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@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:
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--@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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