From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mailhub1.si.c-s.fr (2.236.17.93.rev.sfr.net [93.17.236.2]) by lists.ozlabs.org (Postfix) with ESMTP id 83FDC1A0372 for ; Mon, 17 Aug 2015 20:56:51 +1000 (AEST) Message-ID: <55D1BDF0.4090008@c-s.fr> Date: Mon, 17 Aug 2015 12:56:48 +0200 From: leroy christophe MIME-Version: 1.0 To: Segher Boessenkool , Scott Wood CC: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/2] powerpc32: optimise csum_partial() loop References: <67cf476f657e87b2ea586951a57ae3ba3c1e3c0c.1435655733.git.christophe.leroy@c-s.fr> <20150806003059.GD18479@gate.crashing.org> <1438828301.2097.126.camel@freescale.com> <20150806043938.GE18479@gate.crashing.org> <1438901145.2097.170.camel@freescale.com> <20150806232506.GB22196@gate.crashing.org> In-Reply-To: <20150806232506.GB22196@gate.crashing.org> Content-Type: text/plain; charset=windows-1252; format=flowed List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Le 07/08/2015 01:25, Segher Boessenkool a écrit : > On Thu, Aug 06, 2015 at 05:45:45PM -0500, Scott Wood wrote: >> If this makes performance non-negligibly worse on other 32-bit chips, and is >> an important improvement on 8xx, then we can use an ifdef since 8xx already >> requires its own kernel build. I'd prefer to see a benchmark showing that it >> actually does make things worse on those chips, though. > And I'd like to see a benchmark that shows it *does not* hurt performance > on most chips, and does improve things on 8xx, and by how much. But it > isn't *me* who has to show that, it is not my patch. Ok, following this discussion I made some additional measurement and it looks like: * There is almost no change on the 885 * There is a non negligeable degradation on the 8323 (19.5 tb ticks instead of 15.3) Thanks for pointing this out, I think my patch is therefore not good. Christophe