David Carlin created TS-2524:
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             Summary: Reevaluate default proxy.config.net.listen_backlog
                 Key: TS-2524
                 URL: https://issues.apache.org/jira/browse/TS-2524
             Project: Traffic Server
          Issue Type: Bug
          Components: Network
            Reporter: David Carlin


Leif mentioned in TS-2395 that he was having some problems related to 
proxy.config.net.listen_backlog.

According to this article:

http://blog.dubbelboer.com/2012/04/09/syn-cookies.html

the kernel takes the backlog value, adds 1 and rounds up to the nearest power 
of 2.  It sets max queue length to the log2 value of this number.

This is why backlog of 511 results in max queue length of 9 (what you want) 
where as setting backlog to 512 expecting a max queue length of 9 you end up 
with 10.

The above article mentions that nginx and apache set a default backlog of 511.

We have a systemtap script that shows current queue length and max queue 
length, I never see a max queue length greater than 15 (32768 connections) even 
when I set proxy.config.net.listen_backlog to 2^16 or 2^16 -1 so not sure why 
2^16-1 made a difference for you.  Isn't this value in records config of type 
INT (signed) so it can't be more than 2^15 anyways?



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