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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 E8A98C433F5 for ; Tue, 14 Sep 2021 11:32:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C632360C40 for ; Tue, 14 Sep 2021 11:32:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232043AbhINLdT (ORCPT ); Tue, 14 Sep 2021 07:33:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52400 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231941AbhINLdR (ORCPT ); Tue, 14 Sep 2021 07:33:17 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2FFD0C061574 for ; Tue, 14 Sep 2021 04:32:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=FsfKK5Kf9vKOxvR+9nsUJsi/c2UPNx/XksUYhPIZxzQ=; b=tbYyq0WkHL9L6+6fcr/8s9zv7m FtDypcaSf0fRrxiR7uf3Snls2idNGwX9ErS/e0NlJeGHeC7a+gwkac2Z3ZimK4BSVm7NDdB8BanUT CfGlGObVwO29buR3dsqrqVjLupweO/ib4f9EMeZI5Zc9fsqyFj9ZDo0kbGUWa2fhMdXi0XrH40Vdl H9RvwtD2CNeDpTtlQih8oMEeeJ8nG/XhwxeGUP9NThATLhIewHghYw/58edZk9ciY74Asl+ixPkA4 wtHB25S38nccETWBDtl75G/OhnOP8OggfCzYWqDXjkYnjAItzLIYqDf3szJYH+aaPbcyW3gFyjYlk kJgJVNHw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1mQ6df-00EbX3-Nz; Tue, 14 Sep 2021 11:30:24 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id CFED3300255; Tue, 14 Sep 2021 13:30:09 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id A4DBE20CB3026; Tue, 14 Sep 2021 13:30:09 +0200 (CEST) Date: Tue, 14 Sep 2021 13:30:09 +0200 From: Peter Zijlstra To: Yicong Yang Cc: mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, 21cnbao@gmail.com, Linux Kernel Mailing List , "Song Bao Hua (Barry Song)" , prime.zeng@huawei.com, "guodong.xu@linaro.org" Subject: Re: [RFC] Perfomance varies according to sysctl_sched_migration_cost Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 14, 2021 at 03:27:09PM +0800, Yicong Yang wrote: > 2. The ABI now has been removed from sysctl and moved to debugfs. As tuning this can improve the performance > of some workloads on some platforms, maybe it's better to make it a formal sysctl again with docs? It never was an ABI, there is nothing to restore. It has always been CONFIG_SCHED_DEBUG. I'm open to topology based improvements to the code, but I don't think user tunables are a good way.