From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: bit fields && data tearing Date: Wed, 10 Sep 2014 13:18:06 -0700 Message-ID: <5410B1FE.9090504@zytor.com> References: <20140712181328.GA8738@redhat.com> <54079B70.4050200@hurleysoftware.com> <1409785893.30640.118.camel@pasglop> <063D6719AE5E284EB5DD2968C1650D6D17487172@AcuExch.aculab.com> <1409824374.4246.62.camel@pasglop> <5408E458.3@zytor.com> <54090AF4.7060406@hurleysoftware.com> <54091B30.7080100@zytor.com> <5409D76D.2070203@hurleysoftware.com> <5409D9C0.7030403@zytor.com> <20140908185240.21f52ca0@alan.etchedpixels.co.uk> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20140908185240.21f52ca0@alan.etchedpixels.co.uk> Sender: linux-arch-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: One Thousand Gnomes Cc: Peter Hurley , Benjamin Herrenschmidt , David Laight , Jakub Jelinek , "linux-arch@vger.kernel.org" , Tony Luck , "linux-ia64@vger.kernel.org" , Oleg Nesterov , "linux-kernel@vger.kernel.org" , Paul Mackerras , "Paul E. McKenney" , "linuxppc-dev@lists.ozlabs.org" , Miroslav Franc , Richard Henderson , linux-alpha@vger.kernel.org On 09/08/2014 10:52 AM, One Thousand Gnomes wrote: > > I think the whole "removing Alpha EV5" support is basically bonkers. Just > use set_bit in the tty layer. Alpha will continue to work as well as it > always has done and you won't design out support for any future processor > that turns out not to do byte aligned stores. > I think it's pretty safe to say such a processor is unlikely to ever be created, for the same reason there weren't any 48-bit computers when 32-bit computers ran out of steam: it caused more problems than it solved, and Alpha pretty much proved that. The engineering advantages would have to be so overwhelmingly in favor for someone to want to walk down that road again. -hpa From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Date: Wed, 10 Sep 2014 20:18:06 +0000 Subject: Re: bit fields && data tearing Message-Id: <5410B1FE.9090504@zytor.com> List-Id: References: <20140712181328.GA8738@redhat.com> <54079B70.4050200@hurleysoftware.com> <1409785893.30640.118.camel@pasglop> <063D6719AE5E284EB5DD2968C1650D6D17487172@AcuExch.aculab.com> <1409824374.4246.62.camel@pasglop> <5408E458.3@zytor.com> <54090AF4.7060406@hurleysoftware.com> <54091B30.7080100@zytor.com> <5409D76D.2070203@hurleysoftware.com> <5409D9C0.7030403@zytor.com> <20140908185240.21f52ca0@alan.etchedpixels.co.uk> In-Reply-To: <20140908185240.21f52ca0@alan.etchedpixels.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: One Thousand Gnomes Cc: Peter Hurley , Benjamin Herrenschmidt , David Laight , Jakub Jelinek , "linux-arch@vger.kernel.org" , Tony Luck , "linux-ia64@vger.kernel.org" , Oleg Nesterov , "linux-kernel@vger.kernel.org" , Paul Mackerras , "Paul E. McKenney" , "linuxppc-dev@lists.ozlabs.org" , Miroslav Franc , Richard Henderson , linux-alpha@vger.kernel.org On 09/08/2014 10:52 AM, One Thousand Gnomes wrote: > > I think the whole "removing Alpha EV5" support is basically bonkers. Just > use set_bit in the tty layer. Alpha will continue to work as well as it > always has done and you won't design out support for any future processor > that turns out not to do byte aligned stores. > I think it's pretty safe to say such a processor is unlikely to ever be created, for the same reason there weren't any 48-bit computers when 32-bit computers ran out of steam: it caused more problems than it solved, and Alpha pretty much proved that. The engineering advantages would have to be so overwhelmingly in favor for someone to want to walk down that road again. -hpa From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.zytor.com (terminus.zytor.com [IPv6:2001:1868:205::10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id C834A1A006C for ; Thu, 11 Sep 2014 06:18:31 +1000 (EST) Message-ID: <5410B1FE.9090504@zytor.com> Date: Wed, 10 Sep 2014 13:18:06 -0700 From: "H. Peter Anvin" MIME-Version: 1.0 To: One Thousand Gnomes Subject: Re: bit fields && data tearing References: <20140712181328.GA8738@redhat.com> <54079B70.4050200@hurleysoftware.com> <1409785893.30640.118.camel@pasglop> <063D6719AE5E284EB5DD2968C1650D6D17487172@AcuExch.aculab.com> <1409824374.4246.62.camel@pasglop> <5408E458.3@zytor.com> <54090AF4.7060406@hurleysoftware.com> <54091B30.7080100@zytor.com> <5409D76D.2070203@hurleysoftware.com> <5409D9C0.7030403@zytor.com> <20140908185240.21f52ca0@alan.etchedpixels.co.uk> In-Reply-To: <20140908185240.21f52ca0@alan.etchedpixels.co.uk> Content-Type: text/plain; charset=ISO-8859-1 Cc: Jakub Jelinek , "linux-arch@vger.kernel.org" , Tony Luck , "linux-ia64@vger.kernel.org" , Peter Hurley , Oleg Nesterov , "linux-kernel@vger.kernel.org" , David Laight , Paul Mackerras , linux-alpha@vger.kernel.org, "Paul E. McKenney" , "linuxppc-dev@lists.ozlabs.org" , Miroslav Franc , Richard Henderson List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 09/08/2014 10:52 AM, One Thousand Gnomes wrote: > > I think the whole "removing Alpha EV5" support is basically bonkers. Just > use set_bit in the tty layer. Alpha will continue to work as well as it > always has done and you won't design out support for any future processor > that turns out not to do byte aligned stores. > I think it's pretty safe to say such a processor is unlikely to ever be created, for the same reason there weren't any 48-bit computers when 32-bit computers ran out of steam: it caused more problems than it solved, and Alpha pretty much proved that. The engineering advantages would have to be so overwhelmingly in favor for someone to want to walk down that road again. -hpa