Date: Thu, 03 Dec 2015 14:45:09 -0700 From: Ian Lepore <ian@freebsd.org> To: Justin Hibbits <jrh29@alumni.cwru.edu> Cc: Warner Losh <imp@bsdimp.com>, Ed Maste <emaste@freebsd.org>, "freebsd-arch@freebsd.org" <freebsd-arch@freebsd.org> Subject: Re: Removing build metadata, for reproducible kernel builds Message-ID: <1449179109.6214.19.camel@freebsd.org> In-Reply-To: <CAHSQbTBTefh6dfcn%2B0nUfjyMvtVuimzocPrnPDTkY1nXU7y9Ww@mail.gmail.com> References: <CAPyFy2AYeN9XNg=b0=JMWDC9ctWarfiZ-5zQorOPhguDJgxYpg@mail.gmail.com> <D9AF1C8B-431C-4359-988F-FDEEF8FAD981@bsdimp.com> <CAPyFy2CZYV%2B-5pDQjCA4Btct1VZUyEQUuL2iU1z07Ff-n2Y9Hg@mail.gmail.com> <CANCZdfqP3=%2BBHM_%2B=ZrNouGrXW5WAwHC87F2teEi%2BE2j-AMm6g@mail.gmail.com> <1449177325.6214.14.camel@freebsd.org> <CAHSQbTBTefh6dfcn%2B0nUfjyMvtVuimzocPrnPDTkY1nXU7y9Ww@mail.gmail.com>
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On Thu, 2015-12-03 at 15:35 -0600, Justin Hibbits wrote: > On Thu, Dec 3, 2015 at 3:15 PM, Ian Lepore <ian@freebsd.org> wrote: > > On Thu, 2015-12-03 at 12:53 -0700, Warner Losh wrote: > > > On Thu, Dec 3, 2015 at 12:55 AM, Ed Maste <emaste@freebsd.org> > > > wrote: > > > > > > > On 3 December 2015 at 05:51, Warner Losh <imp@bsdimp.com> > > > > wrote: > > > > > > > > > > I noted in the review that I don¢t like the default being no. > > > > > > > > > > I also don¢t like that we¢re growing lots of different knobs > > > > > that need > > > > > to be set to get a repeatable build. Let¢s have one, or > > > > > barring that, > > > > > let¢s 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 kernel > > > 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¢d rather see it all gone when this option is in > > > > > effect. > > > > > > > > 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 SCM > > > 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 > svnversion isn't going to be able to return anything useful inside one of my build sandboxes in which there is no hint of svn anything. -- Ian
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