Minutes for LArSoft coordination meeting on October 9, 2018

Present	Vito Di Benedetto, Giuseppe Cerati, Lynn Garren, Robert Hatcher, Alex Himmel, Kyle Knoepfel, Saba Sehrish, Hans Wenzel
Remote	Erin Conley, Katherine Lato, Ben Morgan, Paul Russo, Gleb Sinev

Project status report [Giuseppe Cerati]

Q: if the plan is to also look at the code that can be factorized to be able to migrate?
A: For the first pass, we are only looking at the code as it is but making a note of potential candidates after they have been refactored.

The purpose is to upgarde LArSoft to use the new art release that also provides multi-threading
To enable multithreading you have to opt for it, the default art behavior is still sequential
[Kyle Knoepfel] and [Lynn Garren] have been working on this
Some key points and observations
art services are not the most well-defined constructs in art
Do not use callbacks directly in your code, for services
NuRandomService: upcoming change in the createEngine to return Art-owned reference to engine, so there is no need to interact with it directly
There should be no header guards in the files that are not intended to be included
art removed the ability to reconfigure modules several versions ago
ThreadSanitizer is a useful tool for data race detection, and was used by [Paul Russo] while working on multi-threading art.

Problem to address is that services must tbe configured in consistent ways across different art jobs.
a potential solution is to have a wrapper script (that looks at fhicl configurations, runs config_dumper as needed).
Conclusion: There was an agreement to have discussion(s) with the art and LArSoft experts to understand the requirements and possible solution proposal.

It is important to identify whether service is what is needed for a particular problem, and may be there are different options that can pursued for each of different use of service.