oh, and unless you do stuff like...
for (foo = somestring; strlen(foo) > 0); foo++)
or some weird lots of DB-queries
I wouldn't expect anything below ----2 to be byound of the threshhold _one_ user could notice; this just all gets important once you want to serve lots of users.
however, the async approach isn't about making something slower to the user; its primarily about using the cpu more effectively while waiting for the IO to that user.
in fact this makes stuff even faster to the user in some cases;
i.e. i3wm.org uses libev + XCB to manage its conversation with the X11 server; which makes it in fact lots faster than other windowmanagers around;
these other windowmanagers will send a resize directive to the X11 server and wait for its reply to continue their command flow; while i3wm uses XCB to serialize the X11 command (which is somewhat like CORBA just to name a comparison) and send it plus using libev to wait for the reply; it then can continue doing other stuff [using XCB to send more requests...) without having to wait for the first command to continue; once the reply is there, XCB deserialises that status sent by the X-server and continues this control flow and commands basing on the results of that command.
think of it as "multiplexing" the cpu since the cpu to file i/o since is lots faster (see table of last post).
If you still have doubts of asyncio having negative impact on performance to the end-user, please let me know.
