!CHAPTER Command-Line Options for Communication 

!SUBSECTION Scheduler threads


number of scheduler threads
`--scheduler.threads arg`

An integer argument which sets the number of threads to use in the IO
scheduler. The default is 1.



!SUBSECTION Scheduler maximal queue size


maximum size of the dispatcher queue for asynchronous requests
`--scheduler.maximal-queue-size size`

Specifies the maximum *size* of the dispatcher queue for asynchronous
task execution. If the queue already contains *size* tasks, new tasks
will be rejected until other tasks are popped from the queue. Setting this
value may help preventing from running out of memory if the queue is
filled
up faster than the server can process requests.



!SUBSECTION Scheduler backend


scheduler backend
`--scheduler.backend arg`

The I/O method used by the event handler. The default (if this option is
not specified) is to try all recommended backends. This is platform
specific. See libev for further details and the meaning of select, poll
and epoll.



!SUBSECTION Io backends
`--show-io-backends`

If this option is specified, then the server will list available backends and
exit. This option is useful only when used in conjunction with the option
scheduler.backend. An integer is returned (which is platform dependent) which
indicates available backends on your platform. See libev for further details and
for the meaning of the integer returned. This describes the allowed integers for
*scheduler.backend*, see [here](#commandline-options-for-communication) for details.