From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Mon, 15 Oct 2007 20:37:18 +0100 (BST) Received: from nf-out-0910.google.com ([64.233.182.190]:18195 "EHLO nf-out-0910.google.com") by ftp.linux-mips.org with ESMTP id S20037600AbXJOThJ (ORCPT ); Mon, 15 Oct 2007 20:37:09 +0100 Received: by nf-out-0910.google.com with SMTP id c10so1356540nfd for ; Mon, 15 Oct 2007 12:36:52 -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=qOPllCOmPWxHHHe8Zal/cb3NU26XR9+bFfn50dmzFZA=; b=V7ZaJW928h1sxpWmIyZYlTa3ymULdEYsQHF2xOC02MNt8mYO2ypAlpWGaMxZLd++ilbqkwXf+jvSeMBsz6hFVBIYX1OVmepyrNQbYiMGiFHU84eaml50qeXHUxL6dkGvnUEtQrcQWjSKUnqXxB8yp9tMK5THEdUUGiqWQCI+6aM= 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=aSVRR2KGELTQnNz39jDsjzXEzBsrDhvxaXBiBMGll/pwrwMRnoyaYia13WuEgrBBsZ5qsRoseBTc98k7/qeKRR8F9/wcy0OZ5//lmaYt4xNkR74u1GVe5MZIM2tgr5v2Tmf1jwLbV9JXoz6nm/RO4feBLNxSpqxUv8VNTL3bEyg= Received: by 10.86.51.2 with SMTP id y2mr5200995fgy.1192477011771; Mon, 15 Oct 2007 12:36:51 -0700 (PDT) Received: from ?192.168.0.1? ( [82.235.205.153]) by mx.google.com with ESMTPS id b17sm8604048fka.2007.10.15.12.36.50 (version=TLSv1/SSLv3 cipher=RC4-MD5); Mon, 15 Oct 2007 12:36:51 -0700 (PDT) Message-ID: <4713C11F.3010903@gmail.com> Date: Mon, 15 Oct 2007 21:35:59 +0200 From: Franck Bui-Huu User-Agent: Thunderbird 2.0.0.5 (X11/20070719) MIME-Version: 1.0 To: Thiemo Seufer CC: "Maciej W. Rozycki" , Ralf Baechle , linux-mips@linux-mips.org Subject: Re: [PATCH] mm/pg-r4k.c: Dump the generated code References: <20071004121557.GA28928@linux-mips.org> <4705004C.5000705@gmail.com> <4705EFE5.7090704@gmail.com> <470A4349.9090301@gmail.com> <470BE1F4.3070800@gmail.com> <47126EDC.1060305@gmail.com> <20071014195324.GT3379@networkno.de> In-Reply-To: <20071014195324.GT3379@networkno.de> 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: 17055 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 Thiemo Seufer wrote: > Could you check what "-march=mips32r2 -smartmips -mtune=4ksd" does? > I expect it to have the same result than "-march=4ksd". > OK, I give it a try and here are some figures: $ mipsel-linux-size mipssde-6.05.00-20061023/vmlinux~* text data bss dec hex filename 1446130 58456 93056 1597642 1860ca mipssde-6.05.00-20061023/vmlinux~4ksd 1472034 58456 93056 1623546 18c5fa mipssde-6.05.00-20061023/vmlinux~mips32r2-smartmips 1446130 58456 93056 1597642 1860ca mipssde-6.05.00-20061023/vmlinux~mips32r2-smartmips-mtune4ksd So you're right "-march=mips32r2 -smartmips -mtune=4ksd" gives the same result as "-march=4ksd" And the extra space given by "-march=mips32r2 -smartmips" is coming from some additional nop instructions: $ mipsel-linux-objdump -D vmlinux~mips32r2-smartmips > vmlinux~mips32r2-smartmips.S $ mipsel-linux-objdump -D vmlinux~4ksd > vmlinux~4ksd.S $ grep -c nop *.S vmlinux~4ksd.S:18708 vmlinux~mips32r2-smartmips.S:27895 It seems that these extra nops are used for load delays. For example: vmlinux~4ksd.S: -------------- c00008b4: 8fa40040 lw a0,64(sp) c00008b8: 27a40018 addiu a0,sp,24 c00008bc: 0c000148 jal c0000520 vmlinux~mips32r2-smartmips.S: --------------------------- c00008b8: 8fa40040 lw a0,64(sp) c00008bc: 00000000 nop c00008c0: 27a40018 addiu a0,sp,24 c00008c4: 0c000148 jal c0000520 Franck