From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 40sKr26WRPzF1PF for ; Fri, 25 May 2018 05:55:46 +1000 (AEST) Date: Thu, 24 May 2018 14:55:38 -0500 From: Segher Boessenkool To: Christophe Leroy Cc: linux-kernel@vger.kernel.org, Paul Mackerras , netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH v3] powerpc: Implement csum_ipv6_magic in assembly Message-ID: <20180524195538.GE17342@gate.crashing.org> References: <20180522065701.9DE696CCB4@po14934vm.idsi0.si.c-s.fr> <20180523183447.GV17342@gate.crashing.org> <3848a4ad-2c0e-691f-e98f-347cfe3484e8@c-s.fr> <1dac2356-5d8a-2892-109e-6e1b26c2bd8c@c-s.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 In-Reply-To: <1dac2356-5d8a-2892-109e-6e1b26c2bd8c@c-s.fr> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, May 24, 2018 at 10:18:44AM +0000, Christophe Leroy wrote: > On 05/24/2018 06:20 AM, Christophe LEROY wrote: > >Le 23/05/2018 à 20:34, Segher Boessenkool a écrit : > >>On Tue, May 22, 2018 at 08:57:01AM +0200, Christophe Leroy wrote: > >>>The generic csum_ipv6_magic() generates a pretty bad result > >> > >> > >> > >>Please try with a more recent compiler, what you used is pretty ancient. > >>It's not like recent compilers do great on this either, but it's not > >>*that* bad anymore ;-) > > Here is what I get with GCC 8.1 > It doesn't look much better, does it ? There are no more mfocrf, which is a big speedup. Other than that it is pretty lousy still, I totally agree. This improvement happened quite a while ago, it's fixed in GCC 6. Segher