Re: [PATCH v4 1/1] Documentation: real-time: Add kernel configuration guide
John Ogness <[email protected]>
| Newsgroups | dev.linux.lists.linux-rt-devel,org.kernel.vger.linux-doc,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
On 2026-07-21, Sebastian Andrzej Siewior <[email protected]> wrote: > On 2026-07-21 10:48:06 [-0400], Steven Rostedt wrote: >> On Tue, 21 Jul 2026 16:36:06 +0200 >> Sebastian Andrzej Siewior <[email protected]> wrote: >> >>>> Unfortunately, debugfs is needed to configure the fair deadline server: >>>> >>>> /sys/kernel/debug/sched/fair_server/cpu*/runtime >>> >>> So drop the reference to it. It is not "bad" to have it enabled. It is >> >> I believe that some distros feel that it is bad to enable because there's >> no real auditing of its interface. Although, it is now only accessible by >> root. > > Yeah. Either way, there shouldn't be anything real-time specific that > requires the user have it enabled or disabled. The fair deadline server is certainly real-time specific. It is the new/additional RT throttling mechanism. Generally speaking, RT systems will want to disable it or at least reduce the 50ms default. This document is not about runtime settings, but if debugfs is not enabled, the user will have no way to configure the fair deadline server at runtime. I am OK if it is completely dropped from this document. But if there are distros that think it is bad, it might be worth mentioning that this config is important (if not critical) for real-time systems. John