From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8B616C43461 for ; Tue, 27 Apr 2021 15:09:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5EDF7613C1 for ; Tue, 27 Apr 2021 15:09:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238691AbhD0PKO (ORCPT ); Tue, 27 Apr 2021 11:10:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:40856 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235466AbhD0PKN (ORCPT ); Tue, 27 Apr 2021 11:10:13 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 796A9613E2; Tue, 27 Apr 2021 15:09:28 +0000 (UTC) Date: Tue, 27 Apr 2021 11:09:26 -0400 From: Steven Rostedt To: Christian Borntraeger 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 Message-ID: <20210427110926.24f41fbb@gandalf.local.home> In-Reply-To: <20210427145925.5246-1-borntraeger@de.ibm.com> References: <20210412102001.287610138@infradead.org> <20210427145925.5246-1-borntraeger@de.ibm.com> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 27 Apr 2021 16:59:25 +0200 Christian Borntraeger 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. -- Steve