There are valid reasons for not collecting performance data at all. One of the most common reasons is on a poller, since pollers will send their check results regardless to their master, and the performance data handling will then happen at the master regardless.
Step 1: Disable performance data in Naemon
Change this parameter in /opt/monitor/etc/naemon.cfg:
Step 2: Disable and mask the NPCD service
The NPCD service is responsible for shuffling performance data, and uses the process_perfdata.pl script. You can disable this service on EL7 by running:
# systemctl disable npcd --now
# systemctl mask npcd
Created symlink from /etc/systemd/system/npcd.service to /dev/null.
This service will no longer start.
Restart Naemon and Merlin together with:
# mon restart