From owner-freebsd-arch@freebsd.org Thu Dec 3 21:35:13 2015 Return-Path: Delivered-To: freebsd-arch@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 435B8A40D8E for ; Thu, 3 Dec 2015 21:35:13 +0000 (UTC) (envelope-from chmeeedalf@gmail.com) Received: from mail-oi0-x236.google.com (mail-oi0-x236.google.com [IPv6:2607:f8b0:4003:c06::236]) (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 EB68D14D6; Thu, 3 Dec 2015 21:35:12 +0000 (UTC) (envelope-from chmeeedalf@gmail.com) Received: by oige206 with SMTP id e206so57918097oig.2; Thu, 03 Dec 2015 13:35:12 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type:content-transfer-encoding; bh=nj8CNBTElQ28vL0hdPgrWzSJMhtF413RFTLGl5YyIxs=; b=G+cVPnn8xHbnkJsw6dBAmQj7C8HJM/eBBM9s21zGtyeyPpGVUgK9svloLQ9xM2+ys/ 3AYVAB9Vt3Hqi0R8ReW/9Xw+8kVhBS5eQ1S2qXSmUUReS9HuvVztl420GqCTBu8ygZIP XdxbLJpJgko7zeVirlW0arn0NgYJfqLNCWPW/C8yvcgKlwxSL7uwOMNplzmL4VpAYkfj VPwXCBSCN9OVronxcwkeScSUiqeCB3DS33Sszr/RtWGpuEBuiLzB+6yoVDXh9/H7vuUc JnERcwK1Au6bdiNIaaxR63E7wN8Xb8XjfhYuQKOrHDn8518opIt4ymFV3xxVz850ILec B2yQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alumni-cwru-edu.20150623.gappssmtp.com; s=20150623; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type:content-transfer-encoding; bh=nj8CNBTElQ28vL0hdPgrWzSJMhtF413RFTLGl5YyIxs=; b=YywU7wYhfP7N2E14HzJHJrE1X9JZTlAqYKwEFj9E1efDlhdTfAX3GTp265Ti647pyF vvsHxMJ0IUsnWHeEeVKr3dvKCanj6nEA581sJMvvb/T2PHfPHjKuhe/JpoK0O7E2+NTp kZ57QCu+ffJDyAVxuNmx09U/4wpCKrSjU4Nap8p7LblLhdveLe/UEJycl7zBXUKJ1cw+ e9H7U1XTS3XUXBMybz68veJ59/jYfKeO9p51EBO6GruQ+1wwRgV/wuXLddKeewpiKyDH qoTkIxsGV5L6fdQBjz+MvFPxJJgMUsdFTlpELFcEkxljKesVHn19HHSjEHmuggiaF/bF o4Hw== MIME-Version: 1.0 X-Received: by 10.202.201.67 with SMTP id z64mr9709071oif.24.1449178512222; Thu, 03 Dec 2015 13:35:12 -0800 (PST) Sender: chmeeedalf@gmail.com Received: by 10.182.210.195 with HTTP; Thu, 3 Dec 2015 13:35:12 -0800 (PST) In-Reply-To: <1449177325.6214.14.camel@freebsd.org> References: <1449177325.6214.14.camel@freebsd.org> Date: Thu, 3 Dec 2015 15:35:12 -0600 X-Google-Sender-Auth: 79E3E62BokBUMmA0Poxq2m0_LU8 Message-ID: Subject: Re: Removing build metadata, for reproducible kernel builds From: Justin Hibbits To: Ian Lepore Cc: Warner Losh , Ed Maste , "freebsd-arch@freebsd.org" Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 03 Dec 2015 21:35:13 -0000 On Thu, Dec 3, 2015 at 3:15 PM, Ian Lepore wrote: > On Thu, 2015-12-03 at 12:53 -0700, Warner Losh wrote: >> On Thu, Dec 3, 2015 at 12:55 AM, Ed Maste wrote: >> >> > On 3 December 2015 at 05:51, Warner Losh wrote: >> > > >> > > I noted in the review that I don=E2=80=99t like the default being no= . >> > > >> > > I also don=E2=80=99t like that we=E2=80=99re growing lots of differe= nt knobs that need >> > > to be set to get a repeatable build. Let=E2=80=99s have one, or barr= ing that, >> > > let=E2=80=99s have one that sets all the sub-knobs. >> > >> > My hope is that we'll have a reproducible build by default, and that >> > *no* knobs need to be set. That's what I intend with my patch. I can >> > rename the knob to WITH_/WITHOUT_REPRODUCIBLE_BUILD though if that's >> > generally desired. If there's a consensus to default to including the >> > metadata I'm fine with setting it in make release. >> >> >> I think this an unwise decision in the current form suggested. The kerne= l >> metadata has saved my butt enough times I really don't want to see it >> go by default. But see below for a reasonable (imho) middle ground that >> would be a good default. >> > > I'm curious why anyone wants this enabled by default, like... are we > missing something? Does it improve freebsd-update behavior maybe? > > If it's just for some general "reproducibility is good" philosophy then > I would counter with "information is even better, so don't throw it > away without a good reason." > > Reproducibility is good for some people, and completely useless for > others, and the people who need it aren't going to mind turning on a > knob or two to get what they want. > >> >> > > I think that host and path are more worthless than date and time >> > > in many environments. Who builds it likewise. Those are all things >> > > that are likely to change between builds, yet change the kernel >> > > image. I=E2=80=99d rather see it all gone when this option is in eff= ect. >> > >> > I don't follow -- other than the build iteration number (which I >> > indeed missed), it is all gone. >> > >> >> Yea I was reading things backwards. >> >> In the review, I suggested that if you've modified the tree (which the S= CM >> will tell you), then do the old format to preserve useful metadata that'= s >> really really needed and if not to use the shorter version. When you've >> modified the tree, reproducible builds aren't a concern at all. >> > > How are you going to determine what consitutes a modified tree? What > you think of as modifications may be what I call my baseline version. > > -- Ian svnversion resulting in a 'nnnnnnM'? - Justin