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Re: [reSIProcate] DNS performance tuning

I imagine you could be running into lazy-initialization delay. I know that at least the RRCache isn't initialized until the first access is attempted. I can look through the code when I get a free moment (unless someone else knows off the top of their head). 

Best regards,
Byron Campen


Answering my own question a bit, I put new logs at the beginning of
DnsStub::query and the DnsStub::Query::Query constructor. As you would 
expect the constructor runs near instantaneously, but the delay occurs
before DnsStub::query is called, 29 ms in this case.
DEBUG | 20070122-122348.333 | dcmlaptop | SmSipMgr | RESIP:APP | 2961 | 
182419 | app.cpp:250 | ResipDns::lookup - waiting for results
+++DnsStub::query: enter 1169490228.362918
STACK | 20070122-122348.362 | dcmlaptop | SmSipMgr | RESIP:DNS | 2961 | 
158850 | dns/DnsStub.cxx:363 | Query ctor enter
STACK | 20070122-122348.363 | dcmlaptop | SmSipMgr | RESIP:DNS | 2961 | 158850 | dns/DnsStub.cxx:376 | DnsStub::Query::go: _sip._udp.flammajobby.com 
type(enum): 33 proto: 1


-----Original Message-----
From: Dave Mason
Sent: Monday, January 22, 2007 11:33 AM
To: 'Byron Campen'
Cc: resiprocate-devel@xxxxxxxxxxxxxxxxxxxx
Subject: RE: [reSIProcate] DNS performance tuning
Oops, meant to point out in my last mail that the log in DnsStub::Query::go is at the beginning of the method, so the delay has already happened before that method starts. My guess is there's some kind of overhead involved, 
which hopefully I can move or deal with.

Regards,
Dave

-----Original Message-----
From: Byron Campen [mailto:bcampen@xxxxxxxxxxxx]
Sent: Monday, January 22, 2007 11:11 AM
To: Dave Mason
Cc: resiprocate-devel@xxxxxxxxxxxxxxxxxxxx
Subject: Re: [reSIProcate] DNS performance tuning

        Well, it looks like you don't have any SRV records in your DNS,
which is what the resolver tries looking for first. When that fails, it attempts an A query. So, you're having to wait for two DNS queries to finish in sequence, which would explain some amount of delay. How much delay are 
you seeing?

Best regards,
Byron Campen


Hi,
I picked up a development build from svn last week and the RRCache
code works great, thanks for the help on that one. However, I'm still 
seeing a big delay when DnsStub::Query::go: is first called.  Is this
because I'm specifying "transport=udp"? Is there anything I can do to 
reduce or eliminate this?  I keep a DnsInterface thread running
continuously for all my lookups so I don't need to restart it each
time. I cant think of any problems with my mutex/condition that would 
prevent Query::go from starting.

Regards,
Dave

Application code
----------------
Constructor for singleton wrapper class:
   dns = new ResipDnsInterface(*stub);
   dns->run();

Lookup code:
   Lock  lock(lookupCompleteMutex);
   Condition  dnsCond;
   DebugLog (<< "ResipDns::lookup - Looking up");
   dns->lookup(res, query.uri);
   DebugLog (<< "ResipDns::lookup - waiting for results");
   dnsCond.wait(lookupCompleteMutex); // signal sent from end of
DnsHandler::handle
   InfoLog (<< "ResipDns::lookup - DNS results for " << query.uri);

