Andres Freund <andres(at)anarazel(dot)de> writes:
> I'm somewhat against this patch, as it's fairly fundamentally incompatible
> with AIO. There's no real way to get information in this manner if the IO
> isn't executed synchronously in process context...
Even without looking ahead to AIO, there's bgwriter, walwriter, and
checkpointer processes that all take I/O load away from foreground
processes. I don't really believe that this will produce useful
numbers.
regards, tom lane