asterisk users - Aug 2004 - SOLVED: 100% cpu usage causes big problems

For the last couple of days I have been battling a * installation (company
PBX) that has been spinning on the cpu at 100% utilization. This was
causing dropped calls, horrible SIP call quality, etc. The box is running
the CVS * as of Aug 5 on Fedora Core 1 on an AMD Duron processor. I called
Digium and had them look into it (I was told they might be interested
since it has been a long standing irreproducable problem, I have a Zap
board in the system as well) and they logged into the system, ran gdb on
the * process, etc. and were unable to come up with anything. After
banging my head on this for hours and hours I happened to mention my
current problem on IRC and someone (Blade`) said he had run into the exact
same thing. He suggested I edit /etc/asterisk/modules.conf and uncomment
this line:

noload => chan_oss.so

I uncommented the line causing the chan_oss.so module to not load and
suddenly the cpu utilization problem was solved and everything runs
smoothly. It would seem this module interacts quite badly with the
installed sound card which is a:

Silicon Integrated Systems [SiS] SiS PCI Audio Accelerator (rev 2)

I also noticed on the * console during startup and in the logfile (but
never paid much attention to it because it didn't seem important at the
time) the following error messages:

XXX I don't work right with non-full duplex sound cards XXX
Read error on sound device: Resource temporarily unavailable
Ignoring port for now

I also saw the following messages in the logfile:

Request to schedule in the past?!?!

The first set of messages were because the sound card wasn't up to snuff
and the second is because the sound card was causing the chan_oss module
to spin sucking up all of the cpu which caused it to fall behind in
keeping up with VOIP streams which causes the "Request to schedule in the
past" error. 

I have also added this bit of into to the wiki. I originally searched the
wiki for the "Request to schedule in the past" error message which
took me
to this page:

http://www.voip-info.org/tiki-index.php?page=Asterisk+Request+to+schedule+in+the+past

so that is where I have added my findings on this problem so that others
don't have to go through what I went through.

-- 
Tracy Reed                     The attachment is a digital signature.
http://copilotconsulting.com   More info: http://copilotconsulting.com/sig
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