From: Christian Borntraeger <borntraeger@de.ibm.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: peterz@infradead.org, bristot@redhat.com, bsegall@google.com,
dietmar.eggemann@arm.com, greg@kroah.com,
gregkh@linuxfoundation.org, joshdon@google.com,
juri.lelli@redhat.com, linux-kernel@vger.kernel.org,
linux@rasmusvillemoes.dk, mgorman@suse.de, mingo@kernel.org,
valentin.schneider@arm.com, vincent.guittot@linaro.org,
linux-s390@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: sched: Move SCHED_DEBUG sysctl to debugfs
Date: Tue, 27 Apr 2021 17:17:09 +0200 [thread overview]
Message-ID: <ae04549f-b009-9d90-d312-5c544f5a5e14@de.ibm.com> (raw)
In-Reply-To: <20210427110926.24f41fbb@gandalf.local.home>
On 27.04.21 17:09, Steven Rostedt wrote:
> On Tue, 27 Apr 2021 16:59:25 +0200
> Christian Borntraeger <borntraeger@de.ibm.com> wrote:
>
>> Peter,
>>
>> I just realized that we moved away sysctl tunabled to debugfs in next.
>> We have seen several cases where it was benefitial to set
>> sched_migration_cost_ns to a lower value. For example with KVM I can
>> easily get 50% more transactions with 50000 instead of 500000.
>> Until now it was possible to use tuned or /etc/sysctl.conf to set
>> these things permanently.
>>
>> Given that some people do not want to have debugfs mounted all the time
>> I would consider this a regression. The sysctl tunable was always
>> available.
>>
>> I am ok with the "informational" things being in debugfs, but not
>> the tunables. So how do we proceed here?
>
> Should there be a schedfs created?
>
> This is the reason I created the tracefs file system, was to get the
> tracing code out of debugfs, as debugfs is a catch all for everything and
> can lead to poor and insecure interfaces that people do not want to add on
> systems that they still want tracing on.
>
> Or perhaps we should add a "tunefs" for tunables that are stable interfaces
> that should not be in /proc but also not in debugfs.
Yes, a tunefs or schedfs could be considered a replacement for sysctl.
It will still break existing setups with kernel.sched* things in /etc/sysctl.conf
but at least there is a stable transition path.
next prev parent reply other threads:[~2021-04-27 15:18 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210412102001.287610138@infradead.org>
2021-04-27 14:59 ` sched: Move SCHED_DEBUG sysctl to debugfs Christian Borntraeger
2021-04-27 15:09 ` Steven Rostedt
2021-04-27 15:17 ` Christian Borntraeger [this message]
2021-04-28 8:47 ` Peter Zijlstra
2021-04-28 8:46 ` Peter Zijlstra
2021-04-28 8:54 ` Christian Borntraeger
2021-04-28 8:58 ` Christian Borntraeger
2021-04-28 9:25 ` Peter Zijlstra
2021-04-28 9:31 ` Christian Borntraeger
2021-04-28 9:42 ` Christian Borntraeger
2021-04-28 12:38 ` Peter Zijlstra
2021-04-28 14:49 ` Christian Borntraeger
2021-07-07 12:34 ` [PATCH 0/1] Improve yield (was: sched: Move SCHED_DEBUG sysctl to debugfs) Christian Borntraeger
2021-07-07 12:34 ` [PATCH 1/1] sched/fair: improve yield_to vs fairness Christian Borntraeger
2021-07-07 18:07 ` kernel test robot
2021-07-23 9:35 ` Mel Gorman
2021-07-23 12:36 ` Christian Borntraeger
2021-07-23 16:21 ` Mel Gorman
2021-07-26 18:41 ` Christian Borntraeger
2021-07-26 19:32 ` Mel Gorman
2021-07-27 6:59 ` Christian Borntraeger
2021-07-27 18:57 ` Benjamin Segall
2021-07-28 16:23 ` Christian Borntraeger
2021-08-10 8:49 ` Vincent Guittot
2021-07-27 13:29 ` Peter Zijlstra
2021-07-27 13:33 ` Peter Zijlstra
2021-07-27 14:31 ` Mel Gorman
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