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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 09A1AC433ED for ; Wed, 7 Apr 2021 12:57:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C6BB46124B for ; Wed, 7 Apr 2021 12:57:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352503AbhDGM5s (ORCPT ); Wed, 7 Apr 2021 08:57:48 -0400 Received: from foss.arm.com ([217.140.110.172]:56862 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235427AbhDGM5j (ORCPT ); Wed, 7 Apr 2021 08:57:39 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8BFEF1063; Wed, 7 Apr 2021 05:57:29 -0700 (PDT) Received: from e113632-lin (e113632-lin.cambridge.arm.com [10.1.194.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 047493F792; Wed, 7 Apr 2021 05:57:27 -0700 (PDT) From: Valentin Schneider To: Peter Zijlstra Cc: mingo@kernel.org, mgorman@suse.de, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, bristot@redhat.com, joshdon@google.com, linux-kernel@vger.kernel.org, greg@kroah.com Subject: Re: [PATCH 4/9] sched: Move SCHED_DEBUG to debugfs In-Reply-To: References: <20210326103352.603456266@infradead.org> <20210326103935.025550243@infradead.org> <87blaqnzho.mognet@arm.com> Date: Wed, 07 Apr 2021 13:57:22 +0100 Message-ID: <878s5untfx.mognet@arm.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/04/21 14:26, Peter Zijlstra wrote: > On Wed, Apr 07, 2021 at 11:46:43AM +0100, Valentin Schneider wrote: >> I can't find the threads in a hurry, but ISTR justifications for keeping >> this around were: >> - Most distros have CONFIG_SCHED_DEBUG=y because knobs and ponies >> - Topology debug prints are "too verbose" > > ^^ that mostly. > >> - NUMA distance matrix processing gets slower >> >> If we make it so distros stop / don't need to select CONFIG_SCHED_DEBUG, > > We're not there yet, I think :-( > Yeah, I know, a man can dream... At least now I can make use of CMDLINE_EXTEND on arm64. >> then I don't think the above really stands anymore (also, sched_init_numa() >> now has the same complexity regardless of sched_debug), and we could keep >> everything under CONFIG_SCHED_DEBUG. > > But yes, the reason this knob exists is ebcause I too frequently forget > to add the boot time knob, so I added this one to enable it at runtime > and then I get topology prints when I hotplug cycle a cpu.