Re: How deep is the xl socket queue?

From: Roger Pau Monné <roger.pau_at_citrix.com>
Date: Thu, 14 Jul 2022 13:37:46 UTC
On Wed, Jul 13, 2022 at 08:22:09PM -0700, Brian Buhrow wrote:
> 	hello.  Recently, I've started seeing messages like the following:
> sonewconn: pcb 0xfffff801074d7800 (local:/var/run/xenstored/socket): Listen queue overflow: 2
> alread
> y in queue awaiting acceptance (1 occurrences)
> 
> I figured out what causes this.  I have a number of automated scripts that use the xl
> command to do their work.  Sometimes, multiple scripts run at once, causing too many instances
> of xl to run simultaneously.  My questions are:
> What is the default queue depth for the xl socket listener?

Hm, I've got no idea TBH.  Note however this is the xenstored socket,
libxl instances are the clients here.  Can you check which version of
xenstored are you currently running?  Just paste the output of:

# ps aux |grep xenstored

Does it make any difference if you use Ocaml or C xenstored
implementations?

You can do that by changing the line in
/usr/local/etc/rc.d/xencommons:

XENSTORED=/usr/local/sbin/xenstored

Or:

XENSTORED=/usr/local/sbin/oxenstored

And rebooting (note: you must reboot the system in order to switch
between xenstored implementations).

The binary prefixed with 'o' is the Ocaml one, while the binary
without any prefix is the C one.

Thanks, Roger.