From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Sun, 14 Oct 2007 20:33:56 +0100 (BST) Received: from nf-out-0910.google.com ([64.233.182.186]:7116 "EHLO nf-out-0910.google.com") by ftp.linux-mips.org with ESMTP id S20035422AbXJNTds (ORCPT ); Sun, 14 Oct 2007 20:33:48 +0100 Received: by nf-out-0910.google.com with SMTP id c10so1094106nfd for ; Sun, 14 Oct 2007 12:33:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:user-agent:mime-version:to:cc:subject:references:in-reply-to:content-type:content-transfer-encoding; bh=p9NhzuDoyLH5o//qt7Whgd5IsZ3CX41f/F8RBN+O5UM=; b=eKo8qu1XUzD11Xjj3h5QtHu7jHDGhcWdNYs7DzrQwGERWIcpifW9z4XTn5EHr8B4Kc6MaakATUAHJi7bFKF8diBbny3S++mkd5eeVT7Tg/9HKhbTg8iDc9ZWHuWdtemnrQ2w6MWxqNiH7xmXXqOL6vbtu2Nd9nP3o0B6EXLxkzs= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:user-agent:mime-version:to:cc:subject:references:in-reply-to:content-type:content-transfer-encoding; b=Xrhm1aSBIse3skb7Oe1e3wMB4dH5f4NT4Gscc2Ywc5iiw0OK5twn59X+65QsYxU/59QkktwW47FVUJ3ky/eb7417uHKhX73GtX6+BcbtWRrzgxsYqHDNAfPEQ9tMN18pMr3jLOoyF1hSABiwn2mKE6JdbbWvBXegJvDcXJUC9mg= Received: by 10.86.77.5 with SMTP id z5mr4355286fga.1192390410400; Sun, 14 Oct 2007 12:33:30 -0700 (PDT) Received: from ?192.168.0.1? ( [82.235.205.153]) by mx.google.com with ESMTPS id w7sm5709448mue.2007.10.14.12.33.28 (version=TLSv1/SSLv3 cipher=RC4-MD5); Sun, 14 Oct 2007 12:33:29 -0700 (PDT) Message-ID: <47126EDC.1060305@gmail.com> Date: Sun, 14 Oct 2007 21:32:44 +0200 From: Franck Bui-Huu User-Agent: Thunderbird 2.0.0.5 (X11/20070719) MIME-Version: 1.0 To: "Maciej W. Rozycki" CC: Ralf Baechle , Thiemo Seufer , linux-mips@linux-mips.org Subject: Re: [PATCH] mm/pg-r4k.c: Dump the generated code References: <20071002141125.GC16772@networkno.de> <20071002154918.GA11312@linux-mips.org> <47038874.9050704@gmail.com> <20071003131158.GL16772@networkno.de> <4703F155.4000301@gmail.com> <20071003201800.GP16772@networkno.de> <47049734.6050802@gmail.com> <20071004121557.GA28928@linux-mips.org> <4705004C.5000705@gmail.com> <4705EFE5.7090704@gmail.com> <470A4349.9090301@gmail.com> <470BE1F4.3070800@gmail.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 17021 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: vagabon.xyz@gmail.com Precedence: bulk X-list: linux-mips Maciej W. Rozycki wrote: > On Tue, 9 Oct 2007, Franck Bui-Huu wrote: > >>> What would be the gain for the kernel from using "-march=4ksd" rather >>> than "-march=mips32r2"? >>> >> It actually results in a kernel image ~30kbytes smaller for the former >> case. It has been discussed sometimes ago on this list. I'm sorry but >> I don't know why... > > Perhaps the pipeline description for the 4KSd CPU is different from the > default for the MIPS32r2 ISA. Barring a study of GCC sources, if that > really troubles you, you could build the same version of the kernel with > these options: > > 1. "-march=mips32r2" > > 2. "-march=4ksd" > > 3. "-march=mips32r2 -mtune=4ksd" > > and compare the results. I expect the results of #2 and #3 to be the same > and it would just back up my suggestion about keeping CPU-specific > optimisations separate from the CPU selection. I think you misunderstood me, my own fault: the kernel was smaller with "-march=4ksd". It was bigger when using "-march=mips32r2 -smartmips". I was using SDE gcc. Franck