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Based on a recent customer case I would suggest to add the following tuning parameter to this section:

/etc/sysconfig/krb5kdc:
KRB5KDC_ARGS="-w "

From 'man 8 krb5kdc':

"""
The  -w  numworkers  option tells the KDC to fork numworkers processes to listen to the KDC ports and process
       requests in parallel.  The top level KDC process (whose pid is recorded in the pid file if the -P  option  is
       also  given)  acts as a supervisor.  The supervisor will relay SIGHUP signals to the worker subprocesses, and
       will terminate the worker subprocess if the it is itself terminated or if any other worker process exits.
"""

Please note,  there is already code available that auto-detects the  number of online CPUs and then sets the number of krb5kdc worker threads dynamically.  It relies on
SC_NPROCESSORS_ONLN sysconf value. But I think it's useful to have this option documented for cases where the system configuration is changed after the initial setup. This can easily happen especially in virtual environments where you can easily add or remove the number of virtual CPUs based on your requirements.

Reported by: rhn-support-tscherf

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/tuning_performance_in_identity_management/assembly_adjusting-the-performance-of-the-kdc_tuning-performance-in-idm#annotations:2da352c6-8854-4260-a028-ab20bc95fd4c

Content on the CP:

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html-single/tuning_performance_in_identity_management/index#options-controlling-the-number-of-krb5kdc-processes_assembly_adjusting-the-performance-of-the-kdc