Some services might cause latency peaks when executed. At least the following services must be disabled. Depending on the Linux distribution and installed software, there might be additional services that must be also disabled.
fwupd-refresh service and timer: sudo systemctl disable fwupd-refresh.service && sudo systemctl disable fwupd-refresh.timer && sudo systemctl stop fwupd-refresh.timer
irqbalance service: sudo systemctl stop irqbalance && sudo systemctl disable irqbalance
ondemand service sets CPU governor to powersave after a while. Disable it: sudo systemctl disable ondemand
If cockpit is installed, make sure the performance monitoring is disabled.
sudo systemctl disable pmie.service
sudo systemctl disable pmie_farm.service
sudo systemctl disable pmie_check.timer
sudo systemctl disable pmie_daily.timer
sudo systemctl disable pmie_farm_check.timer
sudo systemctl stop pmie.service
sudo systemctl stop pmie_farm.service
sudo systemctl stop pmie_daily.timer
sudo systemctl stop pmie_check.timer
sudo systemctl stop pmie_farm_check.timer