From owner-freebsd-hackers@FreeBSD.ORG Mon Jun 11 22:51:51 2012 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id B2C2E1065672 for ; Mon, 11 Jun 2012 22:51:51 +0000 (UTC) (envelope-from yanegomi@gmail.com) Received: from mail-ob0-f182.google.com (mail-ob0-f182.google.com [209.85.214.182]) by mx1.freebsd.org (Postfix) with ESMTP id 7A6E48FC12 for ; Mon, 11 Jun 2012 22:51:51 +0000 (UTC) Received: by obcni5 with SMTP id ni5so9503131obc.13 for ; Mon, 11 Jun 2012 15:51:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=UDCbo/gb1nhGhNxew6ZhrmHI1uEnLtnS2LeyV6PErYc=; b=WwIS2AwLbgfHH3kAl1ZtTVXzEehnA2poLNsHPJYV7ip0bu3TciZvh+evNmVSAV0yst Gk90ZSx+jloKmnYhECyC06WikpZ3t6YWCUugR+eDxUz27CeBOjttBnMWULYEmGpF7zrO eJl2ScmHy/s/7WFwcYX+r3Ojawt21kHdF57pCt00fh4OX4YuNHFoIKuASBZ7csvKcxxS EaeA8IlAa+1yrI2aMYIyP9OTsLSx4tVb3q7Fw+DN0jE5t4g/md7HV/WC9wpwoQ0Vq7nC OPze8h2xC5cyLr/jtOlMnnY6FAPO7uPq3JIXpaX4Km/zKphgHDrGa4Pfmi9gd5IDKZ6q KdfA== MIME-Version: 1.0 Received: by 10.182.154.67 with SMTP id vm3mr18085215obb.57.1339455110888; Mon, 11 Jun 2012 15:51:50 -0700 (PDT) Received: by 10.76.98.77 with HTTP; Mon, 11 Jun 2012 15:51:50 -0700 (PDT) In-Reply-To: <4FD66F7E.2060404@brandonfa.lk> References: <4FD66F7E.2060404@brandonfa.lk> Date: Mon, 11 Jun 2012 15:51:50 -0700 Message-ID: From: Garrett Cooper To: Brandon Falk Content-Type: text/plain; charset=ISO-8859-1 Cc: freebsd-hackers@freebsd.org Subject: Re: FreeBSD Boot Times X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 11 Jun 2012 22:51:51 -0000 On Mon, Jun 11, 2012 at 3:21 PM, Brandon Falk wrote: > Greetings, > > I was just wondering what it is that FreeBSD does that makes it take so long > to boot. Booting into Ubuntu minimal or my own custom Linux distro, > literally takes 0.5-2 seconds to boot up to shell, where FreeBSD takes about > 10-20 seconds. I'm not sure if anything could be parallelized in the boot > process, but Linux somehow manages to do it. The Ubuntu install I do pretty > much consists of a shell and developers tools, but it still has a generic > kernel. There must be some sort of polling done in the FreeBSD boot process > that could be parallelized or eliminated. > > Anyone have any suggestions? > > Note: This isn't really an issue, moreso a curiosity. The single process nature of rc is a big part of the problem, as is the single AP bootup of FreeBSD right before multiuser mode. There are a number of threads that discuss this (look for parallel rc bootup or something like that in the current, hacker, and rc archives -- the most recent discussion was probably 6~9 months ago). Given past experience, a big part of getting past the parallelized rc mess would be to make services fail/wait gracefully for all their resources to come up before proceeding. It's not easy, but it's possible with enough resources. HTH, -Garrett