[ircd-ratbox] DNS timeouts with kqueue on FreeBSD 5.4 + ULE scheduler

[Rachel Llorenna]

I don't know if this is a related issue, but  too have had problems
with DNS resolution under ircd on FreeBSD 4.11 (however, it might have
some features backported from the 5.x tree - there weren't such bugs
before this kernel upgrade.) It seems to affect both ircd-ratbox-2.1.2
and ircd-hybrid-7.1, so it's probably a very old bug.

I'll do some more extensive testing and provide a more detailed
report. The same issue seems to affect all my FreeBSD 4.11 servers,
although the one running Linux (presumably using RTSIGIO) doesn't seem
to have any issues. I'm pretty confident that it must be a bug in the
new kqueue implementation in BSD, but I hope that the
ircd-hybrid/ircd-ratbox developers can come up with a more permanent
workaround, since kqueue provides significant performance gain over
poll.

I've heard that ircd-hybrid-7.1 can be fixed if you recompile with a
different event interface (ie, using --enable-poll as suggested), but
I've yet to see if the same applies to ircd-ratbox.

On 6/8/05, Jeremy Chadwick <ratbox at jdc.parodius.com> wrote:
> Version:
> ircd-ratbox 2.0.8.  I have not tried 2.1.2 (contrib/ does not build
> on that version).
> 
> Description:
> This is specific to FreeBSD 5.4 (possibly 5.3 too) machines running
> kernels build with the SCHED_ULE scheduler (vs. the older SCHED_4BSD
> scheduler, and using ratbox with the kqueue I/O event driver.
> 
> My guess is that the ratbox kqueue code is "broken" in some way;
> ULE has changed pretty significantly between 5.2 and 5.4, so it
> wouldn't surprise me.
> 
> I can confirm that other kqueue applications on 5.4 (such as Apache 2.0
> with kqueue patches, BIND 9, and MySQL 4.1) all work without problems,
> 
> I can provide a machine for testing+debugging, although Lee should
> already have access to it.  :-)  Drop me a note if you need your passwd
> reset, Lee...
> 
> Workaround:
> Disable kqueue support by using --enable-poll.
> 
> --
> | Jeremy Chadwick                                 jdc at parodius.com |
> | Parodius Networking                        http://www.parodius.com/ |
> | UNIX Systems Administrator                   Mountain View, CA, USA |
> | Making life hard for others since 1977.                             |
> 
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> 


-- 
Regards,

Rachel Llorenna (frequency)