From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-f194.google.com (mail-pg1-f194.google.com [209.85.215.194]) by dpdk.org (Postfix) with ESMTP id BA26F1B3A1 for ; Wed, 1 Aug 2018 23:03:59 +0200 (CEST) Received: by mail-pg1-f194.google.com with SMTP id n7-v6so4117pgq.4 for ; Wed, 01 Aug 2018 14:03:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=pCXCi2TZaKq0wSLBVQHEWLMX/2hwpVDiZhlJW2xOczg=; b=J82naYrJ6+MnRNHxHWNEa5/K1jB8Dlf/ujxF3gIk72mFDlP0hAJQ/iMdnsMBoFK8L3 kO82lmdZ0PsFyHlNCjq+/Mz6uMWPeyElk1KpDLXljAJcrLtp7q6l6R9Ch1YQFcUs9lcD feYh1cEEsSusTEy5XCEL/QOr91GebF+RiahYl3NkskW1PtueG6WdyXd7Cz/i0r7r+VsS 1MD/f1XehrY9z4sskkrD/lJ5q/vf8enneQ3zpfBYD1jMZg0BRcUKjKzG/xGp+ZejeQub R7EDr/NTT5tuKrvyRvAvhryeSnrhLJe4hTTP6itmR6exzT3EE9VkqZBCbSnhuB9thS7y A0aQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=pCXCi2TZaKq0wSLBVQHEWLMX/2hwpVDiZhlJW2xOczg=; b=kZfroxpv+MJBZlsjpIy4wmrghJXjNB00SQVwAWQbSqurtz22kKQQLBtDV3FiHRW+74 YJ05XPiF+vsvBG2L9Cxm9QboeroE+1ZVil9q6UHQPGvFPwXVpZw+pVee7qLHTmTI7tXB PFEnXecpiUh3ka0r5uDJ7utqZN1eVSDRw0yTBE58zTEl8YPVHeojXZ0kne2MXsbqDM3z khTdFLhTdGoDxAh9/lbuHWMsuvCcG532uZDv4fTB6UDMgaJPDsSLR7uofdz6dJP0Juj7 APUjEXRVFQ8tGW2rNECAhwsXw3Nqs+cYk+A44NUm0YEBJa5maNvrj6UBdMt0wK9h9AXX jtiA== X-Gm-Message-State: AOUpUlFwE/dABZyLo2pa/MhlFzxjP+ZRk9BcUkCweNc8VkLrNQAtbfwM /IfwckME6MtF1iTw+A0oFYccOQ== X-Google-Smtp-Source: AAOMgpf7CH/BP8ORcOxqJfbs10He3+BVEhybARKhUgNZTr1t4CnqpqNUCVc/qh96r7weeKSLG5Y71w== X-Received: by 2002:a63:d946:: with SMTP id e6-v6mr14549pgj.24.1533157438758; Wed, 01 Aug 2018 14:03:58 -0700 (PDT) Received: from xeon-e3 (204-195-22-127.wavecable.com. [204.195.22.127]) by smtp.gmail.com with ESMTPSA id e14-v6sm20699057pff.128.2018.08.01.14.03.58 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 01 Aug 2018 14:03:58 -0700 (PDT) Date: Wed, 1 Aug 2018 14:03:56 -0700 From: Stephen Hemminger To: Yongseok Koh Cc: Adrien Mazarguil , "dev@dpdk.org" Message-ID: <20180801140356.5ac88c43@xeon-e3> In-Reply-To: <50204CDA-B4AD-44C8-AB07-2FE9C2A412C0@mellanox.com> References: <20180731163059.27085-1-stephen@networkplumber.org> <20180731164840.GD5211@6wind.com> <20180731110737.38555f02@xeon-e3> <50204CDA-B4AD-44C8-AB07-2FE9C2A412C0@mellanox.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-dev] [PATCH 0/5] remove usage of register keyword in C X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 01 Aug 2018 21:04:00 -0000 On Wed, 1 Aug 2018 18:03:04 +0000 Yongseok Koh wrote: > > On Jul 31, 2018, at 11:07 AM, Stephen Hemminger wrote: > > > > On Tue, 31 Jul 2018 18:48:40 +0200 > > Adrien Mazarguil wrote: > > > >> On Tue, Jul 31, 2018 at 09:30:54AM -0700, Stephen Hemminger wrote: > >>> Declaring variables as register in C is a leftover from an earlier > >>> era (like cassette tape decks in cars). > >> > >> I don't agree here. It's a hint for compilers and developers that the > >> address of such variables won't be needed (and cannot be taken) to enable > >> whatever optimizations are possible knowing this. > >> > >> Somewhat like inline functions, it's not a forced optimization, just a > >> useful hint that shouldn't hurt if used wisely. > >> > >> Besides, cassette decks are not dead yet :) > > > > If you look at the code, that is not how register is being used (ie. don't take > > address of this). It seems like an attempt at optimization. > > I know compilers are smart enough and the occurrences in mlx4/5 were made from > my old fashioned habit. But, I don't see any urgency to push this patch in RC > stage even though I'm 99% sure that it is harmless. And in general I don't even > understand why we can't live with that if it isn't harmful (or a violation) but > informative. I mean no badness but at least one goodness :-) > > Thanks, > Yongseok > Sure, this is intended for next release not rc stage. Just trying to clean up code base where I see it.