Lot CPU load per call while just OFFERING/RINGING state

[EiSl]

Hello Jaro,

Long time no activity from my side :)
Recently a developer asked me why sipXtapi generates so much load.
I did a quick check (on 3.2.0 stable ) and I can confirm his
observation.

In this particular use-case, sipXtapi is used to implement a call-
queue (we've removed the max-ringing time for this).
Calls are transferred to a SIP-account and do arrive as new incoming
call in sipXtapi. For a queue with e.g. 30 positions, within sipXtapi
30 accounts are created.
We only accept or reject incoming calls. A call is *never* answered,
so the call remains in the OFFERING state.

What I've observed is that every new call eats around 2% CPU load
(depends of course a bit on hardware platform).

Where is this CPU-time consumed? There is no audio and at SIP-protocol
level there is also nothing.
As you can understand... as the queue grows, the CPU usage rises and
rises and gets impact on other processes.

Do you have any idea's?
It's very easy to reproduce. You can use my ugly SimpleSipxTerm which
is in the examples. Just start this tool and have it create 6
accounts. Now from other SIP-client, make calls to these accounts (and
do not answer).
In meantime: check task-manager


With regards,
Eize