[web-devel] maxListenQueue

Kazu Yamamoto ( 山本和彦 ) kazu at iij.ad.jp
Wed Oct 10 08:47:15 CEST 2012

Hello guys,

One guy experienced that warp refuses connections when many
connections come. He pointed out that it is due to the listen queue.
Network.Socket.maxListenQueue is typically 128 since SOMAXCONN is set
to 128 in sys/socket.h. So, even if we increase kern.ipc.somaxconn by
"sysctl", servers using "listenOn" cannot make use of it.

If my understanding is correct, it is safe to specify a large backlog
number to listen(). For instance, we can specify 2,000 even if
kern.ipc.somaxconn is 128.

Q1) I think that the name of maxListenQueue is misleading. What do you
    think? If people also feel misleading, how to fix it? Is
    documentation good enough?

Q2) listenOn uses maxListenQueue. Should we fix it by specifying a
    large backlog number? If we don't want to change it, should we
    document well?


warp relies on network-conduit which uses maxListenQueue. I will fix
this anyway.


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