Time for drm-ci-next?

[Daniel Vetter]

On Fri, Jul 05, 2024 at 12:31:36PM -0700, Rob Clark wrote:
> On Fri, Jul 5, 2024 at 3:36 AM Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
> >
> > On Thu, Jul 04, 2024 at 08:40:26AM -0700, Rob Clark wrote:
> > > On Thu, Jul 4, 2024 at 7:08 AM Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
> > > >
> > > > On Tue, Jul 02, 2024 at 05:32:39AM -0700, Rob Clark wrote:
> > > > > On Fri, Jun 28, 2024 at 10:44 AM Daniel Vetter <daniel at ffwll.ch> wrote:
> > > > > >
> > > > > > On Thu, Jun 27, 2024 at 11:51:37AM -0700, Rob Clark wrote:
> > > > > > > On Wed, Jun 26, 2024 at 10:47 AM Daniel Vetter <daniel at ffwll.ch> wrote:
> > > > > > > >
> > > > > > > > On Wed, Jun 26, 2024 at 11:38:30AM +0300, Dmitry Baryshkov wrote:
> > > > > > > > > On Wed, Jun 26, 2024 at 09:32:44AM GMT, Daniel Vetter wrote:
> > > > > > > > > > On Mon, Jun 24, 2024 at 10:25:25AM -0300, Helen Koike wrote:
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > On 24/06/2024 02:34, Vignesh Raman wrote:
> > > > > > > > > > > > Hi,
> > > > > > > > > > > >
> > > > > > > > > > > > On 15/03/24 22:50, Rob Clark wrote:
> > > > > > > > > > > > > Basically, I often find myself needing to merge CI patches on top of
> > > > > > > > > > > > > msm-next in order to run CI, and then after a clean CI run, reset HEAD
> > > > > > > > > > > > > back before the merge and force-push.  Which isn't really how things
> > > > > > > > > > > > > should work.
> > > > > > > > > >
> > > > > > > > > > This sounds more like you want an integration tree like drm-tip. Get msm
> > > > > > > > > > branches integrated there, done. Backmerges just for integration testing
> > > > > > > > > > are not a good idea indeed.
> > > > > > >
> > > > > > > But AFAIU this doesn't help for pre-merge testing, ie. prior to a
> > > > > > > patch landing in msm-next
> > > > > > >
> > > > > > > My idea was to have a drm-ci-next managed similar to drm-misc-next, if
> > > > > > > we have needed drm/ci patches we could push them to drm-ci-next, and
> > > > > > > then merge that into the driver tree (along with a PR from drm-ci-next
> > > > > > > to Dave).
> > > > > >
> > > > > > I guess I'm confused about what kind of pre-merge testing we're talking
> > > > > > about then ... Or maybe this just doesn't work too well with the linux
> > > > > > kernel. The model is that you have some pile of trees, they're split up,
> > > > > > and testing of all the trees together is done in integration trees like
> > > > > > linux-next or drm-tip.
> > > > >
> > > > > pre-merge: for msm we've been collecting up patches from list into a
> > > > > fast-forward MR which triggers CI before merging to msm-next/msm-fixes
> > > > >
> > > > > Ideally drm-misc and other trees would do similar, we'd catch more
> > > > > regressions that way.  For example, in msm-next the nodebugfs build is
> > > > > currently broken, because we merged drm-misc-next at a time when
> > > > > komeda was broken:
> > > > >
> > > > > https://gitlab.freedesktop.org/drm/msm/-/jobs/60575681#L9520
> > > > >
> > > > > If drm-misc was using pre-merge CI this would have been caught and the
> > > > > offending patch dropped.
> > > >
> > > > That sounds more like we should push on the drm-misc pre-merge CI boulder
> > > > to move it uphill, than add even more trees to make it even harder to get
> > > > there long term ...
> > > >
> > > > Short term it helps locally to have finer trees, but only short term and
> > > > only very locally.
> > >
> > > The path to have fewer trees (ideally only one for all of drm) is to
> > > use gitlab MRs to land everything :-)
> > >
> > > drm-ci-next is only a stop-gap.. but one that we need.  The
> > > ${branchname}-external-fixes trick covers _most_ cases where we need
> > > unrelated patches (ie. to fix random ToT breakage outside of drm or in
> > > core drm), but it doesn't help when the needed changes are yml
> > > (because gitlab processes all the yml before merging the
> > > -external-fixes branch).  This is where we need drm-ci-next, otherwise
> > > we are having to create a separate MR which cherry-picks drm/ci
> > > patches for doing the CI.  This is a rather broken process.
> >
> > So what I don't get is ... if we CI drm-misc, how does that not help
> > improve the situation here? Step one would be post-merge (i.e. just enable
> > CI in the repo), then get MRs going.
> 
> I guess post-merge is better than nothing.. but pre-merge is better.
> 
> post-merge can work if you have a "sheriff" system where someone
> (perhaps on a rotation) is actively monitoring results and "revert and
> ask questions later" when something breaks.  Pre-merge ensures the
> interested party is involved in the process ;-)

So ... make that happen? And it doesn't have to be for all of drm-misc,
mesa after all switched over to MR also on a bit a driver/area basis. So
agreeing among all drm-ci folks to use gitlab MR in drm-misc for pre-merge
testing shouldn't be that hard to make happen. And unlike a separate
branch it's not some kind of detour with a good chance to get stuck in a
local optimum.
-Sima
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch