[Openembedded-architecture] Heterogeneous System Proposal

Richard Purdie richard.purdie at linuxfoundation.org
Tue Dec 3 15:07:22 UTC 2019


On Tue, 2019-12-03 at 17:04 +1300, Paul Eggleton wrote:
> Taking just this part of the discussion for now (since it is a small
> familiar aspect to me)
> 
> On Tuesday, 3 December 2019 1:08:54 PM NZDT Mark Hatle wrote:
> > > You may want to consider this now. Adding system with the
> > > "nomachine"
> > > mode you mention is a nightmare scenario for parsing. Bitbake has
> > > a
> > > problem with knowing when to parse or not to parse since to
> > > 'skip'
> > > parsing a recipe, it needs to parse enough to know it should skip
> > > it.
> > > COMPATIBLE_MACHINE is implemented with the skip mechanism for
> > > example.
> > > If parsing is a concern (and I agree it is), you could probably
> > > get
> > > much further with a BBMASK approach to just the system-images
> > > recipe as
> > > then bitbake would know what it needs to parse without needing to
> > > read
> > > the recipes.
> > 
> > The problem I have with BBMASK is that when a user tries to do
> > something with
> > it, they don't get a reasonable error message.
> > 
> > For instance if I BBMASK out bash, and the user does bitbake bash
> > they get an
> > error.  Instead of a 'bash is unavailable because ...'.
> 
> The only practical way for that to work is the existing skip
> mechanism, since PN isn't always completely defined by the .bb
> filename, we need to actually parse to determine its value. gcc-cross 
> and other parts of the toolchain are examples. 
> 
> BBMASK is such a usability pain - both in your scenario but also in
> the reverse where you have to hack it until it only masks exactly
> what you do want masked - that I think we would be best advised not
> to make any more use of it than we currently do, especially if it's
> only to save a bit of time parsing.

If we don't like BBMASK (and I can see why), setting BBFILES to a
restricted path for that config could also work.

On a related note, should we improve the logging around BBMASK? There
is a lot of useless output in the debug messages we should remove but
that could be a good one to add...

Cheers,

Richard



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