[asterisk-dev] Suspected deadlocks in Asterisk 1.8 under heavy load

[Tony Mountifield]

In article <4E4B2634.6090602 at digium.com>,
Kevin P. Fleming <kpfleming at digium.com> wrote:
> On 08/16/2011 06:42 PM, Alistair Cunningham wrote:
> > Just to let everyone know, we strongly suspect that Asterisk 1.8.4.4 and
> > 1.8.5.0 suffer from occasional deadlocks under heavy load, possibly
> > related to the local channel. The symptoms seem to vary, but include:
> >
> > 1. Asterisk stops responding to SIP packets, but the Asterisk console
> > and manager interface remain responsive. A "sipsak -s sip:127.0.0.1:5060
> > -d" times out.
> 
> Matt Nicholson committed a change to the 1.8, 10 and trunk branches 
> today to solve a significant performance issue caused by the change to 
> chan_sip to return the SIP hangup cause to the 'master' channel. His 
> change made that behavior optional, even though it was already released 
> in 1.8, because of the performance impact it has. We had another 
> customer report a similar set of symptoms.

Surely something that just consumes a significant amount of CPU shouldn't
cause a deadlock directly? A deadlock indicates a logic error. Of course,
the extra load might make the window longer for a potential deadlock to occur,
but this might even aid in reproducing it and tracking it down...

Cheers
Tony
-- 
Tony Mountifield
Work: tony at softins.co.uk - http://www.softins.co.uk
Play: tony at mountifield.org - http://tony.mountifield.org