fsck can show up too < braunr> yes < youpi> it's just a matter of ref counting < youpi> apparently nfs doesn't account < youpi> find . -printf "" doesn't show up in waitio < braunr> good < youpi> well, depends on the point of view < youpi> as a user, you'd like to know whether your processes are stuck on i/o (be it disk or net) < braunr> this implies clearly defining what io is