chrt operation not permitted


I am attempting to set real time priorities on an application which is started on boot using systemd via chrt -p 99 XXXX where XXXX=pid number. I get the response “operation not permitted” and I’m not sure why. Have two Pis running DietPi and this works just fine but on my Sparky it does not. I’ve confirmed with another Sparky owner (who runs DietPi) that this functions correctly for him.

Any help would be appreciated.

I’m still messing around with this. One odd thing I’ve noticed which may be related. I use putty to ssh into my dietpi machines from windows. When I ssh into the sparky (on which thread priorities are not working) in the upper left corner of putty the connection is listed as root@sparky (sparky being the hostname) when I ssh into the pi’s the connection is just listed as the hostname though I sign in as root on all three.

As I understand chrt and any rtprio are pretty locked down to non-root users. I wonder if somehow I managed to make my root account on the sparky not actually the root user. On the other hand both the sparky and the pi’s all list the same users and entering sudo su on my sparky does not then allow me to set priorities via chrt.