Hello,
I just realized that I had the dispatcher configured using a hash of
Call-ID. That means, after recvfrom there must be an extra processing
finding the Call-ID header in message, to calculate a hash and then
forward() message. The more the processing, the more cases when 200
could arrive before 180. I just changed it to round robin, and the
amount decreased a lot, but it's still there. If I send a burst of 1000
messages, about 5 of them leave out of order every time.
Best regards,
Luis
On 4/9/20 1:48 PM, Luis Rojas G. wrote:
Hello,
I have a lot of experience developing mutithreaded applications, and I
don't see it so unlikely at all that a process loses cpu just after
recvfrom(). It's just as probable as to lose it just before, or when
writing on a cache or just before of after sendto(). If there are many
messages going through, some of them will fall in this scenario. if I
try sending a burst of 100 messages, I see two or three presenting the
scenario.
Just forward() with a single process does not give the capacity. I'm
getting almost 1000caps. More than that and start getting errores,
retransmissions, etc. And this is just one way. I need to receive the
call to go back to the network (our application is a B2BUA), so I will
be down to 500caps, with a simple scenario, with no reliable
responses, reinvites, updates, etc. I will end up having as many
standalone kamailio processes as the current servers I do have now.
I really think the simplest way would be to add a small delay to 200
OK. Very small, like 10ms, should be enough. Simple and it should
work. As Alex Balashov commented he did for the case with ACK-Re-Invite.
I have to figure out how to make async_ms_sleep() work in reply_route().
Thanks for all the comments and ideas
Best regards,
Luis
. On 4/9/20 12:17 PM, Daniel-Constantin Mierla wrote:
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Hello,
then the overtaking is in between reading from the socket and getting
to parsing the call-id value -- the cpu is lost by first reader after
recvfrom() and the second process get enough cpu time to go ahead
further. I haven't encountered this case, but as I said previously,
it is very unlikely, but still possible. I added the route_locks_size
because in the past I had cases when processing of some messages took
longer executing config (e.g., due to authentication, accounting, ..)
and I needed to be sure they are processed in the order they enter
config execution.
Then the option is to see if a single process with stateless sending
out (using forward()) gives the capacity, if you don't do any other
complex processing. Or if you do more complex processing, use a
dispatcher process with forwarding to local host or in a similar
manner try to use mqueue+rtimer for dispatching using shared memory
queues.
Of course, it is open source and there is also the C coding way, to
add a synchronizing mechanism to protect against parallel execution
of the code from recvfrom() till call-id lock is acquired.
Cheers,
Daniel
--
Luis Rojas
Software Architect
Sixbell
Los Leones 1200
Providencia
Santiago, Chile
Phone: (+56-2) 22001288
mailto:[email protected]
http://www.sixbell.com
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