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 388AA1381F3 for ; Tue, 11 Dec 2012 17:38:14 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 5DF15E030B; Tue, 11 Dec 2012 17:38:00 +0000 (UTC) Received: from mailout-de.gmx.net (mailout-de.gmx.net [213.165.64.23]) by pigeon.gentoo.org (Postfix) with SMTP id 6F53B21C05E for ; Tue, 11 Dec 2012 17:36:49 +0000 (UTC) Received: (qmail invoked by alias); 11 Dec 2012 17:36:48 -0000 Received: from wl-l3-183.rz.tu-ilmenau.de (EHLO localhost) [141.24.17.183] by mail.gmx.net (mp041) with SMTP; 11 Dec 2012 18:36:48 +0100 X-Authenticated: #4040096 X-Provags-ID: V01U2FsdGVkX18drLt+zwQdhELGsd1OoOYLQhlXF2rujCD5XJ++br WPrtwOBl3zAPzi Date: Tue, 11 Dec 2012 18:36:47 +0100 From: Frank Steinmetzger To: gentoo-user@lists.gentoo.org Subject: [gentoo-user] Intel Atom: architecture, distcc, crossdev and compile flags Message-ID: <20121211173647.GA32351@eisen.lan> Mail-Followup-To: gentoo-user@lists.gentoo.org 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: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="KsGdsel6WgEHnImy" Content-Disposition: inline User-Agent: Mutt 1.5.21 (2010-09-15, Gentoo 1.5.21-r11) X-Y-GMX-Trusted: 0 X-Archives-Salt: 31ee3e91-3ef9-4ef5-b518-ef858a145afe X-Archives-Hash: b5bb323e5c16370512baa748b94bd0c1 --KsGdsel6WgEHnImy Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hello list Long time no read... :) It follows a verbose preamble. For the actual questions see dashed line be= low. TL;DR summary: it=E2=80=99s all about ricer-performance questions on a netb= ook. I have the luck of having obtained a used netbook for free (Atom N450, sing= le- core with HT, 1 GB memory, 5400 rev HDD). During the last week I=E2=80=99v= e been experimenting with 32 and 64 bits on it and am still quite undecided which = to keep. My reasons: - They are not as far apart in CPU performance as is the Core2. I posted a 32/64 comparison for Core2 a few months ago, which showed that Lilypond speedup on 64 bit was 50%. On the Atom, it actually took 5% long= er. (Sadly, Blender doesn=E2=80=99t build on 32 bit right now). - Startup times for hogs like Firefox and KDE are quite equal between the t= wo (that could be attributed in parts to the fact that the 64 bit partition sits on the disk=E2=80=99s first sectors, while 32 bit sits at the other = end, I don=E2=80=99t know which end is faster). - pro 64: it is very easy to use distcc, as opposed to 32 bits (see below). - con 64: it uses about 50% more memory, 32 bit builds are a little faster. The RAM argument is the most convincing one right now, since more free RAM means more cache, which means a faster system in the long run. Currently, K= DE after logon needs 150 MB on 32 bit, and 250 MB on 64 bit (without akonadi f= or now). But awesome WM rocks on a netbook anyway. ----------[ Questions begin ]----------------------------------------------= -- So I=E2=80=99m interested in you opinion and own experience about the follo= wing arising questions: * From my observations, the benefit of 64 bit over 32 is much smaller for an Atom than it is for my Core2. Am I right to assume thus that the Atom architecture doesn=E2=80=99t have much to offer to 64 bit (such as extra = registers)? I=E2=80=99m not talking about memory here, since it=E2=80=99s limited to = 2 GB in any case. * The problem of distcc between different architectures: The netbook already had an older 32 bit Gentoo installed. And since I ha= ve a multilib host (march=3Dcore2), I though I could upgrade with distcc (us= ing march=3Datom on the netbook). But at some point more and more stuff stop= ped working, eventually I got =E2=80=9Cinvalid instruction=E2=80=9D errors du= ring emerge, hence I figured that was a dead end. So is it possible to mix architectures in this way at all with distcc? I also have crossdev for i686 installed, which even shares files with the system=E2=80=99s normal multilib gcc. I find that odd. I sped up the installation process for 32 bit by using a chroot on the big machine, which worked nicely. But it=E2=80=99s not a long-term solution,= b/c it uses up too much disk space on the host. * I=E2=80=99m interested in the question of -O2 vs. -Os. Some sources say -Os is bad, b/c it breaks debugging and is mainly untest= ed. I won=E2=80=99t do heavy developing on it anyway, and Atoms do have a pun= y cache. So I wonder whether -Os would improve execution time and RAM usage noticably. Diskspace itself is not an issue. * I=E2=80=99m also interested in comparing bin packages over self-compiled = ones. E.g. I did compile icedtea, even if it=E2=80=99s just for TV browser. :) Can you name a Java benchmark to measure CPU performance? * The last thing I=E2=80=99m going to set up is filesystem encryption, at l= east for ~. I already know/think that AES would be the best choice due to limited CPU power, but what else is there to heed besides key size? * What other small benchmarks for CPU and memory can you recommend? So far= I tested with nbench and sysbench. The results are so-and-so. Some computat= ion stuff is much slower on 64 bit, some a bit faster. The applicability to every-day use is of course a wibbly-wobbly argument. I also tested the runtime of some application (packing and unpacking of archives, throughput with dd, mencoder). If there is interest, I can post the result of 21 runs on each platform, measured with GNU time. ----------[ Questions end ]------------------------------------------------= -- PS.: I=E2=80=99m aware that benchmarks are always a bit subjective and non= e is perfect. I also realise that most of the questions quite belong into the ricer corner. But Netbooks are ricer devices, b/c they need to perform at their limits all the time. :-D If you read until this point, thank you very much for your time. You get a unicorn as a reward: `^nn~ --=20 Gru=C3=9F | Greetings | Qapla=E2=80=99 Please do not share anything from, with or about me with any Facebook servi= ce. =E2=80=9CTime is money=E2=80=9D said the waiter and put the date on the bil= l. --KsGdsel6WgEHnImy Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) iEYEARECAAYFAlDHby4ACgkQGafpl66MV0xsGwCeL/qSg2JB9lfuaZeQey455kuW 6JYAn2B24l/m/6E57lcQDclXYH8b+wtr =KvTU -----END PGP SIGNATURE----- --KsGdsel6WgEHnImy--