Re: [RFC} Commit 8a99b6833c88 Moves Important Real-time Settings To DebugFS

[Peter Zijlstra]

On Thu, Aug 18, 2022 at 03:53:28PM -0400, Joseph Salisbury wrote:
> Hello,
> 
> Some Ubuntu users are using the tuned package with a 5.15.x based real-time
> kernel.  Tuned adjusts various sysctl options based on a specified profile. 
> This userspace package has stopped working > 5.13 due to the following
> commit:
> 
> 8a99b6833c88 "(sched: Move SCHED_DEBUG sysctl to debugfs)"
> 
> This commit moved some important real-time sysctl knobs to debugfs in
> 5.13-rc1.  It also appears some of the sysctl options were not moved,
> sched_min_granularity_ns, for example.
> 
> I was hoping to get some feedback on how to approach this.  Would upstream
> real-time consider accepting a patch to the 5.15 real-time patch set that
> reverts this commit?  Or a new patch that adds the sysctl settings back? 
> Any other ideas or feedback would be appreciated!

None of those knobs were available when SCHED_DEBUG=n, so relying on
them is your error to begin with.

Secondly, real-time? Which if those values affects anything in
SCHED_FIFO/RR/DEADLINE ?