Stack trace
-----------
DEBUG | 20070119-163503.126 | dcmlaptop | SmSipMgr | RESIP:APP |
17423 |
190616 | app.cpp:227 | ResipDns::lookup - Creating Uri:
sip:flammajobby.com;transport=udp
DEBUG | 20070119-163503.126 | dcmlaptop | SmSipMgr | RESIP:APP |
17423 |
190616 | app.cpp:233 | ResipDns::lookup - Creating DnsResult DEBUG |
20070119-163503.126 | dcmlaptop | SmSipMgr | RESIP:APP |
17423 |
190616 | app.cpp:236 | ResipDns::lookup - Looking up DEBUG |
20070119-163503.126 | dcmlaptop | SmSipMgr | RESIP:DNS |
17423 |
190616 | DnsResult.cxx:198 | DnsResult::lookup
sip:flammajobby.com;transport=udp STACK | 20070119-163503.126 |
dcmlaptop | SmSipMgr | RESIP:DNS |
17423 |
190616 | DnsResult.cxx:321 | Doing SRV lookup of
_sip._udp.flammajobby.com DEBUG | 20070119-163503.126 | dcmlaptop |
SmSipMgr | RESIP:APP |
17423 |
190616 | app.cpp:250 | ResipDns::lookup - waiting for results STACK |
20070119-163503.154 | dcmlaptop | SmSipMgr | RESIP:DNS |
17423 |
162926 | dns/DnsStub.cxx:375 | DnsStub::Query::go:
_sip._udp.flammajobby.com
type(enum): 33 proto: 1
STACK | 20070119-163503.155 | dcmlaptop | SmSipMgr | RESIP:DNS |
17423 |
162926 | DnsResult.cxx:912 | Received SRV result for: flammajobby.com
STACK | 20070119-163503.155 | dcmlaptop | SmSipMgr | RESIP:DNS |
17423 |
162926 | DnsResult.cxx:915 | DnsResult::onDnsResult() 0 status=4 STACK 
| 20070119-163503.155 | dcmlaptop | SmSipMgr | RESIP:DNS |
17423 |
162926 | DnsResult.cxx:978 | SRV lookup failed:
_sip._udp.flammajobby.com 4
STACK | 20070119-163503.155 | dcmlaptop | SmSipMgr | RESIP:DNS |
17423 |
162926 | DnsResult.cxx:1024 | No SRV records for flammajobby.com.
Trying A
records
STACK | 20070119-163503.155 | dcmlaptop | SmSipMgr | RESIP:DNS |
17423 |
162926 | dns/DnsStub.cxx:375 | DnsStub::Query::go: flammajobby.com
type(enum): 1 proto: 1
STACK | 20070119-163503.155 | dcmlaptop | SmSipMgr | RESIP:DNS |
17423 |
162926 | DnsResult.cxx:749 | Received dns result for: flammajobby.com
STACK | 20070119-163503.155 | dcmlaptop | SmSipMgr | RESIP:DNS |
17423 |
162926 | DnsResult.cxx:750 | DnsResult::onDnsResult() 0 STACK |
20070119-163503.155 | dcmlaptop | SmSipMgr | RESIP:DNS |
17423 |
162926 | DnsResult.cxx:771 | Adding [ V4 10.4.5.249:5060 UDP target
domain=flammajobby.com connectionId=0 ] to result set DEBUG |
20070119-163503.155 | dcmlaptop | SmSipMgr | RESIP:APP |
17423 |
162926 | app.cpp:66 | ResipDnsHandler::handle - received
flammajobby.com STACK | 20070119-163503.155 | dcmlaptop | SmSipMgr |
RESIP:DNS |
17423 |
162926 | DnsResult.cxx:178 | Returning next dns entry: [ V4
10.4.5.249:5060 UDP target domain=flammajobby.com connectionId=0 ]
DEBUG | 20070119-163503.155 | dcmlaptop | SmSipMgr | RESIP:APP |
17423 |
162926 | app.cpp:74 | flammajobby.com -> [ V4 10.4.5.249:5060 UDP
target domain=flammajobby.com connectionId=0 ] STACK |
20070119-163503.155 | dcmlaptop | SmSipMgr | RESIP:DNS |
17423 |
162926 | DnsResult.cxx:485 | Priming [] DEBUG | 20070119-163503.155 |
dcmlaptop | SmSipMgr | RESIP:APP |
17423 |
162926 | app.cpp:78 | ResipDnsHandler::handle - complete INFO |
20070119-163503.155 | dcmlaptop | SmSipMgr | RESIP:APP |
17423 |
190616 | app.cpp:253 | ResipDns::lookup - DNS results for
sip:flammajobby.com;transport=udp INFO | 20070119-163503.156 |
dcmlaptop | SmSipMgr | RESIP:APP |
17423 |
190616 | app.cpp:260 | [ V4 10.4.5.249:5060 UDP target
domain=flammajobby.com connectionId=0 ]

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