Thank you for your response!
I am currently replacing the call_control module used with CDRTool Prepaid
with the dialog module using hash tables. The speed and stability are
tremendously better!
My concern is two-fold:
1) I do not want calls to be blocked because I set the hash table size too
small.
2) I do not want any memory usage problems that could cause kamailio
stability issues.
My understanding, or at least how I want to use the "hash_size" modparam,
is that hash_size gives dialog a set memory space (aka slots and buckets)
to store the dialogs being tracked. This is great since I "think" I will
have constant memory consumption that will be a fixed amount and never
"grow". However, I wanted to get a rough idea of how many dialogs
(customer calls) I could track per kamailio instance to properly choose the
hash size.
I thought it would be easy to set the value to something very small in the
lab and just run up the number of calls until kamailio hits an upper limit
and fails to create any more dialogs.
modparam("dialog", "hash_size", 32)
However, I am able to create almost 2000 dialogs no matter what size I
choose. After, reading the information in the link about hash tables and
your response, I see how a larger table with more "hashing" increases
lookup performance, but I still do not see how the total number of dialogs
that the module tracks can be set so that the kamailio memory usage is
protected. I still look at the hash_size as the key here and that there
should be a relationship, perhaps rough at best, to the maximum number of
dialogs supported in the table.
Thanks so much for your time,
Mark Blackord
Digium Cloud Services
On Sat, Dec 2, 2017 at 2:50 AM, Daniel-Constantin Mierla <miconda(a)gmail.com>
wrote:
Hello,
hash size does not set any limitation to the number of dialogs (active
calls), it has impact on searching the dialogs, so if you have a lot of
active calls, increasing the hash size might improve performances.
Effectively the hash size is used to compute the number of slots (aka
buckets) the hash table is going to have, see more technical details about
hash tables at:
-
https://en.wikipedia.org/wiki/Hash_table
Can you elaborate on your statement:
but even setting the hash size to a very tiny
number does stop me from
creating hundreds of dialogs
Do you mean you are not able to create as many dialogs as you want?
Cheers,
Daniel
On 01.12.17 19:54, Mark Blackford wrote:
Hello,
I am trying to properly size the use of the Dialog Module hash for our
implementation using:
modparam("dialog", "hash_size", <number that is power of two>)
However, in my testing, I have been unable to figure out the relationship
between the hash size and a number of dialogs I need to support. I think
the hash size is specifying a memory block in kB, but even setting the hash
size to a very tiny number does stop me from creating hundreds of dialogs.
Is there a way to determine a relationship between the hash size and a
rough number of dialogs that would be expected?
An example of a a dialog looks like this from kamctl:
[root@kamailio01 ~]# kamctl dialog show
dialog memory records
dialog:: hash=22:70
state:: 4
ref_count:: 2
timestart:: 1512151205
timeout:: 36083666
callid:: 0gQAAC8WAAACBAAALxYAAClws2wyL8GE+CSgRY7HIhmg9ZUIISZad46ntOPng3i
PIcLaxzLFaytRTI7M0Bzz0g--(a)10.155.8.40
from_uri:: sip:b53667d44239457fbc94fc2f4c4e25a6@sip.dcs-staging.net
from_tag:: 10.155.8.40+1+689d7e5e+8fcf481a
caller_contact:: sip:43f0ae1480846185e8803f21e9f2b7
21@10.155.8.40:5060;transport=udp
caller_cseq:: 24115
caller_route_set::
caller_bind_addr:: udp:10.155.8.11:5060
callee_bind_addr:: udp:10.155.8.11:5060
to_uri:: sip:2052773090@sip.dcs-staging.net
to_tag:: sip+1+bdcd0004+2038f37c
callee_contact:: sip:ca2013e84f10348a1cc825c12562bd
e7@10.155.8.40:5060;transport=udp
callee_cseq:: 0
callee_route_set::
Thanks!
--
Mark Blackford
Digium Cloud Services
678.230.8769
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www.linkedin.com/in/miconda
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Mark Blackford
Digium Cloud Services
678.230.8769