From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) by finch.gentoo.org (Postfix) with ESMTP id D0201138C9D for ; Thu, 30 Apr 2015 18:12:03 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 61BD4E0858; Thu, 30 Apr 2015 18:11:56 +0000 (UTC) Received: from mail-wi0-f176.google.com (mail-wi0-f176.google.com [209.85.212.176]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 31CB7E0851 for ; Thu, 30 Apr 2015 18:11:55 +0000 (UTC) Received: by widdi4 with SMTP id di4so29607651wid.0 for ; Thu, 30 Apr 2015 11:11:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:subject:references :in-reply-to:content-type:content-transfer-encoding; bh=YAPJSNfTpxxKhsNq8NDdD9dq5vlKMM+QcTdh738eiIo=; b=jU7OmgcGuBCgws3o7r9c6qvgTfGPMNA9lgjhRwnECtXDnYhUhX8N1HGGLBPDRV7qq7 dc2xvffdSu47RUk1sKyeHxy3mtWzVmlCrDgZkvLiNi1OWgLj3aGDEd7rBOoRhc68VlHR UYIFw1SpwPdK7EBVOdSQPGtB+FiEHpReMgpZ0QXIUpK+aUQWa78FwaUiLlg3w44fbCVY 9jsEuNUypl7NFutQsmmPqavBEmEr1aQjAXBs6bh+ycfZ+CnOMqRU0qwkBwSlrPj4brp4 A0eLMEezs76i133fw8GQC1NAvoteotZmFJO3d77AIqobvQWFK6BCopftJhyzaTE9WJwD r/dQ== X-Received: by 10.194.81.104 with SMTP id z8mr10720294wjx.45.1430417514010; Thu, 30 Apr 2015 11:11:54 -0700 (PDT) Received: from [192.168.178.21] (p5B0C5F3F.dip0.t-ipconnect.de. [91.12.95.63]) by mx.google.com with ESMTPSA id 16sm4311964wjs.41.2015.04.30.11.11.52 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 30 Apr 2015 11:11:53 -0700 (PDT) Message-ID: <55427068.5030909@googlemail.com> Date: Thu, 30 Apr 2015 20:11:52 +0200 From: Volker Armin Hemmann User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] CFLAGs for kernel compilation References: <5540C101.70906@ramses-pyramidenbau.de> <554257AE.8020503@googlemail.com> <20150430204518.b89e4a39cab48a9cdf339259@gentoo.org> In-Reply-To: <20150430204518.b89e4a39cab48a9cdf339259@gentoo.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Archives-Salt: 373cce67-348b-4f2b-be69-c8717fbfcf26 X-Archives-Hash: c1436c6cfba066d388b62995e300f0bc Am 30.04.2015 um 19:45 schrieb Andrew Savchenko: > Hi, > > On Thu, 30 Apr 2015 18:26:22 +0200 Volker Armin Hemmann wrote: >> That simple. The kernel is too important and the people programming it >> know what they are doing. Don't set anything. It is retarded. >>> - I don't like invoking 'CFLAGS="-O2 -march=foo"make' >>> - I don't want to set CFLAGS as a persistent environment variable. >>> - I don't want to modify the kernel Makefile >>> >>> Does it actually make sense to set an optimization level and -march? >> no > While I completely agree with you that kernel CFLAGS should not be > randomly tampered with, I can't agree that -march itself is useless. > Tests and results are available here: > https://github.com/graysky2/kernel_gcc_patch > > Optimization is a very powerful tool if taken with care. Of course > it may lead to a disastrous result if mindlessly used. > > Best regards, > Andrew Savchenko if your mail client or browser is miscompiled, it is crashy, but worst case, a bunch of emails or bookmarks are lost. If the kernel fucks up, it might write across partition boundaries and destroy ALL your data. Or writes garbage instead of data. Don't f* with the kernel.