An ACM in a 180? On Thu, 9 Apr 2020 at 21:37, Luis Rojas G. <[email protected]> wrote:
> Hello, Daniel, > > Yes, yes, yes, you are right. I got confused for a moment. Yes, the > criteria for dispatcher is only for the request. And so, it will have no > effect on the replies. On the replies only the via headers are considered. > Wel, moving to round robin increased the throughput for a single instance. > Now it can process over 1000 CAPS. > > For the scenario ack-reinvite, the solution adding a small delay for > re-invite, using something like async_ms_sleep() will solve it, so I am not > worried ( I mentioned on a previous post that I have seen also that > scenario happening with this operator. Re-invite immediately after ACK, and > it caused us problems) > > My problem is still 180-200. it will not matter the number of processes > or cores. In the end, it's a classical multi-process/multi-threaded race > condition. Considering the architecture of Kamailio, with multiple > processes, the problem will appear. And the more the traffic, the more > close in time 180 and 200 are, the more it will happen. With my currents > test, with 180 and 200 very close, I am getting around 0.5% of cases > suffering from that condition. > > I know, if you think in "only SIP", yes, it's not so important the 180. > it's important in my case, because my customer is very complicated, and > they will not like to see messages coming to our platform in one order and > going out in other. > And the second : it's not only SIP. they usually have interworking, and > 180 then will carry an ISUP ACM body that is important. As I mentioned in a > previous post, for instance, the Backward Call Indicators, with very > important subfields like the Charge Indicator. > > I understand. It's UDP. Messages can be lost on the network. OK. Messages > can arrive out of order. OK. But i't s pity that if messages were not lost > and arrived in order, they leave kamailio out of order. > > So far the only solution I see is to try to insert a small delay before > forwarding the 200. > > Best rgards, > > Luis > > > > On 4/9/20 3:58 PM, Daniel-Constantin Mierla wrote: > > > [email protected] appears similar to someone who previously sent you > email, but may not be that person. Learn why this could be a risk > <http://aka.ms/LearnAboutSenderIdentification> > Feedback <http://aka.ms/SafetyTipsFeedback> > > Hello, > > dispatcher has nothing to do with handling sip replies. It is intended > only for routing sip requests. If you use dispatcher for replies, you do it > wrong, just let kamailio route them based on Via headers. > > So maybe I was looking at the wrong message flow processing, I was > speaking mainly about the case when the caller sends quickly the reINVITE > after the ACK to the initial INVITE 200ok and the reINVITE gets to callee > before the ACK. That was more of a branching in discussion on Alex' remarks > and the situation that I enocountered in the past and created troubles. > Never had to deal with troubles caused by change of order between 180 and > 200. In IP world, if the time between 180 and 200 is very short, it doesn't > matter at all, because the 180 is for start play a ring tone, which a human > may not even hear it when 200 comes 50ms after it. > > If you face the re-ordering for replies, then Kamailio doesn't do much > internally if you don't have reply_route{} (as well as no onsend_route) in > config file, provided that you do not use tm module for sending out (and by > that no onreply_route or failure_route). > > For a sip reply, kamilio is parsing the headers to find the 2nd Via header > and use that address to send out the reply. The request route is not > executed for sip replies. > > What you can try is to set number of kamailio processes not to exceed the > number of CPU cores, so there is "no real competition" to get CPU cycles. > It could improve a bit, but still not a 100% accuracy (ie., there are other > processes running on the system). > > Cheers, > Daniel > On 09.04.20 21:29, Luis Rojas G. wrote: > > 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: > > > [email protected] appears similar to someone who previously sent you > email, but may not be that person. Learn why this could be a risk > <http://aka.ms/LearnAboutSenderIdentification> > Feedback <http://aka.ms/SafetyTipsFeedback> > > 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 > SixbellLos Leones 1200 > Providencia > Santiago, Chile > <https://www.google.com/maps/search/Los+Leones+1200%0AProvidencia%0ASantiago,+Chile?entry=gmail&source=g> > Phone: (+56-2) 22001288mailto:[email protected] > <[email protected]>http://www.sixbell.com > <https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.sixbell.com%2F&data=02%7C01%7C%7Cdc7f541ef3c74e85e61008d7dcc0562d%7Cab4a33c2b5614f798601bc921698ad08%7C0%7C0%7C637220590981766356&sdata=D2B0niyYm9fstMXOG9b%2BMzlbc3pZmt72mkL3PPPy7kY%3D&reserved=0> > > -- > Daniel-Constantin Mierla -- www.asipto.com > <https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.asipto.com%2F&data=02%7C01%7C%7Cdc7f541ef3c74e85e61008d7dcc0562d%7Cab4a33c2b5614f798601bc921698ad08%7C0%7C0%7C637220590981766356&sdata=DO4yFB3gccT5ZXuv37oOLIri%2BF5jTnA4kHQaIjV0YbQ%3D&reserved=0>www.twitter.com/miconda > > <https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.twitter.com%2Fmiconda&data=02%7C01%7C%7Cdc7f541ef3c74e85e61008d7dcc0562d%7Cab4a33c2b5614f798601bc921698ad08%7C0%7C0%7C637220590981776349&sdata=x%2BMcm9Dv%2FGY4fg54k6EbQIwHyeAMe4Y6hZrNCfOG4Q4%3D&reserved=0> > -- www.linkedin.com/in/miconda > <https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.linkedin.com%2Fin%2Fmiconda&data=02%7C01%7C%7Cdc7f541ef3c74e85e61008d7dcc0562d%7Cab4a33c2b5614f798601bc921698ad08%7C0%7C0%7C637220590981786347&sdata=b86Wa3h84oy0BcVl6pLOqLwgi4Fssya2re7Y1GOiEd4%3D&reserved=0> > > > -- > Luis Rojas > Software Architect > SixbellLos Leones 1200 > Providencia > Santiago, Chile > <https://www.google.com/maps/search/Los+Leones+1200%0AProvidencia%0ASantiago,+Chile?entry=gmail&source=g> > Phone: (+56-2) 22001288mailto:[email protected] > <[email protected]>http://www.sixbell.com > > _______________________________________________ > Kamailio (SER) - Users Mailing List > [email protected] > https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users > -- Regards, David Villasmil email: [email protected] phone: +34669448337
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