[bitbake-devel] [PATCH 00/26] runqueue changes

[Richard Purdie]

On Thu, 2019-07-11 at 01:05 +0100, Richard Purdie wrote:
> These changes set up the foundations so that we can work on two other
> significant problems:
> 
> a) reuse of sstate artefacts between multiconfig build tasks

I have spent a long time thinking about this so now the codebase was
ready it turned out not to be too hard to make it work. Patches aren't
tested apart from with the unittest but I've posted them and we can
take them from here.

> b) adapting the task queue 'on the fly' if the output of a task
> matches a previous output and hence we have sstate hash equivalency
> 
> Solving these would be great for OE!
> 
> I will follow up with more details on the future plans for the above
> and this code soon.

Adapting to new hashes "on the fly" is definitely going to be the
harder challenge.

This will involve the following steps:

a) Knowing there are new unitask hashes available and propagating that
information

b) Figuring out which tasks should now have their sstate retested

c) Test for sstate existence (if it doesn't exist, no point in going
further)

d) Ensure any normal tasks covered by the sstate task are not running,
wait if any are

e) Remove all those normal tasks from access by the normal task running
code

f) Enable those tasks in the scenequeue code

We have no existing code which moves things "backward" in the state
engine from normal task to scenequeue so this will be new ground, but
should be feasible.

I'm going to wait for the current patches to settle before I look into
this any further though.

Cheers,

Richard