[sr-dev] [Fwd: Re: [Kamailio-Users] TCP supervisor process in Kamailio]

[Andrei Pelinescu-Onciul]

On Jul 07, 2009 at 15:53, Klaus Darilion <klaus.mailinglists at pernau.at> wrote:
> Hi Andrei!
> 
> Do you think this is also relevant for sip-router's TCP implementation?


The elevated priority for tcp_main is a good idea. I'll add a config
option for it (right now there are real time prio config options, but
only for the timer processes).
The rest of the paper does not apply to sr or recent ser versions
(fd cache was implemented long time ago, tcp timers are much better,
there is no known dealdock a.s.o.).
I also don't agree with what they are trying to prove (that TCP is
comparable with UDP in terms of scalability). While there might have
been some performance problems in early TCP implementations (and there
are still a few even in sr, at least until I'll add fd sharing), you
could never make sip over TCP use so few resources as sip over UDP.
It's not only slower (due to the extra complexity in dealing with TCP
connections, both in kernel and userspace, and due to the extra parsing
needed to find SIP message boundaries on TCP), but it uses way more
resources (lots of FDs, and lots of memory).
The same could be said also for SCTP. UDP is still the best option in
terms of performance and resources used.



Andrei

> 
> -------- Original-Nachricht --------
> Betreff: Re: [Kamailio-Users] TCP supervisor process in Kamailio
> Datum: Tue, 7 Jul 2009 15:00:49 +0200
> Von: Pascal Maugeri <pascal.maugeri at gmail.com>
> An: Daniel-Constantin Mierla <miconda at gmail.com>
> CC: kamailio <users at lists.kamailio.org>
> Referenzen: 
> <990aed650907070551k594ee26cl3056fa7090742e1b at mail.gmail.com> 
> <4A53466F.1070102 at gmail.com>
> 
> On Tue, Jul 7, 2009 at 2:58 PM, Daniel-Constantin
> Mierla<miconda at gmail.com> wrote:
> >Hello,
> >
> >On 07/07/2009 02:51 PM, Pascal Maugeri wrote:
> >>
> >>Hi
> >>
> >>I recently read the following in order to optimize OpenSER in handling
> >>TCP connections:
> >>
> >>"First, the TCP supervisor process must be given an elevated priority
> >>level in order to prevent anomalous behavior due to the Linux
> >>scheduler."
> >>
> >>First of all, as this is quite old paper
> >
> >where is this paper?
> 
> http://www.cs.rice.edu/CS/Architecture/docs/ram-ispass08.pdf (Section
> 4.3, page 6).
> -pascal
> 
> 
> >
> >Thanks,
> >Daniel
> >
> >> (it refers to OpenSER 1.2),
> >>I'm wondering if such a tuning is still needed for Kamailio 1.5 branch
> >>? If yes, how can I do this ?
> >>
> >>Regards,
> >>Pascal
> >>
> >>_______________________________________________
> >>Kamailio (OpenSER) - Users mailing list
> >>Users at lists.kamailio.org
> >>http://lists.kamailio.org/cgi-bin/mailman/listinfo/users
> >>http://lists.openser-project.org/cgi-bin/mailman/listinfo/users
> >>
> >>
> >
> >--
> >Daniel-Constantin Mierla
> >http://www.asipto.com/
> >
> >
> 
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