Re: Lua Socket

[PA <petite.abeille@...>]

On Jul 21, 2007, at 08:21, Duck wrote:

> Well, you might be writing a "serious" server using blocking I/O and 
> multiple threads, e.g. with LuaTask, instead of using non-blocking I/O 
> and coroutines, e.g. with COPAS. (If very high concurrency is not an 
> issue, both approaches are programmatically appropriate -- different 
> strokes for different folks.)

Well... I went down the coroutine + non-blocking I/O road initially for 
an HTTP server of mine [1]... but... in practice... this doesn't really 
work for anything but demo-ware... because as soon as you start doing 
any non trivial processing per request... your server effectively start 
processing those requests serially as one cannot realistically extend 
cooperative threading across the existing tool chain (e.g. file IO is 
still blocking, etc)... so one end up with a fancy coroutine based 
server which effectively can only handle one request at the time... 
sigh... :(

My current approach [2], while not as glamourous and demo-ware friendly 
as a coroutine based one, is to outsource the entire concurrency and 
socket handling to an external host environment, D. J. Bernstein's 
tcpserver [3] in this case, while keeping all the interesting 
processing in pure Lua.

In practice, this latest approach provides a much better throughput and 
concurrency level that anything I have tried using only coroutines and 
LuaSocket.

As always, YMMV.

[1] http://dev.alt.textdrive.com/browser/LW/LWApplication.lua
[2] http://dev.alt.textdrive.com/browser/HTTP/HTTP.lua
[3] http://cr.yp.to/ucspi-tcp/tcpserver.html