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 AF11C139083 for ; Tue, 5 Dec 2017 04:17:27 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id CEDCBE0DA6; Tue, 5 Dec 2017 04:17:20 +0000 (UTC) Received: from mail-yb0-x241.google.com (mail-yb0-x241.google.com [IPv6:2607:f8b0:4002:c09::241]) (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 6C3E4E090A for ; Tue, 5 Dec 2017 04:17:20 +0000 (UTC) Received: by mail-yb0-x241.google.com with SMTP id j7so2936087ybl.3 for ; Mon, 04 Dec 2017 20:17:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to; bh=NvvTixmmFme1e7UZJvTbNiQGtOrUTusR9bZQbaX80dY=; b=igb7N367y6sbt8ma6pCmUrZ9inDQVkdovpVzISI6nFvr6hcJSwNcAVzeCES468fxBP mS+5DsWNDBCkkI55+B8h0eYt+b099Z8Mvafe1Xq1fu66sii9mUA5MAL/Omzqvnh8oKcQ TDkj4Vm3LrXdr6ccRF4iVrccmgdTm+AbGr5xa2aUFpKFF/hCO5/t4hMc1CAoyJaEM5gI DtZs19nA3ft7E2+1WBmpWgafjjWT4DsGPgQRZTMcKT/1RS+U1x/klxTt5+cjIVlif09A ZPs53s682u6BpctcfVfLUwyqVjY3yRylNxntGY/wf7epR5IbOLBuqSi1CAKrVnPm/Tke k+VA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to; bh=NvvTixmmFme1e7UZJvTbNiQGtOrUTusR9bZQbaX80dY=; b=RtW2yTGeFxV0iUs3OpJCN8r1fcR1Ri7COEu8ZGu45Y6gi3uBmfGlelm788T65TZjuA 7qZ003jdSP++h49dGRYRYdvrnRAKJ64aJbBIy/f8g1lHC/ILurc4Mi0Tvtb8gvXnj6Xv GLcWuJW2R8WTWlvxvk7/W5HEWIEI1omgb6KGN3DiMPPckVxz9kXNU/VVsnP/fFAfVIkq s01uEIoBikAYdaqwhGA8evsD6gcKdb6nh4ITJjjCFlv2m21a80Qfzmd5gIL3MKJTxb0I g5rKOnr0t/lGJV0bvp94jyEB4rNjpvozgRZyCrMq5bLxC2FuEzltcVNeoW6kH5i3RYg6 ZGzw== X-Gm-Message-State: AJaThX6UrCB0ngIcLr48mWZwyMYfHJoZMoW4A6Uc2Up6/P2Lba0oWCcG RM45NN6m4pIRSeDn5ofYercy4WtZ/ZyqIdercc4= X-Google-Smtp-Source: AGs4zMaPLrN+x8Vvf5RYw9yNXl3yjHpQlvgWUjLBVzZno0EE7dX+S10oUfC+QNTdS9qzK0NnWWZY6y3RX36PTnjvdGo= X-Received: by 10.37.92.84 with SMTP id q81mr12065900ybb.180.1512447438924; Mon, 04 Dec 2017 20:17:18 -0800 (PST) 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 Received: by 10.13.234.16 with HTTP; Mon, 4 Dec 2017 20:17:18 -0800 (PST) In-Reply-To: References: <6b5fbeca-453c-f103-5e4e-a8db83a6dabf@st.com> <5A158B10.6090007@youngman.org.uk> <6661527.9k004Oio64@eve> From: R0b0t1 Date: Mon, 4 Dec 2017 22:17:18 -0600 Message-ID: Subject: Re: [gentoo-user] is multi-core really worth it? To: gentoo-user@lists.gentoo.org Content-Type: text/plain; charset="UTF-8" X-Archives-Salt: daa9e43a-2bc4-4729-a714-a27029635786 X-Archives-Hash: 5a5b18af6f6cd6861a4c4e2f58a1a3e6 On Mon, Dec 4, 2017 at 10:11 PM, Taiidan@gmx.com wrote: > On my 16 core opteron I have to do -j32 or sometimes -j64 to be using > everything all the time, is this normal? If I don't do this it won't be > pegged at 100% all the time. > I use a ramdisk and anything over -j${NCPU} (incl. hyperthreaded cores) causes performance degradation in general due mainly to the compiling step. For some package sets I have noticed that higher build parallelism helps due to some ebuild steps not being easily parallelizable. > I assume using a ramdisk would help with this? I wouldn't want to do a SSD > as I assume it would excessively wear by doing compiles. > It should. While builds on an SSD will wear the SSD, comparing the write volume to the expected drive lifetime will tell you the true impact. It is (if I remember) still relatively small. Cheers, R0b0t1