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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 42D32C433ED for ; Tue, 11 May 2021 13:53:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F146F61004 for ; Tue, 11 May 2021 13:53:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231639AbhEKNyl (ORCPT ); Tue, 11 May 2021 09:54:41 -0400 Received: from mail-40136.protonmail.ch ([185.70.40.136]:25711 "EHLO mail-40136.protonmail.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231634AbhEKNyi (ORCPT ); Tue, 11 May 2021 09:54:38 -0400 Date: Tue, 11 May 2021 13:53:22 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=pm.me; s=protonmail; t=1620741209; bh=jI9W9Blj/Z2qjs3mmYq2tUWMQe2pKTQ81XNwCTvedF4=; h=Date:To:From:Cc:Reply-To:Subject:In-Reply-To:References:From; b=bmoJ+2g9V7Dr5u4+mbx7+VWWI+VbNHXRu4+Pl5zJLxdO8By602YaZnUhpNrhCPfuf sbGhHBahrMkDSDYReFAPMkFqjPE4x8cpaOrhYQFoA7Pi1+JJpqo2n3DHog4Fh835IC SwuVMUMGEUTEyCy9h6K2k7Z4cDonsp1kjOs5B/RUpmFc3r7Ss/JE9LUqblCbvvDEXx X5UcOUlKsJbrg/1ok2jCKdAkre6tcBWjrhWXBXIkhyoJ08J+Lla6ZGEPrALMFwxfe2 LE2Q2pde3JcBQWvSUEPsRbmeMTCpqwnoDjzV6LAHmwvfrzXiUkzv2GjOwBGQhfzl1p apSpWWjgxYVgA== To: Yury Norov From: Alexander Lobakin Cc: Alexander Lobakin , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, Alexey Klimov , Andy Shevchenko , Anton Ivanov , Arnd Bergmann , Borislav Petkov , Catalin Marinas , Christian Borntraeger , Dan Williams , "H. Peter Anvin" , Heiko Carstens , Ingo Molnar , Jacob Keller , Jarkko Sakkinen , Jeff Dike , Kees Cook , Mark Brown , Matti Vaittinen , Nick Terrell , Palmer Dabbelt , Rasmus Villemoes , Richard Weinberger , Thomas Bogendoerfer , Thomas Gleixner , Vasily Gorbik , Vijayanand Jitta , Vineet Gupta , Will Deacon , Yogesh Lal Reply-To: Alexander Lobakin Subject: Re: [PATCH] all: remove GENERIC_FIND_FIRST_BIT Message-ID: <20210511134551.18721-1-alobakin@pm.me> In-Reply-To: <20210510233421.18684-1-yury.norov@gmail.com> References: <20210510233421.18684-1-yury.norov@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org From: Yury Norov Date: Mon, 10 May 2021 16:34:21 -0700 > In the 5.12 cycle we enabled the GENERIC_FIND_FIRST_BIT config option > for ARM64 and MIPS. It increased performance and shrunk .text size; and > so far I didn't receive any negative feedback on the change. > > https://lore.kernel.org/linux-arch/20210225135700.1381396-1-yury.norov@gm= ail.com/ > > I think it's time to make all architectures use find_{first,last}_bit() > unconditionally and remove the corresponding config option. > > This patch doesn't introduce functional changes for arc, arm64, mips, > s390 and x86 because they already enable GENERIC_FIND_FIRST_BIT. There > will be no changes for arm because it implements find_{first,last}_bit > in arch code. For other architectures I expect improvement both in > performance and .text size. > > It would be great if people with an access to real hardware would share > the output of bloat-o-meter and lib/find_bit_benchmark. > > Signed-off-by: Yury Norov > --- > arch/arc/Kconfig | 1 - > arch/arm64/Kconfig | 1 - > arch/mips/Kconfig | 1 - MIPS bit: Reviewed-by: Alexander Lobakin Tested-by: Alexander Lobakin > arch/s390/Kconfig | 1 - > arch/x86/Kconfig | 1 - > arch/x86/um/Kconfig | 1 - > include/asm-generic/bitops/find.h | 12 ------------ > lib/Kconfig | 3 --- > 8 files changed, 21 deletions(-) Thanks, Al