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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 669A4C41604 for ; Tue, 6 Oct 2020 16:11:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1E84B206D4 for ; Tue, 6 Oct 2020 16:11:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725902AbgJFQLK (ORCPT ); Tue, 6 Oct 2020 12:11:10 -0400 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:42868 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725769AbgJFQLJ (ORCPT ); Tue, 6 Oct 2020 12:11:09 -0400 Received: (from willy@localhost) by pcw.home.local (8.15.2/8.15.2/Submit) id 096GAdjf005889; Tue, 6 Oct 2020 18:10:39 +0200 Date: Tue, 6 Oct 2020 18:10:39 +0200 From: Willy Tarreau To: "Paul E. McKenney" Cc: David Laight , "'Nick Clifton'" , Peter Zijlstra , "stern@rowland.harvard.edu" , "linux-toolchains@vger.kernel.org" , Will Deacon , "linux-kernel@vger.kernel.org" , "parri.andrea@gmail.com" , "boqun.feng@gmail.com" , "npiggin@gmail.com" , "dhowells@redhat.com" , "j.alglave@ucl.ac.uk" , "luc.maranget@inria.fr" , "akiyks@gmail.com" , "dlustig@nvidia.com" , "joel@joelfernandes.org" , "torvalds@linux-foundation.org" Subject: Re: Control Dependencies vs C Compilers Message-ID: <20201006161039.GF5822@1wt.eu> References: <20201006114710.GQ2628@hirez.programming.kicks-ass.net> <3dfe7daed3c44f46a6989b6513ad7bb0@AcuMS.aculab.com> <20201006133115.GT2628@hirez.programming.kicks-ass.net> <20201006142324.GB416765@rowland.harvard.edu> <20201006144302.GY2628@hirez.programming.kicks-ass.net> <47bfda8f-304e-5283-c6d6-0753037b0b2c@redhat.com> <1dabfd1939f348198678121f94d6c9b2@AcuMS.aculab.com> <20201006155052.GJ29330@paulmck-ThinkPad-P72> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201006155052.GJ29330@paulmck-ThinkPad-P72> User-Agent: Mutt/1.6.1 (2016-04-27) Precedence: bulk List-ID: X-Mailing-List: linux-toolchains@vger.kernel.org On Tue, Oct 06, 2020 at 08:50:52AM -0700, Paul E. McKenney wrote: > Comparing 25+ assembly languages to but two compilers most definitely > motivates looking hard at doing something with the compilers. +1, especially since the kernel is not special; anyone working with threads faces the same issues in userland, which are often hidden behind the implicit whole-memory clobbers of certain operations or the call to mutex manipulation functions, but which become a reality again as soon as you go slightly away from these and try to use lockless mechanisms. Willy