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=-2.2 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 1B27FC04A6B for ; Wed, 8 May 2019 19:15:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E0DBA216C4 for ; Wed, 8 May 2019 19:15:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Wr/ok1Fx" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727984AbfEHTPo (ORCPT ); Wed, 8 May 2019 15:15:44 -0400 Received: from merlin.infradead.org ([205.233.59.134]:52424 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727814AbfEHTPn (ORCPT ); Wed, 8 May 2019 15:15:43 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.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:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=a8FuqNzzCdRGP7Hv+sEE+t8gtRRCoRvp/IDvJa1VM5A=; b=Wr/ok1Fx8EbTh6jrvfXbYqTie /PPcvw1lKmOrlAjMUiA1ApjzWORaQnguo5S+3lAouVaq5rWan6F029KXOA38qE/cgt/XccWv0Mddt wb45sh84dIlS27Wnlb0kh4yGutHFgZnER5uAoz7Ol1Hxz9JfPFJM+Z+BYXQ+SJnJrRUjHVKilYBkt fTk0QbcS0szJKEGW6inOuzJr5QvtFuXylemC/9ufY/3WAAKKwyf6dRaIEMJBDgs5iNlDa1NhunOOj zxK3xSv1VijLavqvgHduFaPTZGrjVTagk+gnbEWX0vopzeecNtDd0nQAKUKzDv+Ryihv2HVtMuD2U qJkcB8EmA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=worktop.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1hOS2N-0003d0-Ts; Wed, 08 May 2019 19:15:32 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id 04C1798030A; Wed, 8 May 2019 21:15:29 +0200 (CEST) Date: Wed, 8 May 2019 21:15:29 +0200 From: Peter Zijlstra To: Patrick Bellasi Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, linux-api@vger.kernel.org, Ingo Molnar , Tejun Heo , "Rafael J . Wysocki" , Vincent Guittot , Viresh Kumar , Paul Turner , Quentin Perret , Dietmar Eggemann , Morten Rasmussen , Juri Lelli , Todd Kjos , Joel Fernandes , Steve Muckle , Suren Baghdasaryan Subject: Re: [PATCH v8 04/16] sched/core: uclamp: Add system default clamps Message-ID: <20190508191529.GA26813@worktop.programming.kicks-ass.net> References: <20190402104153.25404-1-patrick.bellasi@arm.com> <20190402104153.25404-5-patrick.bellasi@arm.com> <20190508190733.GC32547@worktop.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190508190733.GC32547@worktop.programming.kicks-ass.net> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 08, 2019 at 09:07:33PM +0200, Peter Zijlstra wrote: > On Tue, Apr 02, 2019 at 11:41:40AM +0100, Patrick Bellasi wrote: > > +static inline struct uclamp_se > > +uclamp_eff_get(struct task_struct *p, unsigned int clamp_id) > > +{ > > + struct uclamp_se uc_req = p->uclamp_req[clamp_id]; > > + struct uclamp_se uc_max = uclamp_default[clamp_id]; > > + > > + /* System default restrictions always apply */ > > + if (unlikely(uc_req.value > uc_max.value)) > > + return uc_max; > > + > > + return uc_req; > > +} > > + > > +static inline unsigned int > > +uclamp_eff_bucket_id(struct task_struct *p, unsigned int clamp_id) > > +{ > > + struct uclamp_se uc_eff; > > + > > + /* Task currently refcounted: use back-annotated (effective) bucket */ > > + if (p->uclamp[clamp_id].active) > > + return p->uclamp[clamp_id].bucket_id; > > + > > + uc_eff = uclamp_eff_get(p, clamp_id); > > + > > + return uc_eff.bucket_id; > > +} > > + > > +unsigned int uclamp_eff_value(struct task_struct *p, unsigned int clamp_id) > > +{ > > + struct uclamp_se uc_eff; > > + > > + /* Task currently refcounted: use back-annotated (effective) value */ > > + if (p->uclamp[clamp_id].active) > > + return p->uclamp[clamp_id].value; > > + > > + uc_eff = uclamp_eff_get(p, clamp_id); > > + > > + return uc_eff.value; > > +} > > This is 'wrong' because: > > uclamp_eff_value(p,id) := uclamp_eff(p,id).value Clearly I means to say the above does not hold with the given implementation, while the naming would suggest it does. > Which seems to suggest the uclamp_eff_*() functions want another name. > > Also, suppose the above would be true; does GCC really generate better > code for the LHS compared to the RHS?