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Date:   Thu, 18 Aug 2022 22:31:19 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Joseph Salisbury <joseph.salisbury@canonical.com>
Cc:     linux-rt-users@vger.kernel.org, williams@redhat.com,
        bigeasy@linutronix.de, valentin.schneider@arm.com,
        linux-kernel@vger.kernel.org
Subject: Re: [RFC} Commit 8a99b6833c88 Moves Important Real-time Settings To
 DebugFS
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References: <9e6a7216-9cb9-cba4-f150-1a0eaf56353c@canonical.com>
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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 ?