Re: Fwd: wip/new-model review

["Jasper St. Pierre" <jstpierre mecheye net>]

On Mon, Jul 22, 2013 at 6:00 PM, Colin Walters <walters verbum org> wrote:

On Sat, 2013-07-20 at 14:36 -0400, Jasper St. Pierre wrote:

>
> Uh, well, not really. The build process takes inputs: snapshot.json,
> last-build/, src/, and produces binaries which are put into repo/,
> along with log files, etc. I see "last-build/" as an optimization of
> not wasting CPU for things we've already compiled. It's not strictly
> necessary, it will just take a lot longer if it's missing.

"last-build" seems strange to me; why not instead have an explicit
caching layer?  Let's say that I want to build both x32 and x86_64
binaries.  With OpenEmbedded/Bitbake, if you do the x32 build, and then
later do a x86_64 build, if you have them share a SSTATE_CACHE, a lot of
the architecture independent work is just pulled from the cache.

I initially wanted to get rid of explicit lookasides, because I wanted to get rid of jsondb. I liked the idea of builds being entirely self-contained directories, without any need for setup. And I was sort of using symlinks for everything, so I figured I'd hammer a few more in here to hastily meet both goals. Having talked this over, I'm not so confident this is a great idea anymore.

 

With your "last-build" proposal I'd have to arbitrarily pick the x32
build as my "last-build", even though I'm building x86_64.

Well, like "repo", we can also link a cache layer in, but perhaps it's better to just have the explicit lookaside.

 

I was kind of going in the direction of having something sstate like
with the cache/ directory.

 

> It might seem a bit insensitive to say this, but I really don't care
> what the high-level UI is. We can figure out if we want a git-like one
> based off of the CWD, or one based on command line arguments, or
> config files, or envvars later.

Right...but the thing is it's going to be hard to merge this until
it's in a state where we have a functioning autobuilder *and* I can test
stuff locally.

Of course.

 

Will respond to the rest in a bit.

Looking forward to it.

--
  Jasper