Re: [9fans] Nagle algorithm

[David Gordon Hogan <dhog@plan9.bell-labs.com>]

> > That makes sense, thanks. Not a problem for my application, but it's good
> > to be aware of a potential problem.
>
> (It should be noted that the same thing proved true of X applications;
> Nagle isn't just bad for Plan 9 RPC's; it's bad for *any* RPC
> application.)

Sorry to quibble...  technically, the X protocol isn't an RPC
protocol.  Events and errors are asynchronous; many of
the requests do not require a response.  There are some
so-called ``round trip requests'' which is where the RPC
behaviour comes in.

One such request is the one that fetches a property from
a window; this accounts for the often excrutiatingly slow
startup times for X applications, which have to communicate
with the window manager through a whole slew of XGetProperty
requests and their ilk.  Motif is particularly bad in this regard: the
ICCCM wasn't complex enough for them, they added more
properties, which basically only MWM knows about.

But, anyway, X was deliberately engineered to be as
insensitive to round trip delays as the designers thought
possible, by the liberal use of its asynchronous model.  Plan
9 achieves much the same effect by allowing multiple draw(3)
requests to be sent in a single write.  They are buffered up by
the draw library.  I run rio and acme over my cpu or drawterm
connection from home; they are quite snappy.