From owner-freebsd-stable@freebsd.org Thu Jan 26 16:36:25 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 2DC45CC31E8 for ; Thu, 26 Jan 2017 16:36:25 +0000 (UTC) (envelope-from kraduk@gmail.com) Received: from mail-vk0-x22a.google.com (mail-vk0-x22a.google.com [IPv6:2607:f8b0:400c:c05::22a]) (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 D3975F4A for ; Thu, 26 Jan 2017 16:36:24 +0000 (UTC) (envelope-from kraduk@gmail.com) Received: by mail-vk0-x22a.google.com with SMTP id x75so158077433vke.2 for ; Thu, 26 Jan 2017 08:36:24 -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 :cc; bh=1P5MK419CiPsslmLTmG5fBWqfS0HB9ZOwXuACeSc74Y=; b=LIRau2/WaNbbXPfKUrJT6/FowbdiWSnUS+05g3XRfyYO088d5tu+VQALMQtbN7I2O0 ChAKroVLpbuTNHUcnz8bsi3wq4kmmTYATMgFaYCjMAflPeT64Z7U2Qkpr4MPh/ECvwU0 29gwQJjxPi5Xw4lw+cxN19e0QM/hjaNxwdtzP3hKdOsSRi5m4kw+xcdwDSq8Qa1uuAIU Z9oqxbQ+xV+V1jGVD4/DrkqF85JHyTrEr0zAFJk6LLM/0c8oStbx6UfMUh/d2QXbAd0Z +MCbKwA7GAzFUeBYp2aTFyehVQPf0bvl+DxH2zE3AjU9wABUJ6VK98XU0KkrsBfTx9XR zYVQ== 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:cc; bh=1P5MK419CiPsslmLTmG5fBWqfS0HB9ZOwXuACeSc74Y=; b=KBbifQBLn3fXVNmdTB12NZWi1zyybkJsPu9rPNNFUbbb/bwAfATPtv4vylyEpjTc/G eG/oO7yMadfe2zmkUeOJS9pYYdxLdssL0WfzTvMhKI5lmqKOjHALvStCqjJnMgDEPnD1 sQHeZWc4Bwew3ItBtMXMvzEOYF6E4dOD6RGgM49zZagwR6EKgxf1EKB2ju566khJCZ00 Pd4K60qnb4UphiHemUy6b2b/60MhycL9wMDnzuTq1LTfd88mtZcjyrohX8sB+qWdgtHb TObFbejWesns7vg+ThqksPdbHBmlq1bpE6XeEEty0H68hqrUxOqZF86RUbcrnbbqC3Ci 4wAA== X-Gm-Message-State: AIkVDXKJAYT1GxP235DX8CekG+wLniFrl+LSQqNiMUJ28A9GXQYe17foLSEAWQfmkKQHnOkAWHzcR55ielQEPQ== X-Received: by 10.55.192.137 with SMTP id v9mr3541245qkv.305.1485448583965; Thu, 26 Jan 2017 08:36:23 -0800 (PST) MIME-Version: 1.0 Received: by 10.12.173.40 with HTTP; Thu, 26 Jan 2017 08:36:23 -0800 (PST) In-Reply-To: References: <44k29l27f2.fsf@lowell-desk.lan> From: krad Date: Thu, 26 Jan 2017 16:36:23 +0000 Message-ID: Subject: Re: Building Kernel and World with -j To: Kevin Oberman Cc: FreeBSD-STABLE Mailing List , Walter Parker 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: Thu, 26 Jan 2017 16:36:25 -0000 I use these options in my src.conf WITH_FAST_DEPEND=yes WITH_CCACHE_BUILD=yes I can often get build times of about 9 min but can got upto about 30 mins in jenkins depending on how much has changed. This is on a i5-3570K. It does have 32GB and ssd l2arc. Those times are for a buildworld, buildkernel packages for pkgbase. and j is set to 5 On 23 January 2017 at 18:09, Kevin Oberman wrote: > On Mon, Jan 23, 2017 at 6:10 AM, Lowell Gilbert < > freebsd-stable-local@be-well.ilk.org> wrote: > > > Walter Parker writes: > > > > > 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? > > > > As a general rule, it's safe. But don't report failures from a > > parallel build. > > > > This is not so much an issue of parallel builds being unsupported > > as of the logs being harder to read. > > > Use of parallel builds of world and kernel are and have been supported > since at least 10.0. If a parallel build fails, the first step is usually > to do a single-job build. If it succeeds, there is a bug in the make > scripts that should be reported. If the single-job build also fails, a bug > should be reported with any errors included from the non-parallel build as > the parallel build makes the error context very difficult or even > impossible to determine from the log. > > Generally, I think the number of jobs should be slightly greater than the > number of available CPU threads. Back in 10.0 days I ran some tests that > showed the for 4 and 8 thread systems the improvements for large numbers of > jobs peaked at about CPU thread count + 2 and significantly larger numbers > of jobs caused a slight deterioration in performance. This was not true on > early hyper-threaded CPUs which did not effectively optimize > hyper-threading and things may have changed in the 6 or 7 years since I > tested and may be very different for systems with large numbers of threads > seen in servers today. > -- > Kevin Oberman, Part time kid herder and retired Network Engineer > E-mail: rkoberman@gmail.com > PGP Fingerprint: D03FB98AFA78E3B78C1694B318AB39EF1B055683 > _______________________________________________ > freebsd-stable@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" >