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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 ACD31C2D0D1 for ; Thu, 19 Dec 2019 21:04:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 87D3024679 for ; Thu, 19 Dec 2019 21:04:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727205AbfLSVE0 (ORCPT ); Thu, 19 Dec 2019 16:04:26 -0500 Received: from mail.kernel.org ([198.145.29.99]:54802 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726880AbfLSVE0 (ORCPT ); Thu, 19 Dec 2019 16:04:26 -0500 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 D608D24672; Thu, 19 Dec 2019 21:04:23 +0000 (UTC) Date: Thu, 19 Dec 2019 16:04:22 -0500 From: Steven Rostedt To: Kirill Tkhai Cc: "mingo@redhat.com" , "peterz@infradead.org" , LKML , "juri.lelli@redhat.com" , "vincent.guittot@linaro.org" , "dietmar.eggemann@arm.com" , "bsegall@google.com" , Mel Gorman Subject: Re: [PATCH v3] sched: Micro optimization in pick_next_task() and in check_preempt_curr() Message-ID: <20191219160422.4eb28a2e@gandalf.local.home> In-Reply-To: <47a00e0e-69c0-2a2f-6ae1-1a8ec9b01ede@virtuozzo.com> References: <20191219113517.65617a7b@gandalf.local.home> <47a00e0e-69c0-2a2f-6ae1-1a8ec9b01ede@virtuozzo.com> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 19 Dec 2019 20:12:15 +0000 Kirill Tkhai wrote: > This introduces an optimization based on xxx_sched_class addresses > in two hot scheduler functions: pick_next_task() and check_preempt_curr(). > > It is possible to compare pointers to sched classes to check, which > of them has a higher priority, instead of current iterations using > for_each_class(). > > One more result of the patch is that size of object file becomes a little > less (excluding added BUG_ON(), which goes in __init section): > > $size kernel/sched/core.o > text data bss dec hex filename > before: 66446 18957 676 86079 1503f kernel/sched/core.o > after: 66398 18957 676 86031 1500f kernel/sched/core.o > > Signed-off-by: Kirill Tkhai Care to resend, not as a mime image? 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