Draft: Add DependencyCheckSvc and optionally include it in AthenaHiveEventLoopMgr

Add DependencyCheckSvc and optionally include it in AthenaHiveEventLoopMgr. The purpose of it is to check both input and output dependencies so that we do not schedule anything that is not needed or require something that is not there. It is based on the default scheduler (but I wanted to avoid hacking Gaudi ).

A few questions:

• Is the current location fine?
• Is the way it is included fine?

Tagging @ssnyder, @akraszna, @fwinkl and @leggett for now.

cc @bwynne. Personally, I would think that feature could just be included in the scheduler. Or is there anything ATLAS-specific?

Not really. It just also adds output dependency check.

I've no problem with the idea in principle, but I do have some comments:

1. At the moment, the code seems to be close to what's in the Gaudi scheduler. Certainly the scheduler already finds unmet input dependencies in order to "load" them (i.e. assign to SGInputLoader). As @fwinkl suggests, this could mean including the new functionality in the scheduler would be better. Of course, if you just want the information soon then modifying Gaudi probably isn't the way to go...

2. It should be possible to do this entirely in the configuration layer now, I think. Not sure if that's useful, but it's something I looked at doing in the past.

3. I'm not sure what the purpose is. Do you simply want a report saying "these outputs aren't consumed by anything?" Maybe a Dot file showing the graph would be nice?

4. Presumably this is just for debugging and wouldn't run in production?

Cheers, Ben

We may want to run in production eventually, but for now it's for local development. I think longer term it would be nice to get it into Gaudi, but I wonder how long this would take to end up in master of Athena.

Does configuration also handle default keys?

Once the code is in Gaudi we can make it available in ATLAS within a few days. Either via a new release or cherry-picking the change.

I opened gaudi/Gaudi!1384 (merged), still need to test it using Atlas fork of Gaudi in Athena.

closed