From owner-freebsd-stable@freebsd.org Mon Jan 23 06:57:48 2017 Return-Path: Delivered-To: freebsd-stable@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 0B1F8CBD13F for ; Mon, 23 Jan 2017 06:57:48 +0000 (UTC) (envelope-from walterp@gmail.com) Received: from mail-qt0-x230.google.com (mail-qt0-x230.google.com [IPv6:2607:f8b0:400d:c0d::230]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id B60DCB8A for ; Mon, 23 Jan 2017 06:57:47 +0000 (UTC) (envelope-from walterp@gmail.com) Received: by mail-qt0-x230.google.com with SMTP id k15so108508507qtg.3 for ; Sun, 22 Jan 2017 22:57:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:from:date:message-id:subject:to; bh=g7oQ1JkEgFtLZDo+T8LMr6aKauSkxk62CgnEXrdKPtY=; b=aE7Yod0d3uOjduHlXDxbWk6odO9BUslCHLf9ApLV7VVhbajGhkc9iDDklaGxFucqqR C/0qBuRrgF0pT4DJdBTjDd7Baw2AqityW134yDA/T0gl+KYtWzdYVnzGhel5S1SLZMeS WxQy9lfF/WLd01TGwc0f6Q0XKJpLntB0BeaOWIy3JLKObdq/FPRttoyEaWhZOzjDTF7f DP0BPzscvq78zhRGU2px0btN97q+d21X3jQcHc+m72cIZ69GvXlI21+uj5yNeNPiqwi1 oUL1s12iy2qRCEA9JDtKy0RIveaJdQ9FVMSBlRt7IZN58m5AoLYtMuM25oIHS5/vuyW0 GW2A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to; bh=g7oQ1JkEgFtLZDo+T8LMr6aKauSkxk62CgnEXrdKPtY=; b=Sp9AQCOG56A7qsFPFnsiCuiWfyKTgqVzIl7BIJwEim2Wx+mMwxxVrfuoVK6nWFhRxl +2/cTln0Hx9Nu9u0h9WMohiWXtkHoR8JZtIjR9oMKTVoQl0yHqR87L729yQuiLZDbfTa Orsm68stvo1nMYiEIPbMsJcjxuUskPyq918O+Nmi7vdUkqcyfpXFsWmiNUCzelg0zlaA M38wq3znzcD3Fzzi4xExdz01mPVGio+vwykKHQiqKIa2gGfNKueZ+hhnhruKhLAu6FfG tC6cLjbu64rnPzUGZwLUWZxdpz8xi2+FjNFJeWPLBlmhTDZrclIRI5G/BZAz44oiMrgP +LMA== X-Gm-Message-State: AIkVDXJQR7A1bMPi36XBt3XFHFD2T1czE2vC95bUf0ryB40+q1WtnIw0tbs6CSVc/7b5D7yGx3IRAuvm8mcEmw== X-Received: by 10.55.210.135 with SMTP id f129mr22473061qkj.184.1485154666815; Sun, 22 Jan 2017 22:57:46 -0800 (PST) MIME-Version: 1.0 Received: by 10.12.162.33 with HTTP; Sun, 22 Jan 2017 22:57:46 -0800 (PST) From: Walter Parker Date: Sun, 22 Jan 2017 22:57:46 -0800 Message-ID: Subject: Building Kernel and World with -j To: freebsd-stable@freebsd.org Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.23 X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 23 Jan 2017 06:57:48 -0000 Hi, For decades there has always been a warning not to do parallel builds of the kernel or the world (Linux kernel builds also suggest not to do this). Every once in a while, I see people post about 5 minutes. This only way I can see this happening is by doing a parallel build (-j 16 on a Xeon Monster box). Are parallel builds safe? If not, what are actual risk factors and can they be mitigated? Walter -- The greatest dangers to liberty lurk in insidious encroachment by men of zeal, well-meaning but without understanding. -- Justice Louis D. Brandeis