From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by finch.gentoo.org (Postfix) with ESMTPS id 8F4EE139083 for ; Wed, 22 Nov 2017 13:23:13 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 7F30CE0E95; Wed, 22 Nov 2017 13:23:08 +0000 (UTC) Received: from gw2.antarean.org (gw2.antarean.org [141.105.125.208]) by pigeon.gentoo.org (Postfix) with ESMTP id 21425E0D26 for ; Wed, 22 Nov 2017 13:23:07 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by gw2.antarean.org (Postfix) with ESMTP id 23078121A3F for ; Wed, 22 Nov 2017 14:16:58 +0100 (CET) X-Virus-Scanned: amavisd-new at antarean.org Received: from gw2.antarean.org ([127.0.0.1]) by localhost (gw2.antarean.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id m8f2XxZdyjRi for ; Wed, 22 Nov 2017 14:16:57 +0100 (CET) Received: from mailstore1.antarean.org (localhost [127.0.0.1]) by gw2.antarean.org (Postfix) with ESMTP id B653E121A34 for ; Wed, 22 Nov 2017 14:16:57 +0100 (CET) Received: from eve.localnet (eve.adm.antarean.org [10.55.16.44]) by mailstore1.antarean.org (Postfix) with ESMTP id 742BA32 for ; Wed, 22 Nov 2017 14:23:06 +0100 (CET) From: "J. Roeleveld" To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] is multi-core really worth it? Date: Wed, 22 Nov 2017 14:23:06 +0100 Message-ID: <5126763.L5XyAvMajf@eve> Organization: Antarean In-Reply-To: <85555669-e101-e17e-9486-090afbb52784@st.com> References: <6b5fbeca-453c-f103-5e4e-a8db83a6dabf@st.com> <20171122072601.GA18724@gentoo-tp> <85555669-e101-e17e-9486-090afbb52784@st.com> 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-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Archives-Salt: 74e97061-9432-4fab-9c6a-51d85a2b0da6 X-Archives-Hash: 6f7f6170a78565775b8cbefef22422d6 On Wednesday, November 22, 2017 2:12:31 PM CET Raffaele Belardi wrote: > Jeremi Piotrowski wrote: > > That being said: if you do a world rebuild you will have lots of packages > > that spend ~40 seconds doing their autoconf run, only to build 2-3 sources > > files. On an 8-core machine at work, I get good results using parallel > > emerge jobs (emerge -jX). For your 6-core AMD CPU (assuming it actually > > has 12 threads) I'd start with 'emerge -j3' and MAKEOPTS='-j12 -l16'. > > That should get you a nice speedup, but may require a bit more ram. > > emerge -j3 is something I did not think of, I'll try it. But won't that > break portage's carefully crafted package dependencies? I suppose you could > get occasional build failures? No, it won't. If it has multiple packages that can be built (taking dependencies into account) it will. If all packages in the queue are waiting for a single package to be installed, all those will wait till that package is finished. > I'm using MAKEOPTS=-j7, I thought 2 threads per CPU (hyperthreading?) was an > Intel thing only. I thought so too. Don't forget to add the "load-average" option to both, otherwise there is a very likely chance you will have 3 * 7 = 21 build processes running at the same time. Also, I have had situations where using "-j" actually caused some issues where it was picked up by the wrong process or it has a different meaning for some other process. Specifying the long version (--jobs) has been reliable for me. -- Joost