What were you trying to do that didn't work?

Set the real-time profile for RHEL for realtime. Note that it is currently broken: See https://issues.redhat.com/browse/RHEL-52430

Rating this as critical because it means customers can not run RHEL 9.0 for realtime with the realtime tuned profile and I can not get crash dumps of the real-time kernel for RHEL 9.0 for debugging. The realtime tuned profile is our listed preferred way to run as written in our customer facing documentation.

How reproducible:

After you restart you may need to restart again or use a grubby command to trigger it such as `grubby add crashkernel=512M`. You can see this by press e on the grub boot screen.

Steps to reproduce

1. Install tuned-profiles-realtime
2. Amend /etc/tuned/realtime-variables.conf by adding 

   isolated_cores=${f:calc_isolated_cores:1}

1. Set profile to realtime: `sudo tuned-adm profile realtime`
2. Restart, grub should report a syntax error when it tries to boot a kernel as shown below

Expected results

See this picture from 9.2

Actual results the isolcpus is not expanded (Press e on grub to show)