Vincent Sweeney wrote: > > > [I want to use Linux for my irc server, but performance sucks.] > > > 1) Someone is going to have to recode the ircd source we use and > > > possibly a modified kernel in the *hope* that performance improves. > > > 2) Convert the box to FreeBSD which seems to have a better poll() > > > implementation, and where I could support 8K clients easily as other > > > admins on my chat network do already.... > > > > No need to use a modified kernel; plain old 2.4.18 or so should do > > fine, it supports the rtsig stuff. But yeah, you may want to > > see if the core of ircd can be recoded. Can you give me the URL > > for the source of the version you use? I can peek at it. > > It only took me two days to recode betaftpd to use Poller... > > http://dev-com.b2irc.net/ : Undernet's IRCD + Lain 1.1.2 patch
Hmm. Have a look at http://www.mail-archive.com/coder-com@undernet.org/msg00060.html It looks like the mainline Undernet ircd was rewritten around May 2001 to support high efficiency techniques like /dev/poll and kqueue. The source you pointed to is way behind Undernet's current sources. Undernet's ircd has engine_{select,poll,devpoll,kqueue}.c, but not yet an engine_rtsig.c, as far as I know. If you want ircd to handle zillions of simultaneous connections on a stock 2.4 Linux kernel, rtsignals are the way to go at the moment. What's needed is to write ircd's engine_rtsig.c, and modify ircd's os_linux.c to notice EWOULDBLOCK return values and feed them to engine_rtsig.c (that's the icky part about the way linux currently does this kind of event notification - signals are used for 'I'm ready now', but return values from I/O functions are where you learn 'I'm no longer ready'). So I dunno if I'm going to go ahead and do that myself, but at least I've scoped out the situation. Before I did any work, I'd measure CPU usage under a simulated load of 2000 clients, just to verify that poll() was indeed a bottleneck (ok, can't imagine it not being a bottleneck, but it's nice to have a baseline to compare the improved version against). - Dan
