From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pigeon.gentoo.org ([69.77.167.62] helo=lists.gentoo.org) by finch.gentoo.org with esmtp (Exim 4.60) (envelope-from ) id 1LUUQg-0002r8-Ty for garchives@archives.gentoo.org; Tue, 03 Feb 2009 23:11:43 +0000 Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 90640E04C2; Tue, 3 Feb 2009 23:10:32 +0000 (UTC) Received: from ey-out-1920.google.com (ey-out-1920.google.com [74.125.78.147]) by pigeon.gentoo.org (Postfix) with ESMTP id 53507E04C2 for ; Tue, 3 Feb 2009 23:10:32 +0000 (UTC) Received: by ey-out-1920.google.com with SMTP id 13so256996eye.10 for ; Tue, 03 Feb 2009 15:10:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=gamma; h=domainkey-signature:received:received:from:to:subject:date :user-agent:references:in-reply-to:mime-version:content-type :content-transfer-encoding:content-disposition:message-id; bh=EyHgMYjBpfXb64xd88+APXAFFArgB7659geEZuAJ3bI=; b=FRH23cL+MEL9/1vGLT5/Dh+Vql7okRoXpyTt83Ptw8FICMSttAn5P5IGUJZa6tnp5P nu1aHTK5S4Z5Jt2kP02FSQWiPpTXEKBcP7xu8AjTA2t38wLzaKdBXsowuLGOvgGRzf5J BNA8c4f7SdyGAmbaqmppKXAhXaZz1NuV2d1wU= DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=from:to:subject:date:user-agent:references:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :message-id; b=tH6cRhdT2y83mcJhCEIpm7cBWCiGA/rynJfpNn61SfJnAJ/BBW3u0vkyBJF0d7P69b hXKweiwTu0GSANKach/asgcTwLIv2GvYG0XYDpP1p6IgpoEMAHLyZII9n/qoSpgRbbq/ DGkpTSpeuQEnHSAHzVrRDZ8rmUcfFzIrdRTEE= Received: by 10.210.51.18 with SMTP id y18mr387438eby.103.1233702631771; Tue, 03 Feb 2009 15:10:31 -0800 (PST) Received: from energy.localnet (energy.heim10.tu-clausthal.de [139.174.197.94]) by mx.google.com with ESMTPS id 2sm12696770ewy.72.2009.02.03.15.10.31 (version=TLSv1/SSLv3 cipher=RC4-MD5); Tue, 03 Feb 2009 15:10:31 -0800 (PST) From: Volker Armin Hemmann To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] Gentoo's advantage: "optimized for your system" -- huh? Date: Wed, 4 Feb 2009 00:10:25 +0100 User-Agent: KMail/1.11.0 (Linux/2.6.27.13r4; KDE/4.2.0; x86_64; ; ) References: In-Reply-To: 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 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200902040010.26237.volkerarmin@googlemail.com> X-Archives-Salt: 2def9aa8-d9d2-4203-84f0-9ec93d17be5b X-Archives-Hash: a49804cd24c8cb482a4f34c9d47668da On Dienstag 03 Februar 2009, Grant Edwards wrote: > Whenever I see a write-up of Gentoo, it's describe as a system > similar to BSD "ports" where you build packages from source. > The main benefit claimed for this approach is that you get > better performance because all executables are optimized for > exactly the right instruction set. > > Where did that bit of apocrypha come from, and why is it > parroted by so many people? because it was true in the beginning, when most distris were still built for 386 and the difference of an optimized built was that you could watch dvd movies without hangs and frame loss. It is still true to a certain degree today - code compiled for 386 runs much slower than code compiled for core2 - on a core2. But on todays overpowered cpus you don't see it as prominent as back on k6-2 400 or p3 650 .... > AFAICT, the "performance" benefit due to compiler optimization > is practically nil in real-world usage. nope, they are there. But compiler optimiziations are a very delicate thing. You can't just throw funroll-all-loops into make.conf and think that was it. And for a general set, march is the most important one. It does do a lot of good - the rest is just minor at best.