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=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,PLING_QUERY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 681B9C3A5A1 for ; Sun, 25 Aug 2019 21:20:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 43CAD20674 for ; Sun, 25 Aug 2019 21:20:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729074AbfHYVTi (ORCPT ); Sun, 25 Aug 2019 17:19:38 -0400 Received: from mail-lj1-f194.google.com ([209.85.208.194]:44901 "EHLO mail-lj1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728944AbfHYVTh (ORCPT ); Sun, 25 Aug 2019 17:19:37 -0400 Received: by mail-lj1-f194.google.com with SMTP id e24so13244339ljg.11 for ; Sun, 25 Aug 2019 14:19:36 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:from:to:cc:references:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=XAGbIDdFga1X2HlsM3DdDuO+5VUileKxN3AsXn36/xY=; b=PdlCHmffCCrSZO/JGd1pD4URjz/3MmNUpLc6+6cifx0wYNMMnIc4ihsxv6wmWfxs+N Zam7b7QA6yeDZtjWyUvyI/kklrcm+HF00dzCnrT6eECoPwiDTIbgZLcbL2M4euUuLSNU 01j8zxJ91qhvyobvma2SSYWxHXIdVbEU15arTjN85+6+mfTiCtH5JVm5lfUIZJlS3BHh 50ThOoqpoLT44CWYCoiXA0H2ZRgCHdvkmphZ57kkmTcpimARzWFqNmcFltYKjDTr8pXl +KT5I/1k/QuzC5P+seofYK/OEQf9Z/VvqY1l2DjjSG7HdtRwplTu1PIt4a0ElDj2x7BL dm+Q== X-Gm-Message-State: APjAAAV2AR/txDOUZ5CqUNg1HM9vcONsSxcwtV+ouRxvzS3x02KolVNt 9ODdVE631VCfQJutaMKzngMdwOX4 X-Google-Smtp-Source: APXvYqy8P4V6TzHzyfGdKLQHZ8Clh8NRX1pSFmfp2r760J2XBalgrBjfT6OhBC7Fdns2DUts2xzEQQ== X-Received: by 2002:a2e:875a:: with SMTP id q26mr8656162ljj.107.1566767975775; Sun, 25 Aug 2019 14:19:35 -0700 (PDT) Received: from [10.68.32.192] (broadband-188-32-48-208.ip.moscow.rt.ru. [188.32.48.208]) by smtp.gmail.com with ESMTPSA id f28sm1516386lfp.28.2019.08.25.14.19.35 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 25 Aug 2019 14:19:35 -0700 (PDT) Subject: Re: [PATCH] scripts: coccinelle: check for !(un)?likely usage From: Denis Efremov To: Joe Perches , cocci@systeme.lip6.fr Cc: linux-kernel@vger.kernel.org, Julia Lawall , Gilles Muller , Nicolas Palix , Michal Marek References: <20190825130536.14683-1-efremov@linux.com> <88f6e48e-1230-9488-a973-397f4e6dfbb5@linux.com> Message-ID: <25032fea-bda4-a491-def3-05bb5f569875@linux.com> Date: Mon, 26 Aug 2019 00:19:34 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <88f6e48e-1230-9488-a973-397f4e6dfbb5@linux.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > I think it's incorrect to say so in general. For example, on x86/64: > > $ make mrproper > $ make allyesconfig > $ make && mv vmlinux vmlinux-000 > $ make coccicheck MODE=patch COCCI=scripts/coccinelle/misc/unlikely.cocci | patch -p1 > $ make > $ ./scripts/bloat-o-meter ./vmlinux-000 ./vmlinux > add/remove: 0/0 grow/shrink: 3/4 up/down: 41/-35 (6) > Function old new delta > dpaa2_io_service_rearm 357 382 +25 > intel_pmu_hw_config 1277 1285 +8 > get_sigframe.isra.constprop 1657 1665 +8 > csum_partial_copy_from_user 605 603 -2 > wait_consider_task 3807 3797 -10 > __acct_update_integrals 384 373 -11 > pipe_to_sendpage 459 447 -12 > Total: Before=312759461, After=312759467, chg +0.00% > > It definitely influence the way the compiler optimizes the code. Small addition: Results with allyesconfig and KCOV, KASAN, KUBSAN, FTRACE, TRACE_BRANCH_PROFILING, PROFILE_ALL_BRANCHES disabled: ./scripts/bloat-o-meter ./vmlinux-000 ./vmlinux add/remove: 0/0 grow/shrink: 2/3 up/down: 22/-22 (0) Function old new delta i40e_xmit_xdp_ring 457 477 +20 __acct_update_integrals 127 129 +2 csum_partial_copy_from_user 208 207 -1 dpaa2_io_service_rearm 180 177 -3 wait_consider_task 1338 1320 -18 For defconfig: ./scripts/bloat-o-meter ./vmlinux-000 ./vmlinux add/remove: 0/0 grow/shrink: 3/1 up/down: 16/-5 (11) Function old new delta do_signal 1513 1521 +8 wait_consider_task 2151 2157 +6 __acct_update_integrals 127 129 +2 csum_partial_copy_from_user 223 218 -5 Denis