ARM and named man page incorrect regarding -U and number of listeners
As verified in 9.16.3 ARM. From Support ticket #16280
The ARM still says (about the options for starting named):
-U #listeners Use #listeners worker threads to listen for incoming UDP packets on each address. If not specified, named will calculate a default value based on the number of detected CPUs: 1 for 1 CPU, and the number of detected CPUs minus one for machines with more than 1 CPU. This cannot be increased to a value higher than the number of CPUs. If -n has been set to a higher value than the number of detected CPUs, then -U may be increased as high as that value, but no higher. On Windows, the number of UDP listeners is hardwired to 1 and this option has no effect.
This is in fact untrue - we're using '-n' throughout (apart from Windows), as of 9.12 and up.
E.g. from named starting up:
... 16-Apr-2020 05:51:48.172 found 24 CPUs, using 24 worker threads 16-Apr-2020 05:51:48.172 using 24 UDP listeners per interface 16-Apr-2020 05:51:48.201 using up to 21000 sockets ...
I expect this changed post-9.11 at some point when we changed how the legacy server sockets code works.
Please fix the ARM and man page appropriately (maybe in the next maintenance releases?)