Can't elevate process scheduling from normal to real time (fifo), neither as a normal user or root. It's a fully updated archlinux system with the just released systemd 218. Steps to reproduce: Look for this rtkit-daemon log output, when it starts: rtkit-daemon[10832]: Successfully called chroot. rtkit-daemon[10832]: Successfully dropped privileges. rtkit-daemon[10832]: Successfully limited resources. rtkit-daemon[10832]: Running. rtkit-daemon[10832]: Canary thread running. rtkit-daemon[10832]: Failed to make ourselves RT: Operation not permitted rtkit-daemon[10832]: Watchdog thread running. downgrade to systemd 217 notice that rtkit-daemon does not outputs "Failed to make ourselves RT: Operation not permitted" anymore and any process that request real time scheduling (like jack) will now work properly.
I see the same problem on arch linux arm. Strangely if a unit is created early enough at boot time, I can get real time priority, but if it is restarted then it gets assigned to system.slice and can't get it. Can a mechanism to always force use the root slice for cpu please be returned?
Still to be seen on archlinux x86-64 with systemd 222
Please turn off RT group scheduling in your kernel. For background, please see: https://bugzilla.redhat.com/show_bug.cgi?id=1229700 and: https://github.com/systemd/systemd/pull/553
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